IBM z/OS ACF2 STIG
IBM z/OS ACF2 Security Technical Implementation Guide. Version v8 r15, released April 24, 2024.
ACF2-SM-000020: IBM z/OS DFSMS Program Resources must be properly defined and protected.
Refer to the load modules residing in the following Load libraries to determine Program resource definitions: SYS1.DGTLLIB for DFSMSdfp/ISMF SYS1.DGTLLIB for DFSMSdss/ISMF SYS1.DFQLLIB for DFSMShsm If the installation moves these modules to another load library the installation-defined load library must be used in the program protection. If the ACF2 resources are defined with a default access of NONE, this is not a finding. If the ACF2 resource access authorizations restrict access to the appropriate personnel, this is not a finding. Refer to the chapter titled 'Protecting the Storage Management Subsystem' in the IBM z/OS DFSMSdfp Storage Administration Guide to assist with guidance on appropriate access.
Discussion
To mitigate the risk of unauthorized access to sensitive information by entities that have been issued certificates by DoD-approved PKIs, all DoD systems (e.g., web servers and web portals) must be properly configured to incorporate access control methods that do not rely solely on the possession of a certificate for access. Successful authentication must not automatically give an entity access to an asset or security boundary. Authorization procedures and controls must be implemented to ensure each authenticated entity also has a validated and current authorization. Authorization is the process of determining whether an entity, once authenticated, is permitted to access a specific asset. Information systems use access control policies and enforcement mechanisms to implement this requirement. Access control policies include: identity-based policies, role-based policies, and attribute-based policies. Access enforcement mechanisms include: access control lists, access control matrices, and cryptography. These policies and mechanisms must be employed by the application to control access between users (or processes acting on behalf of users) and objects (e.g., devices, files, records, processes, programs, and domains) in the information system.
Fix
Note: The resource type, resources, and/or resource prefixes identified below are examples of a possible installation. The actual resource type, resources, and/or resource prefixes are determined when the product is actually installed on a system through the product's installation guide and can be site specific. Refer to the chapter titled "Protecting the Storage Management Subsystem" in the IBM z/OS DFSMSdfp Storage Administration Guide. Use SMS Program Resources tables to determine the resources, access requirements for SMS Program Resources. Ensure the guidelines for the resource type, resources, and/or generic equivalent specified. The ACF2 resources as designated in the above table are defined with a default access of PREVENT. The ACF2 resource access authorizations restrict access to the appropriate personnel as designated in the above tables. The following commands are provided as a sample for implementing resource controls: $KEY(ACBFUTO2) TYPE(PGM) UID(********) ALLOW UID(*) PREVENT F ACF2,REBUILD(PGM)
Rating Info
DISA Cat II. NIST impact 3.
Expert Comment
None
ACF2-OS-002410: IBM z/OS system administrator must develop a procedure to terminate all sessions and network connections related to nonlocal maintenance when nonlocal maintenance is completed.
Ask the system administrator for the procedure to terminate all sessions and network connections related to nonlocal maintenance when nonlocal maintenance is completed. If there is no procedure, this is a finding.
Discussion
If a maintenance session or connection remains open after maintenance is completed, it may be hijacked by an attacker and used to compromise or damage the system. Some maintenance and test tools are either standalone devices with their own operating systems or are applications bundled with an operating system. Nonlocal maintenance and diagnostic activities are those activities conducted by individuals communicating through a network, either an external network (e.g., the Internet) or an internal network. Local maintenance and diagnostic activities are those activities carried out by individuals physically present at the information system or information system component and not communicating across a network connection.
Fix
Develop a procedure to terminate all sessions and network connections related to nonlocal maintenance when nonlocal maintenance is completed.
Rating Info
DISA Cat II. NIST impact 3.
Expert Comment
None
ACF2-OS-000350: IBM z/OS sensitive and critical system data sets must not exist on shared DASD.
Check HMC, VM, and z/OS on how to validate and determine a DASD volume(s) is shared. Note: In VM issue the command "QUEUE DASD SYSTEM" this display will show shared volume(s) and indicates the number of systems sharing the volume. Validate all machines that require access to these shared volume(s) have the volume(s) mounted. Obtain a map or list VTOC of the shared volume(s). Check if shared volume(s) contain any critical or sensitive data sets. Identify shared and critical or sensitive data sets on the system being audited. These data sets can be APF, LINKLIST, LPA, Catalogs, etc, as well as product data sets. If all of the critical or sensitive data sets identified on shared volume(s) are protected and justified to be on shared volume(s), this is not a finding. List critical or sensitive data sets are possible security breaches, if not justified and not protected on systems having access to the data set(s) and on shared volume(s).
Discussion
Preventing unauthorized information transfers mitigates the risk of information, including encrypted representations of information, produced by the actions of prior users/roles (or the actions of processes acting on behalf of prior users/roles) from being available to any current users/roles (or current processes) that obtain access to shared system resources (e.g., registers, main memory, hard disks) after those resources have been released back to information systems. The control of information in shared resources is also commonly referred to as object reuse and residual information protection. This requirement generally applies to the design of an information technology product, but it can also apply to the configuration of particular information system components that are, or use, such products. This can be verified by acceptance/validation processes in DoD or other government agencies. There may be shared resources with configurable protections (e.g., files in storage) that may be assessed on specific information system components.
Fix
Configure all identified volumes of shared DASD to bel valid within the following. HMC VM z/OS If the shared volume(s) are valid and systems having access to these shared volume(s) are valid, map disk/VTOC list to obtain data sets on the shared volume(s). From this list obtain a list of sensitive and critical system data sets that are found on the shared volume(s). Ensure that the data sets are justified to be shared on the system and to reside on the shared volume(s). The ISSO will review all access requirements to validate that sensitive and critical system data sets are protected from unauthorized access across all systems that have access to the shared volume(s), thereby protecting the data set(s) whether the data set(s) are used or not used on the systems that have the shared volume(s) available to them.
Rating Info
DISA Cat II. NIST impact 3.
Expert Comment
None
ACF2-FT-000060: IBM z/OS FTP.DATA configuration statements for the FTP Server must specify the BANNER statement.
Refer to the Data configuration file specified on the SYSFTPD DD statement in the FTP started task JCL. If the BANNER statement is coded, this is not a finding.
Discussion
The structure and content of error messages must be carefully considered by the organization and development team. The extent to which the information system is able to identify and handle error conditions is guided by organizational policy and operational requirements.
Fix
Configure the FTP.DATA CONFIGURATION STATEMENT to include the following: BANNER [An HFS file, e.g., /etc/ftp.banner]
Rating Info
DISA Cat II. NIST impact 3.
Expert Comment
None
ACF2-ES-000270: CA-ACF2 must limit Write or greater access to Libraries containing EXIT modules to system programmers only.
Examine the system for active exit modules. You may need system administrator help for this. Third-party software products can determine standard and dynamic exits loaded in the system. If all the exits are found within APF, LPA, and LINKLIST, this is not applicable. If ESM data set rules for libraries that contain system exit modules restrict UPDATE and ALLOCATE access to only z/OS systems programming personnel, this is not a finding. If the ESM data set rules for libraries that contain exit modules specify that all UPDATE and ALLOCATE access will be logged, this is not a finding.
Discussion
Access control policies include: identity-based policies, role-based policies, and attribute-based policies. Access enforcement mechanisms include: access control lists, access control matrices, and cryptography. These policies and mechanisms must be employed by the application to control access between users (or processes acting on behalf of users) and objects (e.g., devices, files, records, processes, programs, and domains) in the information system. This requirement applies to operating systems with software libraries that are accessible and configurable, as in the case of interpreted languages. Software libraries also include privileged programs which execute with escalated privileges. Only qualified and authorized individuals must be allowed to obtain access to information system components for purposes of initiating changes, including upgrades and modifications. Privileged functions include, for example, establishing accounts, performing system integrity checks, or administering cryptographic key management activities. Non-privileged users are individuals that do not possess appropriate authorizations. Circumventing intrusion detection and prevention mechanisms or malicious code protection mechanisms are examples of privileged functions that require protection from non-privileged users. Satisfies: SRG-OS-000080-GPOS-00048, SRG-OS-000259-GPOS-00100, SRG-OS-000324-GPOS-00125
Fix
Using the ESM, protect the data sets associated with all product exits installed in the z/OS environment. This reduces the potential of a hacker adding a routine to a library and possibly creating an exposure. See that all exits are tracked using a CMP. Develop usermods to include the source/object code used to support the exits. Have systems programming personnel review all z/OS and other product exits to confirm that the exits are required and are correctly installed. Configure ESM data set rules for all update and alter access to libraries containing z/OS and other system level exits will be logged using the ACP's facilities. Only systems programming personnel will be authorized to update the libraries containing z/OS and other system level exits.
Rating Info
DISA Cat I. NIST impact 4.
Expert Comment
None
ACF2-OS-000170: IBM z/OS PARMLIB CLOCKxx must have the Accuracy PARM coded properly.
Refer to the CLOCKxx member of PARMLIB. If the ACCURACY parm is not coded, this is a finding. If the ACCURACY parm is coded to "1000", this is not a finding.
Discussion
Inaccurate time stamps make it more difficult to correlate events and can lead to an inaccurate analysis. Determining the correct time, a particular event occurred on a system is critical when conducting forensic analysis and investigating system events. Sources outside the configured acceptable allowance (drift) may be inaccurate. Synchronizing internal information system clocks provides uniformity of time stamps for information systems with multiple system clocks and systems connected over a network. Organizations should consider endpoints that may not have regular access to the authoritative time server (e.g., mobile, teleworking, and tactical endpoints).
Fix
Define the CLOCKxx statement to include the ACCURACY parm set to "1000".
Rating Info
DISA Cat II. NIST impact 3.
Expert Comment
None
ACF2-OS-000080: IBM z/OS Required SMF data record types must be collected.
Refer to IEASYS00 member in SYS1.PARMLIB Concatenation. Determine proper SMFPRMxx member. If all of the required SMF record types identified below are collected, this is not a finding. IBM SMF Records to be collected at a minimum: 0 (00) - IPL 6 (06) - External Writer/ JES Output Writer/ Print Services Facility (PSF) 7 (07) - [SMF] Data Lost 14 (0E) - INPUT or RDBACK Data Set Activity 15 (0F) - OUTPUT, UPDAT, INOUT, or OUTIN Data Set Activity 17 (11) - Scratch Data Set Status 18 (12) - Rename Non-VSAM Data Set Status 24 (18) - JES2 Spool Offload 25 (19) - JES3 Device Allocation 26 (1A) - JES Job Purge 30 (1E) - Common Address Space Work 32 (20) - TSO/E User Work Accounting 41 (29) - DIV Objects and VLF Statistics 42 (2A) - DFSMS statistics and configuration 43 (2B) - JES Start 45 (2D) - JES Withdrawal/Stop 47 (2F) - JES SIGNON/Start Line (BSC)/LOGON 48 (30) - JES SIGNOFF/Stop Line (BSC)/LOGOFF 49 (31) - JES Integrity 52 (34) - JES2 LOGON/Start Line (SNA) 53 (35) - JES2 LOGOFF/Stop Line (SNA) 54 (36) - JES2 Integrity (SNA) 55 (37) - JES2 Network SIGNON 56 (38) - JES2 Network Integrity 57 (39) - JES2 Network SYSOUT Transmission 58 (3A) - JES2 Network SIGNOFF 60 (3C) - VSAM Volume Data Set Updated 61 (3D) - Integrated Catalog Facility Define Activity 62 (3E) - VSAM Component or Cluster Opened 64 (40) - VSAM Component or Cluster Status 65 (41) - Integrated Catalog Facility Delete Activity 66 (42) - Integrated Catalog Facility Alter Activity 80 (50) - RACF/TOP SECRET Processing 81 (51) - RACF Initialization 82 (52) - ICSF Statistics 83 (53) - RACF Audit Record For Data Sets 90 (5A) - System Status 92 (5C) except subtypes 10, 11 - OpenMVS File System Activity 102 (66) - DATABASE 2 Performance 103 (67) - IBM HTTP Server 110 (6E) - CICS/ESA Statistics 118 (76) - TCP/IP Statistics 119 (77) - TCP/IP Statistics 199 (C7) - TSOMON 230 (E6) - ACF2 or as specified in ACFFDR (vendor-supplied default is 230) 231 (E7) - TSS logs security events under this record type
Discussion
Without establishing when events occurred, it is impossible to establish, correlate, and investigate the events leading up to an outage or attack. In order to compile an accurate risk assessment and provide forensic analysis, it is essential for security personnel to know when events occurred (date and time). Associating event types with detected events in the operating system audit logs provides a means of investigating an attack; recognizing resource utilization or capacity thresholds; or identifying an improperly configured operating system. SMF data collection is the basic unit of tracking of all system functions and actions. Included in this tracking data are the audit records from each of the ACPs and system. If the required SMF data record types are not being collected, then accountability cannot be monitored, and its use in the execution of a contingency plan could be compromised. Satisfies: SRG-OS-000004-GPOS-00004, SRG-OS-000038-GPOS-00016, SRG-OS-000039-GPOS-00017, SRG-OS-000040-GPOS-00018, SRG-OS-000041-GPOS-00019, SRG-OS-000042-GPOS-00021, SRG-OS-000064-GPOS-00033, SRG-OS-000239-GPOS-00089, SRG-OS-000240-GPOS-00090, SRG-OS-000241-GPOS-00091, SRG-OS-000255-GPOS-00096, SRG-OS-000303-GPOS-00120, SRG-OS-000327-GPOS-00127, SRG-OS-000365-GPOS-00152, SRG-OS-000392-GPOS-00172, SRG-OS-000458-GPOS-00203, SRG-OS-000461-GPOS-00205, SRG-OS-000462-GPOS-00206, SRG-OS-000463-GPOS-00207, SRG-OS-000465-GPOS-00209, SRG-OS-000466-GPOS-00210, SRG-OS-000467-GPOS-00211, SRG-OS-000468-GPOS-00212, SRG-OS-000470-GPOS-00214, SRG-OS-000471-GPOS-00215, SRG-OS-000471-GPOS-00216, SRG-OS-000472-GPOS-00217, SRG-OS-000473-GPOS-00218, SRG-OS-000474-GPOS-00219, SRG-OS-000475-GPOS-00220, SRG-OS-000476-GPOS-00221, SRG-OS-000477-GPOS-00222
Fix
Ensure that SMF recording options are consistent with those outlined below. IBM SMF Records to be collected at a minimum: 0 (00) - IPL 6 (06) - External Writer/ JES Output Writer/ Print Services Facility (PSF) 7 (07) - [SMF] Data Lost 14 (0E) - INPUT or RDBACK Data Set Activity 15 (0F) - OUTPUT, UPDAT, INOUT, or OUTIN Data Set Activity 17 (11) - Scratch Data Set Status 18 (12) - Rename Non-VSAM Data Set Status 24 (18) - JES2 Spool Offload 25 (19) - JES3 Device Allocation 26 (1A) - JES Job Purge 30 (1E) - Common Address Space Work 32 (20) - TSO/E User Work Accounting 41 (29) - DIV Objects and VLF Statistics 42 (2A) - DFSMS statistics and configuration 43 (2B) - JES Start 45 (2D) - JES Withdrawal/Stop 47 (2F) - JES SIGNON/Start Line (BSC)/LOGON 48 (30) - JES SIGNOFF/Stop Line (BSC)/LOGOFF 49 (31) - JES Integrity 52 (34) - JES2 LOGON/Start Line (SNA) 53 (35) - JES2 LOGOFF/Stop Line (SNA) 54 (36) - JES2 Integrity (SNA) 55 (37) - JES2 Network SIGNON 56 (38) - JES2 Network Integrity 57 (39) - JES2 Network SYSOUT Transmission 58 (3A) - JES2 Network SIGNOFF 60 (3C) - VSAM Volume Data Set Updated 61 (3D) - Integrated Catalog Facility Define Activity 62 (3E) - VSAM Component or Cluster Opened 64 (40) - VSAM Component or Cluster Status 65 (41) - Integrated Catalog Facility Delete Activity 66 (42) - Integrated Catalog Facility Alter Activity 80 (50) - RACF/TOP SECRET Processing 81 (51) - RACF Initialization 82 (52) - ICSF Statistics 83 (53) - RACF Audit Record For Data Sets 90 (5A) - System Status 92 (5C) except subtypes 10, 11 - OpenMVS File System Activity 102 (66) - DATABASE 2 Performance 103 (67) - IBM HTTP Server 110 (6E) - CICS/ESA Statistics 118 (76) - TCP/IP Statistics 119 (77) - TCP/IP Statistics 199 (C7) - TSOMON 230 (E6) - ACF2 or as specified in ACFFDR (vendor-supplied default is 230) 231 (E7) - TSS logs security events under this record type
Rating Info
DISA Cat II. NIST impact 3.
Expert Comment
None
ACF2-OS-002390: IBM z/OS system administrator must develop a procedure to notify system administrators and ISSOs of account enabling actions.
Ask the system administrator for the procedure to notify system administrators and ISSOs of account enabling actions. If no procedures are in place, this is a finding.
Discussion
Once an attacker establishes access to a system, the attacker often attempts to create a persistent method of reestablishing access. One way to accomplish this is for the attacker to enable an existing disabled account. Sending notification of account enabling actions to the system administrator and ISSO is one method for mitigating this risk. Such a capability greatly reduces the risk that operating system accessibility will be negatively affected for extended periods of time and also provides logging that can be used for forensic purposes.
Fix
Develop and document a procedure to notify system administrators and ISSOs of account enabling actions.
Rating Info
DISA Cat II. NIST impact 3.
Expert Comment
None
ACF2-ES-000710: ACF2 MAINT GSO record value if specified must be restricted to production storage management user.
From the ACF Command screen enter: SET CONTROL(GSO) LIST LIKE(MAINT-) If the GSO MAINT record values conform to the following requirements, this is not a finding. Specifies the logonid, program, and library combinations used for system maintenance functions. NOTE: For logonids that match environments described in records, no SMF logging records will be created. NOTE: Entries will be restricted to production storage management user accounts and programs. If there is any deviation from the above requirements in the GSO MAINT record values, this is a finding.
Discussion
Control of program execution is a mechanism used to prevent execution of unauthorized programs. Some operating systems may provide a capability that runs counter to the mission or provides users with functionality that exceeds mission requirements. This includes functions and services installed at the operating system level. Some of the programs, installed by default, may be harmful or may not be necessary to support essential organizational operations (e.g., key missions, functions). Removal of executable programs is not always possible; therefore, establishing a method of preventing program execution is critical to maintaining a secure system baseline. Methods for complying with this requirement include restricting execution of programs in certain environments, while preventing execution in other environments; or limiting execution of certain program functionality based on organization-defined criteria (e.g., privileges, subnets, sandboxed environments, or roles).
Fix
Configure the MAINT GSO value to be specified as restricted to production storage management user accounts and programs. Specifies the logonid, program, and library combinations used for system maintenance functions. NOTE: For logonids that match environments described in records, no SMF logging records will be created. NOTE: Entries will be restricted to production storage management user accounts and programs.
Rating Info
DISA Cat II. NIST impact 3.
Expert Comment
None
ACF2-OS-000160: IBM z/OS SNTP daemon (SNTPD) must be active.
Verify the operating system, for networked systems, compares internal information system clocks at least every 24 hours with a server which is synchronized to one of the redundant United States Naval Observatory (USNO) time servers, or a time server designated for the appropriate DoD network (NIPRNet/SIPRNet), and/or the Global Positioning System (GPS). If it does not, this is a finding.
Discussion
Inaccurate time stamps make it more difficult to correlate events and can lead to an inaccurate analysis. Determining the correct time, a particular event occurred on a system is critical when conducting forensic analysis and investigating system events. Sources outside the configured acceptable allowance (drift) may be inaccurate. Synchronizing internal information system clocks provides uniformity of time stamps for information systems with multiple system clocks and systems connected over a network. Organizations should consider endpoints that may not have regular access to the authoritative time server (e.g., mobile, teleworking, and tactical endpoints).
Fix
Obtain a copy of this sample procedure from SEZAINST and store it in one of your PROCLIB concatenation data sets. Perform the following step to start SNTPD as a procedure: Invoke the procedure using the system operator start command. The following sample, SEZAINST(SNTPD), shows how to start SNTPD as a procedure: //* //* Sample procedure for the Simple Network Time Protocol (SNTP) //* //* z/OS Communications Server Version 1 Release 13 //* SMP/E Distribution Name: SEZAINST(EZASNPRO) //* //* Copyright: Licensed Materials - Property of IBM //* 5650-ZOS //* Copyright IBM Corp. 2002, 2015 //* //* Status: CSV2R2 //* //SNTPD EXEC PGM=SNTPD,REGION=4096K,TIME=NOLIMIT, //PARM='/ -d' //SYSPRINT DD SYSOUT=*,DCB=(RECFM=F,LRECL=132,BLKSIZE=132) //SYSIN DD DUMMY //SYSERR DD SYSOUT=* //SYSOUT DD SYSOUT=*,DCB=(RECFM=F,LRECL=132,BLKSIZE=132) //CEEDUMP DD SYSOUT=* //SYSABEND DD SYSOUT=*
Rating Info
DISA Cat II. NIST impact 3.
Expert Comment
None
ACF2-ES-000800: CA-ACF2 userids found inactive for more than 35 days must be suspended.
From the ISPF Command Shell enter: ACF If every user shows an ACC-DATE=mm/dd/yy within the past 35 days, this is not a finding. NOTE: VALID FOR INTERACTIVE USERIDS, NOT VALID FOR STARTED TASK USERIDS AND BATCH USERIDS.
Discussion
Inactive identifiers pose a risk to systems and applications because attackers may exploit an inactive identifier and potentially obtain undetected access to the system. Owners of inactive accounts will not notice if unauthorized access to their user account has been obtained. Operating systems need to track periods of inactivity and disable application identifiers after 35 days of inactivity.
Fix
Develop a procedure to check all userids for inactivity more than 35 days. If found, the information system security officer (ISSO) must suspend an account, but not delete it until it is verified by the local ISSO that the user no longer requires access. If verification is not received within 60 days, the account may be deleted.
Rating Info
DISA Cat II. NIST impact 3.
Expert Comment
None
ACF2-ES-000700: ACF2 APPLDEF GSO record if used must have supporting documentation indicating the reason it was used.
From the ACF Command screen enter: SET CONTROL(GSO) LIST LIKE(APPLDEF-) If the GSO APPLDEF record does not exist, this is not a finding. If the GSO APPLDEF record does exist and no supporting documentation is available, this is a finding.
Discussion
Failure to restrict network connectivity only to authorized systems permits inbound connections from malicious systems. It also permits outbound connections that may facilitate exfiltration of DoD data.
Fix
For any APPLDEF GSO record used, it must have supporting documentation indicating the reason it was used. The APPLDEF record is optional.
Rating Info
DISA Cat III. NIST impact 2.
Expert Comment
None
ACF2-TC-000100: IBM z/OS TCP/IP AT-TLS policy must be properly configured in Policy Agent.
Use the z/OS UNIX pasearch -t command to query information from the z/OS UNIX Policy Agent. The command is issued from the UNIX System Services shell. Examine the results for AT-TLS initiation and control statements. If there are no AT-TLS initiation and controls statements, this is a finding. Verify the statements specify a FIPS 140-2 compliant value. If none of the following values are present, this is a finding. ECDHE_ECDSA_AES_128_CBC_SHA256 ECDHE_ECDSA_AES_256_CBC_SHA384 ECDHE_RSA_AES_128_CBC_SHA256 ECDHE_RSA_AES_256_CBC_SHA384 TLS_RSA_WITH_3DES_EDE_CBC_SHA TLS_RSA_WITH_AES_128_CBC_SHA TLS_RSA_WITH_AES_128_CBC_SHA256 TLS_RSA_WITH_AES_256_CBC_SHA TLS_RSA_WITH_AES_256_CBC_SHA256
Discussion
If events associated with nonlocal administrative access or diagnostic sessions are not logged, a major tool for assessing and investigating attacks would not be available. This requirement addresses auditing-related issues associated with maintenance tools used specifically for diagnostic and repair actions on organizational information systems. Nonlocal maintenance and diagnostic activities are conducted by individuals communicating through an external network (e.g., the internet) or an internal network. Local maintenance and diagnostic activities are carried out by individuals physically present at the information system or information system component and not communicating across a network connection. This requirement applies to hardware/software diagnostic test equipment or tools. This requirement does not cover hardware/software components that may support information system maintenance, yet are a part of the system; for example, the software implementing "ping," "ls," "ipconfig," or the hardware and software implementing the monitoring port of an Ethernet switch.
Fix
Develop a plan of action to implement the required changes. Ensure the following items are in effect for TCP/IP resources. Develop AT-TLS policy. Install in the policy agent. Ensure the statements specify a FIPS 140-2 compliant value of the following: ECDHE_ECDSA_AES_256_CBC_SHA384 ECDHE_RSA_AES_128_CBC_SHA256 ECDHE_RSA_AES_256_CBC_SHA384 TLS_RSA_WITH_3DES_EDE_CBC_SHA TLS_RSA_WITH_AES_128_CBC_SHA TLS_RSA_WITH_AES_128_CBC_SHA256 TLS_RSA_WITH_AES_256_CBC_SHA TLS_RSA_WITH_AES_256_CBC_SHA256
Rating Info
DISA Cat II. NIST impact 3.
Expert Comment
None
ACF2-SL-000030: IBM z/OS Syslog daemon must be properly defined and secured.
The syslog daemon is defined as SYSLOGD. From the ACF command screen enter: SET LID LIST SYSLOGD If the Syslog daemon is not defined, this is a finding. If the SYSLOGD logonid is not defined with the STC attribute, this is a finding. If the SYSLOGD userid has UID(0), HOME('/'), and PROGRAM('/bin/sh') specified in the OMVS segment, this is not a finding. If Syslog daemon is started from /etc/rc then ensure that the _BPX_JOBNAME and _BPX_USERID environment variables are assigned a value of SYSLOGD.
Discussion
The Syslog daemon, known as syslogd, is a zOS UNIX daemon that provides a central processing point for log messages issued by other zOS UNIX processes. It is also possible to receive log messages from other network-connected hosts. Some of the IBM Communications Server components that may send messages to syslog are the FTP, TFTP, zOS UNIX Telnet, DNS, and DHCP servers. The messages may be of varying importance levels including general process information, diagnostic information, critical error notification, and audit-class information. Primarily because of the potential to use this information in an audit process, there is a security interest in protecting the syslogd process and its associated data. The Syslog daemon requires special privileges and access to sensitive resources to provide its system services. Failure to properly define and control the Syslog daemon could lead to unauthorized access. This exposure may result in the compromise of the integrity and availability of the operating system environment, ACP, and customer data.
Fix
Define the Syslog daemon logonid as SYSLOGD with the STC attribute. To set up and use as an MVS Started Proc, the following sample commands are provided: SET LID INSERT SYSLOGD NAME(SYSLOGD STC) GROUP(stctcpx) STC The SYSLOGD userid has UID(0), HOME('/'), and PROGRAM('/bin/sh') specified in the OMVS segment. SET PROFILE(USER) DIVISION(OMVS) INSERT SYSLOGD UID(0) HOME(/) PROGRAM(/bin/sh) F ACF2,REBUILD(USR),CLASS(P) If /etc/rc is used to start the Syslog daemon ensure that the _BPX_JOBNAME and _BPX_ USERID environment variables are assigned a value of SYSLOGD.
Rating Info
DISA Cat II. NIST impact 3.
Expert Comment
None
ACF2-ES-000530: IBM z/OS must have the RULEVLD and RSRCVLD attributes specified for LOGONIDs with the SECURITY attribute.
From the ACF Command screen enter: SET LID LIST IF(SECURITY) If all logonids with the SECURITY attribute also have the RULEVLD and RSRCVLD attributes specified, this not a finding. If any logonid with the SECURITY attribute does not have the RULEVLD and/or RSRCVLD attributes specified, this is a finding.
Discussion
The use of security policy filters provides protection for the confidentiality of data by restricting the flow of data. A crucial part of any flow control solution is the ability to configure policy filters. This allows the operating system to enforce multiple and different security policies. Policy filters serve to enact and enforce the organizational policy as it pertains to controlling data flow.
Fix
Configure Logonids with the SECURITY attribute to have the RULEVLD and RSRCVLD attributes specified. If a logonid is granted the SECURITY privilege, it is mandatory that RULEVLD and RSRCVLD attributes will also be specified for the logonid. Example: SET LID CHANGE logonid RULEVLD RSRCVLD
Rating Info
DISA Cat II. NIST impact 3.
Expert Comment
None
ACF2-ES-000870: ACF2 PSWD GSO record value must be set to require the change of at least 50 percent of the total number of characters when passwords are changed.
From an ACF command screen enter: SET CONTROL(GSO) LIST PSWD If "PSWDSIM" is set to "4", this is not a finding.
Discussion
If the operating system allows the user to consecutively reuse extensive portions of passwords, this increases the chances of password compromise by increasing the window of opportunity for attempts at guessing and brute-force attacks. The number of changed characters refers to the number of changes required with respect to the total number of positions in the current password. In other words, characters may be the same within the two passwords; however, the positions of the like characters must be different. If the password length is an odd number then number of changed characters must be rounded up. For example, a password length of 15 characters must require the change of at least eight characters.
Fix
Configure the Password option "PSWDSIM" to "4".
Rating Info
DISA Cat II. NIST impact 3.
Expert Comment
None
ACF2-OS-002240: IBM z/OS must employ a session manager to manage retaining a users session lock until that user reestablishes access using established identification and authentication procedures.
Ask the system administrator for the configuration parameters for the session manager in use. If there is no session manager in use, this is a finding. If the session manager is not configured to retain a user's session lock until that user reestablishes access using established identification and authentication procedures, this is a finding.
Discussion
A session lock is a temporary action taken when a user stops work and moves away from the immediate physical vicinity of the information system but does not want to log out because of the temporary nature of the absence. The session lock is implemented at the point where session activity can be determined. Regardless of where the session lock is determined and implemented, once invoked, the session lock must remain in place until the user reauthenticates. No other activity aside from reauthentication must unlock the system.
Fix
Configure the session manager to retain a user's session lock until that user reestablishes access using established identification and authentication procedures.
Rating Info
DISA Cat II. NIST impact 3.
Expert Comment
None
ACF2-SH-000050: IBM z/OS SSH daemon must be configured to use a FIPS 140-2 compliant cryptographic algorithm.
Locate the SSH daemon configuration file, which may be found in "/etc/ssh/" directory. Alternately: From UNIX System Services ISPF Shell navigate to ribbon select tools. Select option 1 - Work with Processes. If SSH Daemon is not active, this is not a finding. Examine SSH daemon configuration file. sshd_config If there are no ciphers lines or the ciphers list contains any cipher not starting with "3des" or "aes", this is a finding. If the MACs line is not configured to "hmac-sha1" or greater, this is a finding. Examine the z/OS-specific sshd server system-wide configuration. zos_sshd_config If any of the following is untrue, this is a finding. FIPSMODE=YES CiphersSource=ICSF MACsSource=ICSF
Discussion
Without confidentiality protection mechanisms, unauthorized individuals may gain access to sensitive information via a remote access session. Remote access is access to DoD nonpublic information systems by an authorized user (or an information system) communicating through an external, non-organization-controlled network. Remote access methods include, for example, dial-up, broadband, and wireless. Encryption provides a means to secure the remote connection to prevent unauthorized access to the data traversing the remote access connection (e.g., RDP), thereby providing a degree of confidentiality. The encryption strength of a mechanism is selected based on the security categorization of the information. Satisfies: SRG-OS-000033-GPOS-00014, SRG-OS-000120-GPOS-00061
Fix
Edit the SSH daemon configuration and remove any ciphers not starting with "3des" or "aes". If necessary, add a "Ciphers" line using FIPS 140-2 compliant algorithms. Configure for message authentication to MACs "hmac-sha1" or greater. Edit the z/OS-specific sshd server system-wide configuration file configuration as follows: FIPSMODE=YES CiphersSource=ICSF MACsSource=ICSF
Rating Info
DISA Cat I. NIST impact 4.
Expert Comment
None
ACF2-ES-000100: CA-ACF2 must properly define users that have access to the CONSOLE resource in the TSOAUTH resource class.
NOTE: If CLASMAP defines TSOAUTH or OPERCMDS as anything other than the default of TYPE(TSO) or TYPE(OPR), replace TSO or OPR below with the appropriate three letters. If the CONSOLE resource is not defined to the TSOAUTH resource class, this is not a finding. At the discretion of the ISSO, users may be allowed to issue z/OS system commands from a TSO session. With this in mind, configure the following for users granted the CONSOLE resource in the TSOAUTH resource class or users assigned the CONSOLE attribute: Logonids are restricted to the INFO level on the AUTH field specified in the OPERPARM segment of the user profile record. Logonids are restricted to READ access to the MVS.MCSOPER.userid resource defined in the OPERCMDS resource class (i.e., resource rules for TYPE(OPR)). If all of the above are true, this is not a finding. If any of the above are untrue, this is a finding.
Discussion
To mitigate the risk of unauthorized access to sensitive information by entities that have been issued certificates by DoD-approved PKIs, all DoD systems (e.g., web servers and web portals) must be properly configured to incorporate access control methods that do not rely solely on the possession of a certificate for access. Successful authentication must not automatically give an entity access to an asset or security boundary. Authorization procedures and controls must be implemented to ensure each authenticated entity also has a validated and current authorization. Authorization is the process of determining whether an entity, once authenticated, is permitted to access a specific asset. Information systems use access control policies and enforcement mechanisms to implement this requirement. Access control policies include: identity-based policies, role-based policies, and attribute-based policies. Access enforcement mechanisms include: access control lists, access control matrices, and cryptography. These policies and mechanisms must be employed by the application to control access between users (or processes acting on behalf of users) and objects (e.g., devices, files, records, processes, programs, and domains) in the information system.
Fix
Configuration should ensure that all users that have access to the CONSOLE resource in the TSOAUTH resource class are properly defined. Ensure the CONSOLE resource is not defined to the TSOAUTH resource class. Example: $KEY(CONSOLE) TYPE(TSO) - UID(*) PREVENT At the discretion of the ISSO, users may be allowed to issue z/OS system commands from a TSO session. With this in mind, ensure the following items are in effect for users granted the CONSOLE resource in the TSOAUTH resource class or users assigned the CONSOLE attribute: Logonids are restricted to the INFO level on the AUTH field specified in the OPERPARM segment of the user profile record. Logonids are restricted to READ access to the MVS.MCSOPER.userid resource defined in the OPERCMDS resource class (i.e., resource rules for TYPE(OPR)). Example: $KEY(MVS) TYPE(OPR) MCSOPER.logonid UID(sysprgmr) SERVICE(READ) ALLOW COMPILE ' ACF2.MVA.OPR(MVS)' STORE F ACF2,REBUILD(OPR)
Rating Info
DISA Cat II. NIST impact 3.
Expert Comment
None
ACF2-ES-000570: CA-ACF2 RULEOPTS GSO record values must be set to the values specified.
From the ACF Command enter: SET CONTROL(GSO) LIST RULEOPTS If the following options are defined, this is not a finding. NO$NOSORT CENTRAL CHANGE DECOMP(AUDIT SECURITY) | DECOMP(AUDIT) | DECOMP(SECURITY) The other RULEOPTS values should be assigned carefully as they affect the Rules and Infostorage databases.
Discussion
Configuring the operating system to implement organization-wide security implementation guides and security checklists ensures compliance with federal standards and establishes a common security baseline across DoD that reflects the most restrictive security posture consistent with operational requirements.
Fix
Configure the GSO RULEOPTS record values to conform to the following requirements. NO$NOSORT CENTRAL CHANGE DECOMP(AUDIT SECURITY) | DECOMP(AUDIT) | DECOMP(SECURITY) The other RULEOPTS values should be assigned carefully as they affect the Rules and Infostorage databases. Example: SET C(GSO) INSERT RULEOPTS NO$NOSORT CENTRAL CHANGE NOCOMPDYN DECOMP(AUDIT SECURITY) F ACF2,REFRESH(RULEOPTS)
Rating Info
DISA Cat II. NIST impact 3.
Expert Comment
None
ACF2-US-000230: IBM z/OS Attributes of UNIX user accounts used for account modeling must be defined in accordance with security requirements.
If this is a Classified system, this is Not Applicable. From an ACF2 command line enter: SET CONTROL(GSO) SHOW UNIXOPTS Alternately: Refer to the following report produced by the ACF2 Data Collection: - ACF2CMDS.RPT(ACFGSO) - ACF2CMDS.RPT(OMVSUSER) Note: This check applies to any user identifier (LOGONID) used to model OMVS access on the mainframe. This includes any DFTUSER; MODLUSER and BPX.UNIQUE.USER. If MODLUSER is specified then UNIQUSER must be specified. If DFTUSER or MODLUSER is not defined in the UNIXOPTS record, this is not a finding. If ALL user identifiers (LOGONID) defined to DFTUSER or MODLUSER. or BPX.UNIQUE.USER user account is defined as follows, this is not a finding: A non-writable HOME directory: Shell program specified as "/bin/echo" or "/bin/false" Note: The shell program must have one of the specified values. The HOME directory must have a value (i.e., not be allowed to default).
Discussion
To assure accountability and prevent unauthenticated access, organizational users must be identified and authenticated to prevent potential misuse and compromise of the system. Organizational users include organizational employees or individuals the organization deems to have equivalent status of employees (e.g., contractors). Organizational users (and processes acting on behalf of users) must be uniquely identified and authenticated to all accesses, except for the following: 1) Accesses explicitly identified and documented by the organization. Organizations document specific user actions that can be performed on the information system without identification or authentication; and 2) Accesses that occur through authorized use of group authenticators without individual authentication. Organizations may require unique identification of individuals in group accounts (e.g., shared privilege accounts) or for detailed accountability of individual activity.
Fix
Define DFTUSER or MODLUSER or BPX.UNIQUE.USER user account to be defined as follows: A non-writable HOME directory: Shell program specified as "/bin/echo" or "/bin/false" Note: The shell program must have one of the specified values. The HOME directory must have a value (i.e., not be allowed to default). Example: SET PROFILE(USER) DIV(OMVS) LIST OMVS INSERT OMVS HOME(/) OMVSPGM(/bin/false) UID(0)
Rating Info
DISA Cat II. NIST impact 3.
Expert Comment
None
ACF2-UT-000010: IBM z/OS startup user account for the z/OS UNIX Telnet Server must be defined properly.
From the ISPF Command Shell enter: OMVS CD /etc ls (to make sure OTELNET is active) cat otelnetd.conf If the otelnetd command specifies OMVS or OMVSKERN as the user, this is not a finding. If the otelnetd command specifies any user other than OMVS or OMVSKERN, this is a finding.
Discussion
To mitigate the risk of unauthorized access to sensitive information by entities that have been issued certificates by DoD-approved PKIs, all DoD systems (e.g., web servers and web portals) must be properly configured to incorporate access control methods that do not rely solely on the possession of a certificate for access. Successful authentication must not automatically give an entity access to an asset or security boundary. Authorization procedures and controls must be implemented to ensure each authenticated entity also has a validated and current authorization. Authorization is the process of determining whether an entity, once authenticated, is permitted to access a specific asset. Information systems use access control policies and enforcement mechanisms to implement this requirement. Access control policies include: identity-based policies, role-based policies, and attribute-based policies. Access enforcement mechanisms include: access control lists, access control matrices, and cryptography. These policies and mechanisms must be employed by the application to control access between users (or processes acting on behalf of users) and objects (e.g., devices, files, records, processes, programs, and domains) in the information system.
Fix
Configure the otelnetd startup command in the inetd.conf file to be defined for the z/OS UNIX kernel.
Rating Info
DISA Cat II. NIST impact 3.
Expert Comment
None
ACF2-SH-000030: IBM z/OS SSH daemon must be configured with the Department of Defense (DoD) logon banner.
Locate the SSH daemon configuration file which may be found in /etc/ssh/ directory. Alternately: From UNIX System Services ISPF Shell navigate to ribbon select tools. Select option 1 - Work with Processes. If SSH Daemon is not active, this is not s finding. Examine SSH daemon configuration file. If Banner statement is missing or configured to none this is a finding. Ensure that the contents of the file specified on the banner statement contain a logon banner. The banner below is mandatory and deviations are not permitted except as authorized in writing by the DoD Chief Information Officer. If there is any deviation this is a finding. STANDARD MANDATORY DOD NOTICE AND CONSENT BANNER You are accessing a U.S. Government (USG) Information System (IS) that is provided for USG-authorized use only. By using this IS (which includes any device attached to this IS), you consent to the following conditions: -The USG routinely intercepts and monitors communications on this IS for purposes including, but not limited to, penetration testing, COMSEC monitoring, network operations and defense, personnel misconduct (PM), law enforcement (LE), and counterintelligence (CI) investigations. -At any time, the USG may inspect and seize data stored on this IS. -Communications using, or data stored on, this IS are not private, are subject to routine monitoring, interception, and search, and may be disclosed or used for any USG authorized purpose. -This IS includes security measures (e.g., authentication and access controls) to protect USG interests--not for your personal benefit or privacy. -Notwithstanding the above, using this IS does not constitute consent to PM, LE or CI investigative searching or monitoring of the content of privileged communications, or work product, related to personal representation or services by attorneys, psychotherapists, or clergy, and their assistants. Such communications and work product are private and confidential. See User Agreement for details.
Discussion
Display of a standardized and approved use notification before granting access to the publicly accessible operating system ensures privacy and security notification verbiage used is consistent with applicable federal laws, Executive Orders, directives, policies, regulations, standards, and guidance. System use notifications are required only for access via logon interfaces with human users and are not required when such human interfaces do not exist. The banner must be formatted in accordance with applicable DoD policy. Use the following verbiage for operating systems that can accommodate banners of 1300 characters: "You are accessing a U.S. Government (USG) Information System (IS) that is provided for USG-authorized use only. By using this IS (which includes any device attached to this IS), you consent to the following conditions: -The USG routinely intercepts and monitors communications on this IS for purposes including, but not limited to, penetration testing, COMSEC monitoring, network operations and defense, personnel misconduct (PM), law enforcement (LE), and counterintelligence (CI) investigations. -At any time, the USG may inspect and seize data stored on this IS. -Communications using, or data stored on, this IS are not private, are subject to routine monitoring, interception, and search, and may be disclosed or used for any USG-authorized purpose. -This IS includes security measures (e.g., authentication and access controls) to protect USG interests--not for your personal benefit or privacy. -Notwithstanding the above, using this IS does not constitute consent to PM, LE or CI investigative searching or monitoring of the content of privileged communications, or work product, related to personal representation or services by attorneys, psychotherapists, or clergy, and their assistants. Such communications and work product are private and confidential. See User Agreement for details." Use the following verbiage for operating systems that have severe limitations on the number of characters that can be displayed in the banner: "I've read & consent to terms in IS user agreem't." Satisfies: SRG-OS-000228-GPOS-00088, SRG-OS-000023-GPOS-00006
Fix
Configure the banner statement to a file that contains the Department of Defense (DoD) logon banner. Ensure that the contents of the file specified on the banner statement contain a logon banner. The banner below is mandatory and deviations are not permitted except as authorized in writing by the DoD Chief Information Officer. STANDARD MANDATORY DOD NOTICE AND CONSENT BANNER You are accessing a U.S. Government (USG) Information System (IS) that is provided for USG-authorized use only. By using this IS (which includes any device attached to this IS), you consent to the following conditions: -The USG routinely intercepts and monitors communications on this IS for purposes including, but not limited to, penetration testing, COMSEC monitoring, network operations and defense, personnel misconduct (PM), law enforcement (LE), and counterintelligence (CI) investigations. -At any time, the USG may inspect and seize data stored on this IS. -Communications using, or data stored on, this IS are not private, are subject to routine monitoring, interception, and search, and may be disclosed or used for any USG authorized purpose. -This IS includes security measures (e.g., authentication and access controls) to protect USG interests--not for your personal benefit or privacy. -Notwithstanding the above, using this IS does not constitute consent to PM, LE or CI investigative searching or monitoring of the content of privileged communications, or work product, related to personal representation or services by attorneys, psychotherapists, or clergy, and their assistants. Such communications and work product are private and confidential. See User Agreement for details."
Rating Info
DISA Cat II. NIST impact 3.
Expert Comment
None
ACF2-FT-000070: IBM z/OS FTP Control cards must be properly stored in a secure PDS file.
Provide a list(s) of the locations for all FTP Control cards within a given application/AIS, ensuring no FTP control cards are within in-stream JCL, JCL libraries or any open access data sets. The list must indicate which application uses the PDS, and access requirements for those PDSes (who and what level of access). Lists/spreadsheet used for documenting the meeting of this requirement must be maintained by the responsible Application/AIS Team, available upon request and not maintained by Mainframe ISSO. Obtain the list/spreadsheet from the Application/AIS Team. Access to FTP scripts and/or data files located on host system(s) that contain FTP userid and or password will be restricted to those individuals responsible for the application connectivity and who have a legitimate requirement to know the userid and password on a remote system. FTP Control Cards within In-stream JCL, within JCL libraries or open access libraries/data sets is a finding. If there is anyone not listed within the spreadsheet by userid that has access of Read or greater to the FTP control cards, this is a finding.
Discussion
Configuring the operating system to implement organization-wide security implementation guides and security checklists ensures compliance with federal standards and establishes a common security baseline across DoD that reflects the most restrictive security posture consistent with operational requirements.
Fix
Create a list or spreadsheet of the locations where FTP control cards are stored, who should have access to those libraries, and which applications the FTP control cards are for. Add Columns for all people permitted access to the secured PDS. Make sure that the FTP control Cards for each FTP are stored in a secure PDS and that they are not placed in the JCL libraries or in the in-stream JCL for each FTP.
Rating Info
DISA Cat II. NIST impact 3.
Expert Comment
None
ACF2-ES-000610: CA-ACF2 database must be backed up on a scheduled basis.
From the ACF Command enter: SET CONTROL(GSO) SHOW SYSTEMS If based on the information provided, it can be determined that the ESM database is being backed up on a regularly scheduled basis, this is not a finding. If it cannot be determined that the ESM database is being backed up on a regularly scheduled basis, this is a finding.
Discussion
Configuring the operating system to implement organization-wide security implementation guides and security checklists ensures compliance with federal standards and establishes a common security baseline across DoD that reflects the most restrictive security posture consistent with operational requirements.
Fix
Configure ACF2 GSO option to ensure that procedures are in place to back up all ACP files needed for recovery on a scheduled basis. At a minimum, this means nightly backup of the ACP databases and of other critical security files (such as the ACP parameter file). More frequent backups (two or three times daily) will reduce the time necessary to effect recovery. The ISSO will verify that the backup job(s) run successfully.
Rating Info
DISA Cat II. NIST impact 3.
Expert Comment
None
ACF2-OS-000220: IBM z/OS Emergency LOGONIDs must be properly defined.
Ask the system administrator to provide a list of all emergency logonids available to the site along with the associated function of each. If there are no emergency logonids defined, ask the system administrator for an alternate documented procedure to handle emergencies. If there are no emergency logonids and no documented emergency procedure, this is a finding. If emergency logonids exist, at a minimum, a logonid will exist with the security administration attributes specified in accordance with the following requirements: For emergency IDs with security administration privileges, but which cannot access and update system data sets: ACCOUNT JCL JOB MONITOR NONON CNCL RULEVLD RSRCVLD SECURITY TSO TSOPROC(xxxxxxxx) TSOACCT(none) An additional class of logonids can exist to perform all operating system functions except ESM administration. These emergency logonid/logonid(s) will have ability to access and update all system data sets, but will not have security administration privileges. See the following requirements: JCL JOB MONITOR NON CNCL (Will force logging of all activity.) TSO TSOPROC(xxxxxxxx) TSOACCT(none) All emergency logonid/logonid(s) are to be implemented with logging to provide an audit trail of their activities. All emergency logonid/logonid(s) are to be maintained in both the ESM and SYS1.UADS to ensure they are available in the event that the ESM is not functional. All emergency logonid/logonid(s) will have distinct, different passwords in SYS1.UADS and in the ESM, and the site is to establish procedures to ensure that the passwords differ. The password for any ID in SYS1.UADS is never to match the password for the same ID in the ESM. All emergency logonid/logonid(s) will have documented procedures to provide a mechanism for the use of the IDs. Their release for use is to be logged, and the log is to be maintained by the ISSO. When an emergency logonid is released for use, its password is to be reset by the ISSO within 12 hours. If all the emergency logonid items above are true, this is not a finding. If any item above is untrue, this is a finding.
Discussion
Activity under unusual conditions can indicate hostile activity. For example, what is normal activity during business hours can indicate hostile activity if it occurs during off hours. Depending on mission needs and conditions, account usage restrictions based on conditions and circumstances may be critical to limit access to resources and data to comply with operational or mission access control requirements. Thus, the operating system must be configured to enforce the specific conditions or circumstances under which organization-defined accounts can be used (e.g., by restricting usage to certain days of the week, time of day, or specific durations of time).
Fix
Ensure that Emergency Logonids use these fields to enforce restrictions for Emergency logonids. Two classes of emergency logonids may exist. The following privileges and specifications will be used for these logonids: Note: Only the emergency logonid with the security administration logonid attributes is required. (1) For emergency IDs with the ability to access and update all system data sets, but which do not have security administration privileges: NOFSRETAIN JCL JOB MONITOR NON CNCL (Will force logging of all activity.) TSO TSOPROC(xxxxxxxx) TSOACCT(none) Example: SET LID INSERT logonid NOFSRETAIN JCL JOB MONITOR NON-CNCL TSO TSOPRC(xxxxxxxx) TSOACCT(none) (2) For emergency IDs with security administration privileges, but which cannot access and update system data sets: ACCOUNT NOFSRETAIN JCL JOB MONITOR NONON CNCL RULEVLD RSRCVLD SECURITY TSO TSOPROC(xxxxxxxx) TSOACCT(none) Example: SET LID INSERT logonid ACCOUNT NOFSRETAIN JCL JOB MONITOR RULEVLD RSRCVLD NONON-CNCL SECURITY TSO TSOPRC(xxxxxxxx) TSOACCT(none) If no emergency logonids are in use on the system, develop and document a procedure to manage emergencies access to the system.
Rating Info
DISA Cat II. NIST impact 3.
Expert Comment
None
ACF2-ES-000950: ACF2 SECVOLS GSO record value must be set to VOLMASK(). Any local changes are justified and documented with the ISSO.
From an ACF command screen enter: SET CONTROL(GSO) LIST SECVOLS If the GSO SECVOLS record values conform to the following requirements, this is not a finding. VOLMASK() NOTE: Local changes will be documented in writing with supporting documentation. If there is any deviation from the above requirements in the GSO SECVOLS record values, this is a finding.
Discussion
The SECVOLS record defines the DASD and tape volumes for which CA-ACF2 provides volume-level protection. Information at rest refers to the state of information when it is located on a secondary storage device (e.g., disk drive and tape drive, when used for backups) within an operating system. This requirement addresses protection of user-generated data, as well as operating system-specific configuration data. Organizations may choose to employ different mechanisms to achieve confidentiality and integrity protections, as appropriate, in accordance with the security category and/or classification of the information.
Fix
Define the GSO SECVOLS record values to conform to the following requirements. VOLMASK() Example: SET C(GSO) INSERT SECVOLS VOLMASK() F ACF2,REFRESH(SECVOLS)
Rating Info
DISA Cat II. NIST impact 3.
Expert Comment
None
ACF2-ES-000510: IBM z/OS TSO GSO record values must be set to the values specified.
From the ACF Command screen enter: SET CONTROL(GSO) LIST TSO If the GSO TSO record values conform to the following requirements, this is not a finding. ACCOUNT(1) BYPASS(#) CHAR(BS) CMDLIST() NOIKJEFLD1 LINE(ATTN) LOGONCK PERFORM(0) PROC(site defined) NOQLOGON REGION(site defined) SUBCLSS() SUBHOLD() SUBMSG() TIME(0) TSOSOUT(A) UNIT(SYSDA) WAITIME(1-60)
Discussion
Configuring the operating system to implement organization-wide security implementation guides and security checklists ensures compliance with federal standards and establishes a common security baseline across DoD that reflects the most restrictive security posture consistent with operational requirements.
Fix
Configure the GSO TSO record values to conform to the following requirements. ACCOUNT(1) BYPASS(#) CHAR(BS) CMDLIST() NOIKJEFLD1 LINE(ATTN) LOGONCK PERFORM(0) PROC(site defined) NOQLOGON REGION(site defined) SUBCLSS() SUBHOLD() SUBMSGC() TIME(0) TSOSOUT(A) UNIT(SYSDA) WAITIME(1-60) Example: SET C(GSO) INSERT TSO ACCOUNT(1) BYPASS(#) CHAR(BS) CMDLIST() NOIKJEFLD1 LINE(ATTN) LOGONCK PERFORM(0) PROC(IKJACCNT) NOQLOGON REGION(4,096) SUBCLSS() SUBHOLD() SUBMSGC() TIME(0) TSOGNAME() TSOSOUT(A) UNIT(SYSDA) WAITIME(60) F ACF2,REFRESH(TSO)
Rating Info
DISA Cat II. NIST impact 3.
Expert Comment
None
ACF2-TN-000030: IBM z/OS SSL encryption options for the TN3270 Telnet Server must be specified properly for each statement that defines a SECUREPORT or within the TELNETGLOBALS.
Refer to the Profile configuration file specified on the PROFILE DD statement in the TCPIP started task JCL. If the following items are in effect for the configuration specified in the TCP/IP Profile configuration file, this is not a finding. NOTE: If an INCLUDE statement is coded in the TCP/IP Profile configuration file, the data set specified on this statement must be checked for the following items as well. NOTE: FIPS 140-2 minimum encryption is the accepted level of encryption and will override this requirement if greater. The TELNETGLOBALS block that specifies an ENCRYPTION statement states one or more of the below cipher specifications. Each TELNETPARMS block that specifies the SECUREPORT statement, specifies an ENCRYPTION statement that states one or more of the below cipher specifications, and the TELNETGLOBALS block does or does not specify an ENCRYPTION statement. Cipher Specifications SSL_3DES_SHA SSL_AES_256_SHA SSL_AES_128_SHA
Discussion
Without confidentiality protection mechanisms, unauthorized individuals may gain access to sensitive information via a remote access session. Remote access is access to DoD nonpublic information systems by an authorized user (or an information system) communicating through an external, non-organization-controlled network. Remote access methods include, for example, dial-up, broadband, and wireless. Encryption provides a means to secure the remote connection to prevent unauthorized access to the data traversing the remote access connection (e.g., RDP), thereby providing a degree of confidentiality. The encryption strength of a mechanism is selected based on the security categorization of the information. Satisfies: SRG-OS-000033-GPOS-00014, SRG-OS-000120-GPOS-00061, SRG-OS-000250-GPOS-00093, SRG-OS-000393-GPOS-00173, SRG-OS-000394-GPOS-00174, SRG-OS-000396-GPOS-00176, SRG-OS-000423-GPOS-00187, SRG-OS-000424-GPOS-00188, SRG-OS-000425-GPOS-00189, SRG-OS-000426-GPOS-00190, SRG-OS-000478-GPOS-00223
Fix
Configure the SECUREPORT and TELNETPARMS ENCRYPTION statements and/or the TELNETGLOBALS statement in the PROFILE.TCPIP file to conform to the requirements specified below. The TELNETGLOBALS block may specify an ENCRYPTION statement that specifies one or more of the below cipher specifications. Each TELNETPARMS block that specifies the SECUREPORT statement, an ENCRYPTION statement is coded with one or more of the below cipher specifications, and the TELNETGLOBALS block does or does not specify an ENCRYPTION statement. To prevent the use of non FIPS 140-2 encryption, the TELNETGLOBALS block and/or each TELNETPARMS block that specifies an ENCRYPTION statement will specify one or more of the following cipher specifications: Cipher Specifications SSL_3DES_SHA SSL_AES_256_SHA SSL_AES_128_SHA Note: Always check for the minimum allowed in FIPS 140-2.
Rating Info
DISA Cat II. NIST impact 3.
Expert Comment
None
ACF2-JS-000010: IBM z/OS JESTRACE and/or SYSLOG resources must be protected in accordance with security requirements.
From the ACF command screen enter: Set RESOURCE(SPL) List like(localnodeid-) If the following resources in the JESSPOOL resource class (i.e., TYPE(SPL)) are configured as noted below, this is not a finding. localnodeid.JES2.$TRCLOG.taskid.-.JESTRACE localnodeid.+MASTER+.SYSLOG.jobid.-.SYSLOG or localnodeid.+BYPASS+.SYSLOG.jobid.-.SYSLOG NOTE: These resource rules may be more generic as long as they pertain directly to the JESTRACE and SYSLOG data sets. For example: localnodeid.JES2.-.-.-.JESTRACE localnodeid.+MASTER+.-.-.-.SYSLOG or localnodeid.+BYPASS+.-.-.-.SYSLOG NOTE: To determine the localnodeid by searching for OWNNODE in the NJEDEF statement, and then searching for NODE(nnnn) (where nnnn is the value specified by OWNNODE). The NAME parameter value specified on this NODE statement is the localnodeid. Another method is to issue the JES2 command $D NODE,NAME,OWNNODE=YES to obtain the NAME of the OWNNODE. If access authorization for the resources mentioned above is restricted to the following, this is not a finding. Logonid(s) associated with external writer(s) can have complete access. NOTE: An external writer is an STC that removes data sets from the JES spool. In this case, it is responsible for archiving the JESTRACE and SYSLOG data sets. The STC default name is XWTR and the external writer program is called IASXWR00. Systems personnel and security administrators responsible for diagnosing JES2 and z/OS problems can have complete access. Application Development and Application Support personnel responsible for diagnosing application problems can have READ access to the SYSLOG resource.
Discussion
To mitigate the risk of unauthorized access to sensitive information by entities that have been issued certificates by DoD-approved PKIs, all DoD systems (e.g., web servers and web portals) must be properly configured to incorporate access control methods that do not rely solely on the possession of a certificate for access. Successful authentication must not automatically give an entity access to an asset or security boundary. Authorization procedures and controls must be implemented to ensure each authenticated entity also has a validated and current authorization. Authorization is the process of determining whether an entity, once authenticated, is permitted to access a specific asset. Information systems use access control policies and enforcement mechanisms to implement this requirement. Access control policies include: identity-based policies, role-based policies, and attribute-based policies. Access enforcement mechanisms include: access control lists, access control matrices, and cryptography. These policies and mechanisms must be employed by the application to control access between users (or processes acting on behalf of users) and objects (e.g., devices, files, records, processes, programs, and domains) in the information system.
Fix
NOTE: If CLASMAP defines JESSPOOL as anything other than TYPE(SPL), replace SPL below with the appropriate three letters. Configure the following resources in the JESSPOOL resource class (i.e., TYPE(SPL)): localnodeid.JES2.$TRCLOG.taskid.-.JESTRACE localnodeid.+MASTER+.SYSLOG.jobid.-.SYSLOG or localnodeid.+BYPASS+.SYSLOG.jobid.-.SYSLOG NOTE: These resource rules may be more generic as long as they pertain directly to the JESTRACE and SYSLOG data sets. For example: localnodeid.JES2.-.-.-.JESTRACE localnodeid.+MASTER+.-.-.-.- or localnodeid.+BYPASS+.-.-.-.- NOTE: To determine the localnodeid by searching for OWNNODE in the NJEDEF statement, and then searching for NODE(nnnn) (where nnnn is the value specified by OWNNODE). The NAME parameter value specified on this NODE statement is the localnodeid. Another method is to issue the JES2 command $D NODE,NAME,OWNNODE=YES to obtain the NAME of the OWNNODE. Configure access authorization for the resources mentioned above is restricted to the following: Logonid(s) associated with external writer(s) can have complete access. NOTE: An external writer is a STC that removes data sets from the JES spool. In this case, it is responsible for archiving the JESTRACE and SYSLOG data sets. The STC default name is XWTR and the external writer program is called IASXWR00. Systems personnel and security administrators responsible for diagnosing JES2 and z/OS problems can have complete access. Application Development and Application Support personnel responsible for diagnosing application problems can have READ access to the SYSLOG resource. Example: SET R(SPL) $KEY(localnodeid) TYPE(SPL) -.SYSLOG.-.-.- UID(sysprgmr) ALLOW -.SYSLOG.-.-.- UID(seca) ALLOW -.SYSLOG.-.-.- UID(appdudt) SERVICE(READ) ALLOW -.SYSLOG.-.-.- UID(apps) SERVICE(READ) ALLOW -.$TRCLOG.-.-.- UID(sysprgmr) ALLOW -.$TRCLOG.-.-.- UID(seca) ALLOW - UID(*) PREVENT
Rating Info
DISA Cat II. NIST impact 3.
Expert Comment
None
ACF2-TC-000020: IBM z//OS must be configured to restrict all TCP/IP ports to ports, protocols, and/or services as defined in the PPSM CAL and vulnerability assessments.
Refer the TCPIP PROFILE DD statement to determine the TCP/IP Ports. If the PROFILE DD statement is not supplied, use the default search order to find thee PROFILE data set. See the IP Configuration Guide for a description of the search order for PROFILE.TCPIP. If the all the Ports included into the configuration are restricted to the ports, protocols, and/or services, as defined in the Ports, Protocols, and Services Management (PPSM) Category Assurance List (CAL) and vulnerability assessments, this is not a finding.
Discussion
Remote access services, such as those providing remote access to network devices and information systems, which lack automated control capabilities, increase risk and make remote user access management difficult at best. Remote access is access to DoD nonpublic information systems by an authorized user (or an information system) communicating through an external, non-organization-controlled network. Remote access methods include, for example, dial-up, broadband, and wireless. Operating system functionality (e.g., RDP) must be capable of taking enforcement action if the audit reveals unauthorized activity. Automated control of remote access sessions allows organizations to ensure ongoing compliance with remote access policies by enforcing connection rules of remote access applications on a variety of information system components (e.g., servers, workstations, notebook computers, smartphones, and tablets).
Fix
Configure TCP/IP PROFILE port definitions to adhere to ports, protocols, and/or services, as defined in the Ports, Protocols, and Services Management (PPSM) Category Assurance List (CAL) and vulnerability assessments.
Rating Info
DISA Cat II. NIST impact 3.
Expert Comment
None
ACF2-OS-002470: ACF2 system administrator must develop a procedure to disable account identifiers (individuals, groups, roles, and devices) after 35 days of inactivity.
Ask the system administrator for the procedure to disable account identifiers (individuals, groups, roles, and devices) after 35 days of inactivity. If there is no procedure this is a finding.
Discussion
Inactive identifiers pose a risk to systems and applications because attackers may exploit an inactive identifier and potentially obtain undetected access to the system. Owners of inactive accounts will not notice if unauthorized access to their user account has been obtained. Operating systems need to track periods of inactivity and disable application identifiers after 35 days of inactivity.
Fix
Develop a procedure to disable account identifiers (individuals, groups, roles, and devices) after 35 days of inactivity.
Rating Info
DISA Cat II. NIST impact 3.
Expert Comment
None
ACF2-CE-000030: All IBM z/OS digital certificates in use must have a valid path to a trusted Certification authority.
Execute the CA-ACF2 SAFCRRPT using the following as SYSIN input: RECORDID(-) DETAIL FIELDS(ISSUER SUBJECT ACTIVE EXPIRE TRUST) If no certificate information is found, this is not a finding. NOTE: Certificates are only valid when their Status is TRUST. Therefore, you may ignore certificates with the NOTRUST status during the following check. If the digital certificate information indicates that the issuer's distinguished name leads to one of the following, this is not a finding: a) A DoD PKI Root Certification Authority b) An External Root Certification Authority (ECA) c) An approved External Partner PKI's Root Certification Authority The DoD Cyber Exchange website contains information as to which certificates may be acceptable (https://public.cyber.mil/pki-pke/interoperability/ or https://cyber.mil/pki-pke/interoperability/). Examples of an acceptable DoD CA are: DoD PKI Class 3 Root CA DoD PKI Med Root CA
Discussion
Without path validation, an informed trust decision by the relying party cannot be made when presented with any certificate not already explicitly trusted. A trust anchor is an authoritative entity represented via a public key and associated data. It is used in the context of public key infrastructures, X.509 digital certificates, and DNSSEC. When there is a chain of trust, usually the top entity to be trusted becomes the trust anchor; it can be, for example, a Certification Authority (CA). A certification path starts with the subject certificate and proceeds through a number of intermediate certificates up to a trusted root certificate, typically issued by a trusted CA. This requirement verifies that a certification path to an accepted trust anchor is used for certificate validation and that the path includes status information. Path validation is necessary for a relying party to make an informed trust decision when presented with any certificate not already explicitly trusted. Status information for certification paths includes certificate revocation lists or online certificate status protocol responses. Validation of the certificate status information is out of scope for this requirement. Satisfies: SRG-OS-000066-GPOS-00034, SRG-OS-000403-GPOS-00182
Fix
Remove or replace certificates where the issuer's distinguished name does not lead to a DoD PKI Root Certification Authority, External Root Certification Authority (ECA), or an approved External Partner PKI's Root Certification Authority.
Rating Info
DISA Cat II. NIST impact 3.
Expert Comment
None
ACF2-VT-000020: IBM z/OS VTAM USSTAB definitions must not be used for unsecured terminals.
Ask the system administrator to supply the following information: - Documentation regarding terminal naming standards. - Documentation of all procedures controlling terminal logons to the system. - A complete list of all USS commands used by terminal users to log on to the system. - Members and data set names containing USSTAB and LOGAPPL definitions of all terminals that can log on to the system (e.g., SYS1.VTAMLST). - Members and data set names containing logon mode parameters. If USSTAB definitions are only used for secure terminals (e.g., terminals that are locally attached to the host or connected to the host via secure leased lines), this is not a finding. If USSTAB definitions are used for any unsecured terminals (e.g., dial up terminals or terminals attached to the Internet such as TN3270 or KNET 3270 emulation), this is a finding.
Discussion
If the operating system were to allow any user to make changes to software libraries, then those changes might be implemented without undergoing the appropriate testing and approvals that are part of a robust change management process. This requirement applies to operating systems with software libraries that are accessible and configurable, as in the case of interpreted languages. Software libraries also include privileged programs which execute with escalated privileges. Only qualified and authorized individuals must be allowed to obtain access to information system components for purposes of initiating changes, including upgrades and modifications.
Fix
Configure USSTAB definitions to be only used for secure terminals. Only terminals that are locally attached to the host or connected to the host via secure leased lines located in a secured area. Only authorized personnel may enter the area where secure terminals are located. USSTAB or LOGAPPL definitions are used to control logon from secure terminals. These terminals can log on directly to any VTAM application (e.g., TSO, CICS, etc.) of their choice and bypass Session Manager services. Secure terminals are usually locally attached to the host or connected to the host via a private LAN without access to an external network. Only authorized personnel may enter the area where secure terminals are located.
Rating Info
DISA Cat II. NIST impact 3.
Expert Comment
None
ACF2-ES-000330: CA-ACF2 Access to SYS1.LINKLIB must be properly protected.
Execute a data set list of access to SYS1.LINKLIB. If the ACF2 data set rules for SYS1.LINKLIB allow inappropriate (e.g., global READ) access, this is a finding. If data set rules for SYS1.LINKLIB do not restrict READ, WRITE, and ALLOCATE access to only systems programming personnel, this is a finding. If data set rules for SYS1.LINKLIB do not restrict READ and WRITE access to only domain-level security administrators, this is a finding. If data set rules for SYS1.LINKLIB do not restrict READ access to only system-level Started Tasks, authorized Data Center personnel, and auditors, this is a finding. If data set rules for SYS1.LINKLIB do not specify that all (i.e., failures and successes) WRITE and/or ALLOCATE access will be logged, this is a finding.
Discussion
If the operating system were to allow any user to make changes to software libraries, then those changes might be implemented without undergoing the appropriate testing and approvals that are part of a robust change management process. This requirement applies to operating systems with software libraries that are accessible and configurable, as in the case of interpreted languages. Software libraries also include privileged programs which execute with escalated privileges. Only qualified and authorized individuals must be allowed to obtain access to information system components for purposes of initiating changes, including upgrades and modifications. The operating system or software configuration management utility must enforce control of software installation by users based upon what types of software installations are permitted (e.g., updates and security patches to existing software) and what types of installations are prohibited (e.g., software whose pedigree with regard to being potentially malicious is unknown or suspect) by the organization. Satisfies: SRG-OS-000080-GPOS-00048, SRG-OS-000259-GPOS-00100, SRG-OS-000324-GPOS-00125, SRG-OS-000362-GPOS-00149
Fix
Configure the ACF2 rules for SYS1.LINKLIB limit access to system programmers only and all update and allocate access is logged.
Rating Info
DISA Cat II. NIST impact 3.
Expert Comment
None
ACF2-OS-000230: IBM z/OS DFSMS control data sets must reside on separate storage volumes.
Review the logical parmlib data sets, example: SYS1.PARMLIB(IGDSMSxx), to identify the fully qualified file names for the following SMS data sets: Active Control Data Set (ACDS) Communications Data Set (COMMDS) If the COMMDS and ACDS SMS data sets identified above reside on different volumes, this is not a finding. If the COMMDS and ACDS SMS data sets identified above are collocated on the same volume, this is a finding.
Discussion
Configuration settings are the set of parameters that can be changed in hardware, software, or firmware components of the system that affect the security posture and/or functionality of the system. Security-related parameters are those parameters impacting the security state of the system, including the parameters required to satisfy other security control requirements. Security-related parameters include, for example: registry settings; account, file, directory permission settings; and settings for functions, ports, protocols, services, and remote connections.
Fix
Allocate the primary and backup SMS Control data sets on separate volumes. Source Control Data Set (SCDS) contains a SMS configuration, which defines a storage management policy. Active Control Data Set (ACDS) contains a copy of the most recently activated configuration. All systems in a SMS complex use this configuration to manage storage. Communications Data Set (COMMDS) contains the name of the ACDS containing the currently active storage management policy, the current utilization statistics for each system managed volume, and other system information. The ACDS data set will reside on a different volume than the COMMDS data set. Allocate backup copies of the ADCS and COMMDS data sets on a different shared volume from the primary ACDS and COMMDS data sets.
Rating Info
DISA Cat II. NIST impact 3.
Expert Comment
None
ACF2-OS-000370: IBM z/OS Policy agent must contain a policy that manages excess capacity, bandwidth, or other redundancy to limit the effects of information flooding types of Denial of Service (DoS) attacks.
Examine the Policy Agent policy statements. If it can be determined that there are policy statements that manages excess capacity, this is not a finding.
Discussion
DoS is a condition when a resource is not available for legitimate users. When this occurs, the organization either cannot accomplish its mission or must operate at degraded capacity.
Fix
Develop Policy application and Policy agent to manage excess capacity.
Rating Info
DISA Cat II. NIST impact 3.
Expert Comment
None
ACF2-IC-000040: IBM Integrated Crypto Service Facility (ICSF) Started Task name must be properly identified / defined to the system ACP.
From the ACF command screen enter: SET LID SET VERBOSE LIST IF(MUSASS) LIST IF(STC) If the logonid for the IBM Integrated Crypto Service Facility (ICSF) started task does not include MUSASS and/or NO-SMC, this is a finding.
Discussion
IBM Integrated Crypto Service Facility (ICSF) requires a started task that will be restricted to certain resources, datasets and other system functions. By defining the started task as a userid to the system ACP, It allows the ACP to control the access and authorized users that require these capabilities. Failure to properly control these capabilities, could compromise of the operating system environment, ACP, and customer data.
Fix
Ensure that the started task for IBM Integrated Crypto Service Facility (ICSF) Started Task(s) is properly Identified / defined to the System ACP. If the product requires a Started Task, verify that it is properly defined to the System ACP with the proper attributes. Most installation manuals will indicate how the Started Task is identified and any additional attributes that must be specified. Define the started task userid CSFSTART for IBM Integrated Crypto Service Facility (ICSF). Example: INSERT CSFSTART NAME(STC, ICSF) NO-SMC STC
Rating Info
DISA Cat II. NIST impact 3.
Expert Comment
None
ACF2-OS-000320: IBM z/OS must properly configure CONSOLxx members.
Review each CONSOLxx parmlib member. If the following guidance is true, this is not a finding. The "DEFAULT" statement for each CONSOLxx member specifies "LOGON(REQUIRED)" or "LOGON(AUTO)". The "CONSOLE" statement for each console assigns a unique name using the "NAME" parameter. The "CONSOLE" statement for each console specifies "AUTH(INFO)". Exceptions are the "AUTH" parameter is not valid for consoles defined with "UNIT(PRT)" and specifying "AUTH(MASTER)" is permissible for the system console. Note: The site should be able to determine the system consoles. However, it is imperative that the site adhere to the "DEFAULT" statement requirement.
Discussion
In order to prevent unauthorized connection of devices, unauthorized transfer of information, or unauthorized tunneling (i.e., embedding of data types within data types), organizations must disable or restrict unused or unnecessary physical and logical ports/protocols on information systems. Operating systems are capable of providing a wide variety of functions and services. Some of the functions and services provided by default may not be necessary to support essential organizational operations. Additionally, it is sometimes convenient to provide multiple services from a single component (e.g., VPN and IPS); however, doing so increases risk over limiting the services provided by any one component. To support the requirements and principles of least functionality, the operating system must support the organizational requirements, providing only essential capabilities and limiting the use of ports, protocols, and/or services to only those required, authorized, and approved to conduct official business or to address authorized quality of life issues. MCS consoles can be used to issue operator commands. Failure to properly control access to MCS consoles could result in unauthorized personnel issuing sensitive operator commands. This exposure may threaten the integrity and availability of the operating system environment, and compromise the confidentiality of customer data.
Fix
Configure the "DEFAULT" statement to specify "LOGON(REQUIRED)" so that all operators are required to log on prior to entering z/OS system commands. At the discretion of the ISSO, "LOGON(AUTO)" may be used. If "LOGON(AUTO)" is used assure that the console userids are defined with minimal access. Configure each "CONSOLE" statement to specify an explicit console NAME. And that "AUTH(INFO)" is specified, this also including extended MCS consoles. "AUTH(MASTER)" may be specified for systems console. Note: The site should be able to determine the system consoles. However, it is imperative that the site adhere to the "DEFAULT" statement requirement.
Rating Info
DISA Cat II. NIST impact 3.
Expert Comment
None
ACF2-JS-000020: IBM z/OS JESSPOOL resources must be protected in accordance with security requirements.
From the ACF command screen enter: SET CONTROL(GSO) LIST LIKE(CLASMAP-) {to determine the resource class for JESSPOOL} NOTE: If CLASMAP defines JESSPOOL as anything other than TYPE(SPL), replace SPL below with the appropriate three letters. SET RESOURCE(SPL) LIST LIKE(-) If the following resources are defined to the JESSPOOL resource class (i.e., TYPE(SPL)) with a default access of PREVENT, this is not a finding. localnodeid.- localnodeid.JES2.$TRCLOG.taskid.-.JESTRACE localnodeid.+MASTER+.SYSLOG.jobid.-.SYSLOG These resource rules may be more generic as long as they pertain directly to the JESTRACE and SYSLOG data sets. For example: localnodeid.JES2.-.-.-.JESTRACE localnodeid.+MASTER+.-.-.-.- Review the JES2 parameters to determine the localnodeid by searching for OWNNODE in the NJEDEF statement, and then searching for NODE(nnnn) (where nnnn is the value specified by OWNNODE). The NAME parameter value specified on this NODE statement is the localnodeid. If the following resource is defined to the JESSPOOL resource class (i.e., TYPE(SPL)) with a default access of READ, this is not a finding. localnodeid.jesid.$JESNEWS.taskid.Dnewslvl.JESNEWS jesid The logonid associated with your JES2 system. NOTE: This resource rule may be more generic as long as it pertains directly to the JESNEWS data set. For example: localnodeid.jesid.$JESNEWS.-.-.JESNEWS
Discussion
To mitigate the risk of unauthorized access to sensitive information by entities that have been issued certificates by DoD-approved PKIs, all DoD systems (e.g., web servers and web portals) must be properly configured to incorporate access control methods that do not rely solely on the possession of a certificate for access. Successful authentication must not automatically give an entity access to an asset or security boundary. Authorization procedures and controls must be implemented to ensure each authenticated entity also has a validated and current authorization. Authorization is the process of determining whether an entity, once authenticated, is permitted to access a specific asset. Information systems use access control policies and enforcement mechanisms to implement this requirement. Access control policies include: identity-based policies, role-based policies, and attribute-based policies. Access enforcement mechanisms include: access control lists, access control matrices, and cryptography. These policies and mechanisms must be employed by the application to control access between users (or processes acting on behalf of users) and objects (e.g., devices, files, records, processes, programs, and domains) in the information system.
Fix
NOTE: If CLASMAP defines JESSPOOL as anything other than TYPE(SPL), replace SPL below with the appropriate three letters. Configure the CLASMAP record to define the JESSPOOL resource class. Example: SHOW CLASMAP The following resources are defined to the JESSPOOL resource class (i.e., TYPE(SPL)) with a default access of PREVENT: localnodeid.- localnodeid.JES2.$TRCLOG.taskid.-.JESTRACE localnodeid.+MASTER+.SYSLOG.jobid.-.SYSLOG Example: $KEY(localnodeid) TYPE(SPL) - UID(*) PREVENT These resource rules may be more generic as long as they pertain directly to the JESTRACE and SYSLOG data sets. For example: localnodeid.JES2.-.-.-.JESTRACE localnodeid.+MASTER+.-.-.-.- Review the JES2 parameters to determine the localnodeid by searching for OWNNODE in the NJEDEF statement, and then searching for NODE(nnnn) (where nnnn is the value specified by OWNNODE). The NAME parameter value specified on this NODE statement is the localnodeid. The following resource is defined to the JESSPOOL resource class (i.e., TYPE(SPL)) with a default access of READ: localnodeid.jesid.$JESNEWS.taskid.Dnewslvl.JESNEWS jesid The logonid associated with your JES2 system. This resource rule may be more generic as long as it pertains directly to the JESNEWS data set. For example: localnodeid.jesid.$JESNEWS.-.-.JESNEWS
Rating Info
DISA Cat II. NIST impact 3.
Expert Comment
None
ACF2-ES-000260: CA-ACF2 must limit Write or greater access to SYS1.IMAGELIB to system programmers.
Execute a data set list of access for SYS1.IMAGELIB. If the following guidance is true, this is not a finding. The ACP data set rules for SYS1.IMAGELIB allow inappropriate access. The ACP data set rules for SYS1.IMAGELIB do not restrict WRITE and/or ALLOCATE access to only systems programming personnel. The ACP data set rules for SYS1.IMAGELIB do not specify that all (i.e., failures and successes) WRITE and/or ALLOCATE access will be logged.
Discussion
To mitigate the risk of unauthorized access to sensitive information by entities that have been issued certificates by DoD-approved PKIs, all DoD systems (e.g., web servers and web portals) must be properly configured to incorporate access control methods that do not rely solely on the possession of a certificate for access. Successful authentication must not automatically give an entity access to an asset or security boundary. Authorization procedures and controls must be implemented to ensure each authenticated entity also has a validated and current authorization. Authorization is the process of determining whether an entity, once authenticated, is permitted to access a specific asset. Information systems use access control policies and enforcement mechanisms to implement this requirement. Access control policies include: identity-based policies, role-based policies, and attribute-based policies. Access enforcement mechanisms include: access control lists, access control matrices, and cryptography. These policies and mechanisms must be employed by the application to control access between users (or processes acting on behalf of users) and objects (e.g., devices, files, records, processes, programs, and domains) in the information system. This requirement applies to operating systems with software libraries that are accessible and configurable, as in the case of interpreted languages. Software libraries also include privileged programs which execute with escalated privileges. Only qualified and authorized individuals must be allowed to obtain access to information system components for purposes of initiating changes, including upgrades and modifications. Satisfies: SRG-OS-000080-GPOS-00048, SRG-OS-000259-GPOS-00100, SRG-OS-000324-GPOS-00125
Fix
Configure WRITE and/or ALLOCATE access to SYS1.IMAGELIB to be limited to system programmers only and all update and allocate access is logged. Review access authorization to critical system files. Evaluate the impact of correcting the deficiency. Develop a plan of action and implement the changes as required to protect SYS1.IMAGELIB. SYS1.IMAGELIB is automatically APF-authorized. This data set contains modules, images, tables, and character sets which are essential to system print services.
Rating Info
DISA Cat I. NIST impact 4.
Expert Comment
None
ACF2-ES-000170: CA-ACF2 must limit access to System page data sets (i.e., PLPA, COMMON, and LOCALx) to system programmers.
Execute a data set list of access for System page data sets (i.e., PLPA, COMMON, and LOCALx). If the ESM data set rules for System page data sets (i.e., PLPA, COMMON, and LOCALx) do not restrict access to only systems programming personnel, this is a finding. If ESM data set rules for system page data sets (PLPA, COMMON, and LOCAL) restrict auditors to READ only, this is not a finding.
Discussion
To mitigate the risk of unauthorized access to sensitive information by entities that have been issued certificates by DoD-approved PKIs, all DoD systems (e.g., web servers and web portals) must be properly configured to incorporate access control methods that do not rely solely on the possession of a certificate for access. Successful authentication must not automatically give an entity access to an asset or security boundary. Authorization procedures and controls must be implemented to ensure each authenticated entity also has a validated and current authorization. Authorization is the process of determining whether an entity, once authenticated, is permitted to access a specific asset. Information systems use access control policies and enforcement mechanisms to implement this requirement. Access control policies include: identity-based policies, role-based policies, and attribute-based policies. Access enforcement mechanisms include: access control lists, access control matrices, and cryptography. These policies and mechanisms must be employed by the application to control access between users (or processes acting on behalf of users) and objects (e.g., devices, files, records, processes, programs, and domains) in the information system. Satisfies: SRG-OS-000080-GPOS-00048, SRG-OS-000324-GPOS-00125
Fix
Configure the ESM data set rules for system page data sets (PLPA, COMMON, and LOCAL) to restrict access to only systems programming personnel. Auditors may be allowed READ Access as approved by the ISSM.
Rating Info
DISA Cat II. NIST impact 3.
Expert Comment
None
ACF2-OS-000310: Duplicated IBM z/OS sensitive utilities and/or programs must not exist in APF libraries.
From an ISPF Command line enter: TSO ISRDDN APF An APF List results On the command line enter: DUPlicates (make sure there is appropriate access, if not you may receive insufficient access errors) If any of the list of Sensitive Utilities exist in the duplicate APF modules return, this is a finding. The following list contains Sensitive Utilities that will be checked. AHLGTF AMASPZAP AMAZAP AMDIOCP AMZIOCP BLSROPTR CSQJU003 CSQJU004 CSQUCVX CSQUTIL CSQ1LOGP DEBE DITTO FDRZAPOP GIMSMP HHLGTF ICKDSF ICPIOCP IDCSC01 IEHINITT IFASMFDP IGWSPZAP IHLGTF IMASPZAP IND$FILE IOPIOCP IXPIOCP IYPIOCP IZPIOCP WHOIS L052INIT TMSCOPY TMSFORMT TMSLBLPR TMSMULV TMSREMOV TMSTPNIT TMSUDSNB
Discussion
Removal of unneeded or non-secure functions, ports, protocols, and services mitigate the risk of unauthorized connection of devices, unauthorized transfer of information, or other exploitation of these resources. The organization must perform a periodic scan/review of the application (as required by CCI-000384) and disable functions, ports, protocols, and services deemed to be unneeded or non-secure.
Fix
Review and ensure that duplicate sensitive utility(ies) and/or program(s) do not exist in APF-authorized libraries. Identify all versions of the sensitive utilities contained in APF-authorized libraries listed in the above check. In cases where duplicates exist, ensure no exposure has been created and written justification has been filed with the ISSO. Comparisons among all the APF libraries will be done to ensure that an exposure is not created by the existence of identically named modules. Address any sensitive utility concerns so that the function can be restricted as required.
Rating Info
DISA Cat II. NIST impact 3.
Expert Comment
None
ACF2-UT-000050: IBM z/OS UNIX Telnet Server Startup parameters must be properly specified to display the banner.
From the ISPF Command Shell enter: ISHELL Enter /etc/ for a pathname; a CD /etc/ may need to be issued. select FILE NAME inetd.conf If Option -h is included on the otelnetd command, this is a finding.
Discussion
Display of a standardized and approved use notification before granting access to the publicly accessible operating system ensures privacy and security notification verbiage used is consistent with applicable federal laws, Executive Orders, directives, policies, regulations, standards, and guidance. System use notifications are required only for access via logon interfaces with human users and are not required when such human interfaces do not exist.
Fix
Configure the startup parameters in the inetd.conf file for otelnetd to exclude option -h. Note: -h indicates that the logon banner should not be displayed.
Rating Info
DISA Cat II. NIST impact 3.
Expert Comment
None
ACF2-CE-000020: IBM z/OS must not use Expired Digital Certificates.
Execute the CA-ACF2 SAFCRRPT using the following as SYSIN input RECORDID(-) DETAIL FIELDS(ISSUER SUBJECT ACTIVE EXPIRE TRUST) If no certificate information is found, this is not a finding. NOTE: Certificates are only valid when their Status is TRUST. Therefore, you may ignore certificates with the NOTRUST status during the following checks. If the digital certificate information indicates that the issuer's distinguished name leads to a DoD PKI Root Certificate Authority or External Certification Authority (ECA), this is not a finding. Reference the DoD Cyber Exchange website for complete information as to which certificates are acceptable (https://cyber.mil/pki-pke/interoperability/). Examples of an acceptable DoD CA are: DoD PKI Class 3 Root CA DoD PKI Med Root CA
Discussion
Without path validation, an informed trust decision by the relying party cannot be made when presented with any certificate not already explicitly trusted. A trust anchor is an authoritative entity represented via a public key and associated data. It is used in the context of public key infrastructures, X.509 digital certificates, and DNSSEC. When there is a chain of trust, usually the top entity to be trusted becomes the trust anchor; it can be, for example, a Certification Authority (CA). A certification path starts with the subject certificate and proceeds through a number of intermediate certificates up to a trusted root certificate, typically issued by a trusted CA. This requirement verifies that a certification path to an accepted trust anchor is used for certificate validation and that the path includes status information. Path validation is necessary for a relying party to make an informed trust decision when presented with any certificate not already explicitly trusted. Status information for certification paths includes certificate revocation lists or online certificate status protocol responses. Validation of the certificate status information is out of scope for this requirement.
Fix
If the certificate is a user or device certificate with a status of trust, follow procedures to obtain a new certificate or re-key certificate. If it is an expired CA certificate remove it.
Rating Info
DISA Cat II. NIST impact 3.
Expert Comment
None
ACF2-ES-000690: ACF2 BACKUP GSO record must be defined with a TIME value specifies greater than 00 unless the database is shared and backed up on another system.
From the ACF command screen enter: SET CONTROL(GSO) LIST LIKE(BACKUP-) If the GSO BACKUP record values conform to the following requirements, this is not a finding. Example: CPUID() PRISPACE(5) SECSPACE(5) STRING(S ACFBKUP) TIME(00:01) WORKUNIT(VIO) If there is any deviation from the above requirements in the GSO BACKUP record values, this is a finding.
Discussion
Configuring the operating system to implement organization-wide security implementation guides and security checklists ensures compliance with federal standards and establishes a common security baseline across DoD that reflects the most restrictive security posture consistent with operational requirements. Configuration settings are the set of parameters that can be changed in hardware, software, or firmware components of the system that affect the security posture and/or functionality of the system. Security-related parameters are those parameters impacting the security state of the system, including the parameters required to satisfy other security control requirements. Security-related parameters include, for example: registry settings; account, file, directory permission settings; and settings for functions, ports, protocols, services, and remote connections.
Fix
Configure the BACKUP GSO value to specify a time field and Time(00:00 ) is not specified unless the database is shared and backed up on another system. CPUID() PRISPACE(5) SECSPACE(5) STRING(S ACFBKUP) TIME(00:01) WORKUNIT(VIO) Example: SET C(GSO) INSERT BACKUP CPUID() PRISPACE(5) SECSPACE(5) STRING(S ACFBKUP) TIME(00:01) WORKUNIT(VIO) F ACF2,REFRESH(BACKUP)
Rating Info
DISA Cat II. NIST impact 3.
Expert Comment
None
ACF2-ES-000820: CA-ACF2 must enforce password complexity by requiring that at least one special character be used.
From an ACF command screen enter: SET CONTROL(GSO) LIST PSWD If PSWDPLST is coded as defined in CA ACF2 for z/OS Administration Guide, this is not a finding.
Discussion
Use of a complex password helps to increase the time and resources required to compromise the password. Password complexity or strength is a measure of the effectiveness of a password in resisting attempts at guessing and brute-force attacks. Password complexity is one factor in determining how long it takes to crack a password. The more complex the password, the greater the number of possible combinations that need to be tested before the password is compromised. Special characters are those characters that are not alphanumeric. Examples include: ~ ! @ # $ % ^ *.
Fix
Configure Password option PSWDPLST as defined in CA ACF2 for z/OS Administration Guide.
Rating Info
DISA Cat II. NIST impact 3.
Expert Comment
None
ACF2-ES-000390: ACF2 PPGM GSO record value must specify protected programs that are only executed by privileged users.
From the ACF command screen enter: SET CONTROL(GSO) LIST LIKE(PPGM-) Refer to the table of Sensitive Utilities resources and/or generic equivalent as detailed in the table. If all applicable programs or their generic equivalent referenced below are represented by GSO PPGM record values, this is not a finding. Sensitive Utility Controls Program Product Function AHLGTF z/OS System Activity Tracing HHLGTF IHLGTF ICPIOCP z/OS System Configuration IOPIOCP IXPIOCP IYPIOCP IZPIOCP BLSROPTR z/OS Data Management DEBE OS/DEBE Data Management DITTO OS/DITTO Data Management FDRZAPOP FDR Product Internal Modification GIMSMP SMP/E Change Management Product ICKDSF z/OS DASD Management IDCSC01 z/OS IDCAMS Set Cache Module IEHINITT z/OS Tape Management IFASMFDP z/OS SMF Data Dump Utility IND$FILE z/OS PC to Mainframe File Transfer (Applicable only for classified systems) CSQJU003 IBM WebSphereMQ CSQJU004 CSQUCVX CSQ1LOGP CSQUTIL WHOIS z/OS Share MOD to identify user name from USERID. Restricted to data center personnel only.
Discussion
Preventing non-privileged users from executing privileged functions mitigates the risk that unauthorized individuals or processes may gain unnecessary access to information or privileges. Privileged functions include, for example, establishing accounts, performing system integrity checks, or administering cryptographic key management activities. Non-privileged users are individuals that do not possess appropriate authorizations. Circumventing intrusion detection and prevention mechanisms or malicious code protection mechanisms are examples of privileged functions that require protection from non-privileged users.
Fix
Configure the PPGM GSO value indicating protected programs that are only executed by privileged users in the table below. Sensitive Utility Controls Program Product Function AHLGTF z/OS System Activity Tracing HHLGTF IHLGTF ICPIOCP z/OS System Configuration IOPIOCP IXPIOCP IYPIOCP IZPIOCP BLSROPTR z/OS Data Management DEBE OS/DEBE Data Management DITTO OS/DITTO Data Management FDRZAPOP FDR Product Internal Modification GIMSMP SMP/E Change Management Product ICKDSF z/OS DASD Management IDCSC01 z/OS IDCAMS Set Cache Module IEHINITT z/OS Tape Management IFASMFDP z/OS SMF Data Dump Utility IND$FILE z/OS PC to Mainframe File Transfer (Applicable only for classified systems) CSQJU003 IBM WebSphereMQ CSQJU004 CSQUCVX CSQ1LOGP CSQUTIL WHOIS z/OS Share MOD to identify user name from USERID. Restricted to data center personnel only. Define protected programs that can only be executed by privileged users. PGM MASK(pgm mask1, ...,pgm-mask255) Example: SET C(GSO) INSERT PPGM PGM-MASK(<program name or generic equivalent>) F ACF2,REFRESH(PPGM)
Rating Info
DISA Cat II. NIST impact 3.
Expert Comment
None
ACF2-ES-000480: CA-ACF2 must limit Write or greater access to libraries that contain PPT modules to system programmers only.
Review program entries in the IBM Program Properties Table (PPT). You may use a third-party product to examine these entries however, to determine program entries issue the following command from an ISPF command line: TSO ISRDDN LOAD IEFSDPPT Press Enter For each module identified in the 'eyecatcher' : If all of the following are untrue, this is not a finding. If any of the following is true, this is a finding. -The ESM data set rules for libraries that contain PPT modules do not restrict UPDATE and ALLOCATE access to only z/OS systems programming personnel. -The ESM data set rules for libraries that contain PPT modules do not specify that all UPDATE and ALLOCATE access will be logged.
Discussion
If the operating system were to allow any user to make changes to software libraries, then those changes might be implemented without undergoing the appropriate testing and approvals that are part of a robust change management process. This requirement applies to operating systems with software libraries that are accessible and configurable, as in the case of interpreted languages. Software libraries also include privileged programs which execute with escalated privileges. Only qualified and authorized individuals must be allowed to obtain access to information system components for purposes of initiating changes, including upgrades and modifications. Satisfies: SRG-OS-000080-GPOS-00048, SRG-OS-000259-GPOS-00100, SRG-OS-000324-GPOS-00125
Fix
Configure the Update and Allocate access to libraries containing PPT modules to be limited to system programmers only and all Update and Allocate access is logged.
Rating Info
DISA Cat III. NIST impact 2.
Expert Comment
None
ACF2-UT-000040: IBM z/OS UNIX Telnet Server warning banner must be properly specified.
From the ISPF Command Shell enter: ISHELL Enter /etc/ for a pathname; a CD /etc/ may need to be issued. select FILE NAME inetd.conf If Option -D login is included on the otelnetd command, this is not a finding. If Option -c 900 is included on the otelnetd command, this is not a finding. NOTE: "900" indicates a session timeout value of "15" minutes and is currently the maximum value allowed.
Discussion
Display of a standardized and approved use notification before granting access to the publicly accessible operating system ensures privacy and security notification verbiage used is consistent with applicable federal laws, Executive Orders, directives, policies, regulations, standards, and guidance. System use notifications are required only for access via logon interfaces with human users and are not required when such human interfaces do not exist.
Fix
Configure the startup parameters in the inetd.conf file for otelnetd to conform to the specifications below. The otelnetd startup command includes the options -D login and -c 900, where: -D login indicates that messages should be written to the syslogd facility for login and logout activity. -c 900 indicates that the Telnet session should be terminated after "15" minutes of inactivity. NOTE: "900" is the maximum value; any value between "1" and "900" is acceptable.
Rating Info
DISA Cat II. NIST impact 3.
Expert Comment
None
ACF2-ES-000500: The CA-ACF2 LOGONID with the REFRESH attribute must have procedures for utilization.
From the ACF Command screen enter: SET LID LIST IF(REFRESH) If procedures exist to utilize the logonid with the REFRESH attribute to refresh ACF2 global options, this is not a finding. Example of a suggested procedure follows: When the ISSO determines it necessary to refresh the ACF2 global options, the ISSO will do the following: -Activate the REFRESH ID with the following setting(s): NOSUSPEND NOPSWD EXP PASSWORD(new password) -Instruct Operations to perform the REFRESH. -Deactivate the REFRESH ID with the following setting: SUSPEND If no procedures exist in accordance with the STIG requirements to utilize the logonid with the REFRESH attribute to refresh ACF2 global options, this is a finding.
Discussion
Configuring the operating system to implement organization-wide security implementation guides and security checklists ensures compliance with federal standards and establishes a common security baseline across DoD that reflects the most restrictive security posture consistent with operational requirements.
Fix
Review security procedures for defining LOGONIDs and develop documentation of requirements for the LOGONID associated with the REFRESH attribute. Example of a suggested procedure follows: When the ISSO determines it necessary to refresh the ACF2 global options, the ISSO will do the following: -Activate the required REFRESH ID with the following setting(s): NOSUSPEND NOPSWD EXP PASSWORD(new password) -Instruct Operations to perform the REFRESH using the newly activated REFRESH ID. -After refresh is completed. -Deactivate the REFRESH ID with the following setting: SUSPEND This procedure should be documented in the Site Security Plan.
Rating Info
DISA Cat II. NIST impact 3.
Expert Comment
None
ACF2-US-000210: IBM z/OS UNIX groups must be defined with a unique GID.
From an ACF Command screen enter: SET PROFILE(GROUP) DIVISION(OMVS) LIST LIKE(-) If each of the definitions have a unique GID, this is not a finding.
Discussion
To assure accountability and prevent unauthenticated access, organizational users must be identified and authenticated to prevent potential misuse and compromise of the system. Organizational users include organizational employees or individuals the organization deems to have equivalent status of employees (e.g., contractors). Organizational users (and processes acting on behalf of users) must be uniquely identified and authenticated to all accesses, except for the following: 1) Accesses explicitly identified and documented by the organization. Organizations document specific user actions that can be performed on the information system without identification or authentication; and 2) Accesses that occur through authorized use of group authenticators without individual authentication. Organizations may require unique identification of individuals in group accounts (e.g., shared privilege accounts) or for detailed accountability of individual activity.
Fix
Define each UNIX group with a unique GID.
Rating Info
DISA Cat II. NIST impact 3.
Expert Comment
None
ACF2-ES-000850: ACF2 PSWD GSO record value must be set to require at least one numeric character be used.
From an ACF command screen enter: SET CONTROL(GSO) LIST PSWD If "PSWDALPH" is coded, this is not a finding.
Discussion
Use of a complex password helps to increase the time and resources required to compromise the password. Password complexity, or strength, is a measure of the effectiveness of a password in resisting attempts at guessing and brute-force attacks. Password complexity is one factor of several that determines how long it takes to crack a password. The more complex the password, the greater the number of possible combinations that need to be tested before the password is compromised.
Fix
Configure the Password options to include "PSWDALPH".
Rating Info
DISA Cat II. NIST impact 3.
Expert Comment
None
ACF2-TC-000010: IBM z/OS PROFILE.TCPIP configuration statements for the TCP/IP stack must be coded properly.
Refer to the Profile configuration file specified on the PROFILE DD statement in the TCPIP started task JCL. NOTE: If the INCLUDE statement is coded in the TCP/IP Profile configuration file, the data set specified on this statement must be checked for the following items as well. If the SMFPARMS statement is not coded or commented out, this is not a finding. If the DELETE statement is not coded or commented out for production system, this is not a finding. If the SMFCONFIG statement is coded with (at least) the FTPCLIENT and TN3270CLIENT operands, this is not a finding. If the TCPCONFIG and UDPCONFIG statements are coded with (at least) the RESTRICTLOWPORTS operand, this is not a finding. If the TCPCONFIG does not have the TTLS statement coded, this is a finding. NOTE: If the INCLUDE statement is coded, the data set specified will be checked for access authorization compliance.
Discussion
Remote access services, such as those providing remote access to network devices and information systems, which lack automated monitoring capabilities, increase risk and make remote user access management difficult at best. Remote access is access to DoD nonpublic information systems by an authorized user (or an information system) communicating through an external, non-organization-controlled network. Remote access methods include, for example, dial-up, broadband, and wireless. Automated monitoring of remote access sessions allows organizations to detect cyber attacks and also ensure ongoing compliance with remote access policies by auditing connection activities of remote access capabilities, such as Remote Desktop Protocol (RDP), on a variety of information system components (e.g., servers, workstations, notebook computers, smartphones, and tablets).
Fix
Configure the statements in the PROFILE.TCPIP file to conform to the specifications below: NOTE: If the INCLUDE statement is coded in the TCP/IP Profile configuration file, the data set specified on this statement must be checked for the following items as well. The SMFPARMS statement is not coded or commented out. The DELETE statement is not coded or commented out for production systems. The SMFCONFIG statement is coded with (at least) the FTPCLIENT and TN3270CLIENT operands. The TCPCONFIG and UDPCONFIG statements are coded with (at least) the RESTRICTLOWPORTS operand. TCPCONFIG coded with TTLS - Specifies that the AT-TLS function is activated for the TCP/IP stack. The AT-TLS function provides invocation of System SSL in the TCP transport layer of the stack. Note: If AT-TLS is enabled, you must activate the SERVAUTH class, define the INITSTACK resource profile, and permit users to it. NOTE: If the INCLUDE statement is coded, the data set specified will be checked for access authorization compliance.
Rating Info
DISA Cat II. NIST impact 3.
Expert Comment
None
ACF2-ES-000440: IBM z/OS SYS1.PARMLIB must be properly protected.
Execute a data set list of access to SYS1.PARMLIB. If the ACF2 data set rules for SYS1.PARMLIB allow inappropriate (e.g., global READ) access, this is a finding. If data set rules for SYS1.PARMLIB do not restrict READ, WRITE, and ALLOCATE access to only systems programming personnel, this is a finding. If data set rules for SYS1.PARMLIB do not restrict READ and WRITE access to only domain-level security administrators, this is a finding. If data set rules for SYS1.PARMLIB do not restrict READ access to only system-level Started Tasks, authorized Data Center personnel, and auditors, this is a finding. If data set rules for SYS1.PARMLIB do not specify that all (i.e., failures and successes) WRITE and/or ALLOCATE access will be logged, this is a finding.
Discussion
To mitigate the risk of unauthorized access to sensitive information by entities that have been issued certificates by DoD-approved PKIs, all DoD systems (e.g., web servers and web portals) must be properly configured to incorporate access control methods that do not rely solely on the possession of a certificate for access. Successful authentication must not automatically give an entity access to an asset or security boundary. Authorization procedures and controls must be implemented to ensure each authenticated entity also has a validated and current authorization. Authorization is the process of determining whether an entity, once authenticated, is permitted to access a specific asset. Information systems use access control policies and enforcement mechanisms to implement this requirement. Access control policies include: identity-based policies, role-based policies, and attribute-based policies. Access enforcement mechanisms include: access control lists, access control matrices, and cryptography. These policies and mechanisms must be employed by the application to control access between users (or processes acting on behalf of users) and objects (e.g., devices, files, records, processes, programs, and domains) in the information system. Without the capability to restrict which roles and individuals can select which events are audited, unauthorized personnel may be able to prevent the auditing of critical events. Misconfigured audits may degrade the system's performance by overwhelming the audit log. Misconfigured audits may also make it more difficult to establish, correlate, and investigate the events relating to an incident or identify those responsible for one. Satisfies: SRG-OS-000063-GPOS-00032, SRG-OS-000080-GPOS-00048, SRG-OS-000259-GPOS-00100, SRG-OS-000324-GPOS-00125, SRG-OS-000337-GPOS-00129, SRG-OS-000362-GPOS-00149
Fix
Configure access rules for SYS1.PARMLIB as follows: Systems programming personnel will be authorized to update and alter the SYS1.PARMLIB concatenation. Domain level security administrators can be authorized to update the SYS1.PARMLIB concatenation. System Level Started Tasks, authorized Data Center personnel, and auditor can be authorized read access by the ISSO. All update and alter access is logged.
Rating Info
DISA Cat I. NIST impact 4.
Expert Comment
None
ACF2-ES-000320: CA-ACF2 must limit Write or greater access to SYS1.SVCLIB to system programmers only.
Execute a data set list of access for SYS1.SVCLIB. If all of the following are true, this is not a finding. If any of the following are untrue, this is a finding. ACF2 data set rules for SYS1.SVCLIB restrict WRITE and/or ALLOCATE access to only z/OS systems programming personnel. ACF2 data set rules for SYS1.SVCLIB specify that all (i.e., failures and successes) WRITE and/or ALLOCATE access will be logged.
Discussion
To mitigate the risk of unauthorized access to sensitive information by entities that have been issued certificates by DoD-approved PKIs, all DoD systems (e.g., web servers and web portals) must be properly configured to incorporate access control methods that do not rely solely on the possession of a certificate for access. Successful authentication must not automatically give an entity access to an asset or security boundary. Authorization procedures and controls must be implemented to ensure each authenticated entity also has a validated and current authorization. Authorization is the process of determining whether an entity, once authenticated, is permitted to access a specific asset. Information systems use access control policies and enforcement mechanisms to implement this requirement. Access control policies include: identity-based policies, role-based policies, and attribute-based policies. Access enforcement mechanisms include: access control lists, access control matrices, and cryptography. These policies and mechanisms must be employed by the application to control access between users (or processes acting on behalf of users) and objects (e.g., devices, files, records, processes, programs, and domains) in the information system. Satisfies: SRG-OS-000080-GPOS-00048, SRG-OS-000259-GPOS-00100, SRG-OS-000324-GPOS-00125
Fix
Configure update and allocate access to SYS1.SVCLIB to be limited to system programmers only and all Update and Allocate access is logged and reviewed. Evaluate the impact of correcting the deficiency. Develop a plan of action and implement the changes for SYS1.SVCLIB. SYS1.SVCLIB contains SVCs and I/O appendages as such: they are very powerful and will be strictly controlled to avoid compromising system integrity.
Rating Info
DISA Cat I. NIST impact 4.
Expert Comment
None
ACF2-OS-000010: The IBM z/OS BPX.SMF resource must be properly configured.
Review the FACILITY resource class for BPX.SMF. If the ACF2 rules are as follows, this is not a finding. BPX.SMF.119.94 - READ allowed for users running the ssh, sftp, or scp client commands. BPX.SMF.119.96 - READ allowed for users running the scp or sftp-server server commands. BPX.SMF.119.97 - READ allowed for users running the scp or sftp client commands. The following profile grants the permitted users the authority to write or test for any SMF record being recorded. Access should be permitted as follows: BPX.SMF - READ access only when documented and justified in Site Security Plan. Documentation should include a reason why a more specific profile is not acceptable.
Discussion
Remote access services, such as those providing remote access to network devices and information systems, which lack automated monitoring capabilities, increase risk and make remote user access management difficult at best. Remote access is access to DoD nonpublic information systems by an authorized user (or an information system) communicating through an external, non-organization-controlled network. Remote access methods include, for example, dial-up, broadband, and wireless. Automated monitoring of remote access sessions allows organizations to detect cyber attacks and also ensure ongoing compliance with remote access policies by auditing connection activities of remote access capabilities, such as Remote Desktop Protocol (RDP), on a variety of information system components (e.g., servers, workstations, notebook computers, smartphones, and tablets).
Fix
Configure Facility resource class for BPX.SMF as follows: BPX.SMF.119.94 - READ allowed for users running the ssh, sftp, or scp client commands. BPX.SMF.119.96 - READ allowed for users running the scp or sftp-server server commands. BPX.SMF.119.97 - READ allowed for users running the scp or sftp client commands. The following profile grants the permitted users the authority to write or test for any SMF record being recorded. Access should be permitted as follows: BPX.SMF - READ access only when documented and justified in Site Security Plan. Documentation should include a reason why a more specific profile is not acceptable.
Rating Info
DISA Cat II. NIST impact 3.
Expert Comment
None
ACF2-US-000140: IBM z/OS UNIX OMVS parameters in PARMLIB must be properly specified.
Refer to the IEASYS00 member of SYS1.PARMLIB. If the parameter is specified as OMVS=xx or OMVS=(xx,xx,...) in the IEASYSxx member, this is not a finding. If the OMVS statement is not specified, OMVS=DEFAULT is used. In minimum mode there is no access to permanent file systems or to the shell, and IBM's Communication Server TCP/IP will not run.
Discussion
Configuring the operating system to implement organization-wide security implementation guides and security checklists ensures compliance with federal standards and establishes a common security baseline across DoD that reflects the most restrictive security posture consistent with operational requirements.
Fix
Configure the settings in PARMLIB and /etc for z/OS UNIX security parameters with values that conform to the specifications below: The parameter is specified as OMVS=xx or OMVS=(xx,xx,...) in the IEASYSxx member. Note: If the OMVS statement is not specified, OMVS=DEFAULT is used. In minimum mode there is no access to permanent file systems or to the shell, and IBM's Communication Server TCP/IP will not run.
Rating Info
DISA Cat II. NIST impact 3.
Expert Comment
None
ACF2-ES-000640: ACF2 LOGONIDs with the NON-CNCL attribute specified in the associated LOGONID record must be listed as trusted and must be specifically approved.
From the ACF command screen enter: SET LID SET VERBOSE LIST IF(NON-CNCL) If only logonids associated with trusted STCs have the NON-CNCL attribute specified, this is not a finding. TRUSTED STCs: STCs that are listed as z/OS started tasks and address spaces in the IBM z/OS MVS Initialization and Tuning Reference. Guidelines for reference: Assign the TRUSTED attribute when one of the following conditions applies: -The started procedure or address space creates or accesses a wide variety of unpredictably named data sets within your installation. -Insufficient authority to an accessed resource might risk an unsuccessful IPL or other system problem. -Avoid assigning TRUSTED to a z/OS started procedure or address space unless it is listed here or you are instructed to do so by the product documentation. Additionally external security managers are candidates for trusted attribute. Any other started tasks not listed or not covered by the guidelines are a finding unless approval by the Authorizing Official AO.
Discussion
Activity under unusual conditions can indicate hostile activity. For example, what is normal activity during business hours can indicate hostile activity if it occurs during off hours. Depending on mission needs and conditions, account usage restrictions based on conditions and circumstances may be critical to limit access to resources and data to comply with operational or mission access control requirements. Thus, the operating system must be configured to enforce the specific conditions or circumstances under which organization-defined accounts can be used (e.g., by restricting usage to certain days of the week, time of day, or specific durations of time).
Fix
Review all LOGONIDs with the NON-CNCL attribute. Ensure that only STCs in the trusted list in the IBM z/OS MVS Initialization and Tuning Reference have been granted this authority. Evaluate the impact of correcting the deficiency. Develop a plan of action and implement the changes. Trusted STCs: While the actual list may vary based on local site requirements and software configuration, the started tasks listed in the IBM z/OS MVS Initialization and Tuning Reference is an approved list of started tasks that may be considered trusted started procedures. Guidelines for reference: Assign the TRUSTED attribute when one of the following conditions applies: -The started procedure or address space creates or accesses a wide variety of unpredictably named data sets within your installation. -Insufficient authority to an accessed resource might risk an unsuccessful IPL or other system problem. -Avoid assigning TRUSTED to a z/OS started procedure or address space unless it is listed here or you are instructed to do so by the product documentation. Additionally external security managers are candidates for trusted attribute. Any other started tasks not listed or not covered by the guidelines are a finding unless approval by the Authorizing Official AO. These STCs will be given the following attribute to facilitate access while logging any accesses they would not ordinarily be granted by the access rule sets: NON-CNCL Example: SET LID CHANGE logonid STC NON-CNCL
Rating Info
DISA Cat II. NIST impact 3.
Expert Comment
None
ACF2-ES-000080: CA-ACF2 NJE GSO record value must indicate validation options that apply to jobs submitted through a network job entry subsystem (JES2, JES3, RSCS).
From the ACF input screen enter: SET CONTROL(GSO) LIST LIKE(NJE-) If the GSO NJE record values conform to the following requirements, this is not a finding. Specifies ACF2 validation options that apply to jobs submitted through a network job entry subsystem (JES2, JES3, RSCS). DFTLID() INHERIT NODEMASK(-) ENCRYPT VALIN(YES) NOVALOUT NOTE: For NJE nodes that are incompatible with the XDES algorithm, discrete NJE records will be created with NOENCRYPT. NOTE: Local changes will be documented in writing with supporting documentation.
Discussion
To mitigate the risk of unauthorized access to sensitive information by entities that have been issued certificates by DoD-approved PKIs, all DoD systems (e.g., web servers and web portals) must be properly configured to incorporate access control methods that do not rely solely on the possession of a certificate for access. Successful authentication must not automatically give an entity access to an asset or security boundary. Authorization procedures and controls must be implemented to ensure each authenticated entity also has a validated and current authorization. Authorization is the process of determining whether an entity, once authenticated, is permitted to access a specific asset. Information systems use access control policies and enforcement mechanisms to implement this requirement. Access control policies include: identity-based policies, role-based policies, and attribute-based policies. Access enforcement mechanisms include: access control lists, access control matrices, and cryptography. These policies and mechanisms must be employed by the application to control access between users (or processes acting on behalf of users) and objects (e.g., devices, files, records, processes, programs, and domains) in the information system.
Fix
Configure ACF2 validation options that apply to jobs submitted through a network job entry subsystem (JES2, JES3, RSCS) as follows: DFTLID() INHERIT NODEMASK(-) ENCRYPT VALIN(YES) NOVALOUT NOTE: For NJE nodes that are incompatible with the XDES algorithm, discrete NJE records will be created with NOENCRYPT. NOTE: Local changes will be justified in writing with supporting documentation.
Rating Info
DISA Cat II. NIST impact 3.
Expert Comment
None
ACF2-UT-000030: IBM z/OS UNIX Telnet Server etc/banner file must have the Standard Mandatory DoD Notice and Consent Banner.
From UNIX System Services ISPF Shell enter path "/etc/otelnet/banner/" If this file does not contain the banner below, check the UNIX System Services ISPF Shell path /etc/banner If neither file contains the banner below this is a finding. If the banner below is contained in either this is not a finding. This banner is mandatory and deviations are not permitted except as authorized in writing by the DoD Chief Information Officer. The thrust of this new policy is to make it clear that there is no expectation of privacy when using DoD information systems and all use of DoD information systems is subject to searching, auditing, inspecting, seizing, and monitoring, even if some personal use of a system is permitted: STANDARD MANDATORY DOD NOTICE AND CONSENT BANNER You are accessing a U.S. Government (USG) Information System (IS) that is provided for USG-authorized use only. By using this IS (which includes any device attached to this IS), you consent to the following conditions: -The USG routinely intercepts and monitors communications on this IS for purposes including, but not limited to, penetration testing, COMSEC monitoring, network operations and defense, personnel misconduct (PM), law enforcement (LE), and counterintelligence (CI) investigations. -At any time, the USG may inspect and seize data stored on this IS. -Communications using, or data stored on, this IS are not private, are subject to routine monitoring, interception, and search, and may be disclosed or used for any USG authorized purpose. -This IS includes security measures (e.g., authentication and access controls) to protect USG interests--not for your personal benefit or privacy. -Notwithstanding the above, using this IS does not constitute consent to PM, LE or CI investigative searching or monitoring of the content of privileged communications, or work product, related to personal representation or services by attorneys, psychotherapists, or clergy, and their assistants. Such communications and work product are private and confidential. See User Agreement for details.
Discussion
A logon banner can be used to inform users about the environment during the initial logon. In the DISA environment, logon banners are used to warn users against unauthorized entry and the possibility of legal action for unauthorized users, and advise all users that system use constitutes consent to monitoring. Failure to display a logon warning banner without this type of information could adversely impact the ability to prosecute unauthorized users and users who abuse the system. Satisfies: SRG-OS-000024-GPOS-00007, SRG-OS-000023-GPOS-00006
Fix
Preferably configure the /etc/otelnet/banner file and ensure the text specifies a logon banner in accordance with DISA requirements. Alternately the /etc/banner file may be used in accordance with DISA requirements below.STANDARD MANDATORY DOD NOTICE AND CONSENT BANNER You are accessing a U.S. Government (USG) Information System (IS) that is provided for USG-authorized use only. By using this IS (which includes any device attached to this IS), you consent to the following conditions: -The USG routinely intercepts and monitors communications on this IS for purposes including, but not limited to, penetration testing, COMSEC monitoring, network operations and defense, personnel misconduct (PM), law enforcement (LE), and counterintelligence (CI) investigations. -At any time, the USG may inspect and seize data stored on this IS. -Communications using, or data stored on, this IS are not private, are subject to routine monitoring, interception, and search, and may be disclosed or used for any USG authorized purpose. -This IS includes security measures (e.g., authentication and access controls) to protect USG interests--not for your personal benefit or privacy. -Notwithstanding the above, using this IS does not constitute consent to PM, LE or CI investigative searching or monitoring of the content of privileged communications, or work product, related to personal representation or services by attorneys, psychotherapists, or clergy, and their assistants. Such communications and work product are private and confidential. See User Agreement for details.
Rating Info
DISA Cat II. NIST impact 3.
Expert Comment
None
ACF2-OS-000030: IBM z/OS Inapplicable PPT entries must be invalidated.
Review program entries in the IBM Program Properties Table (PPT). You may use a third-party product to examine these entries however, to determine program entries issue the following command from an ISPF command line: TSO ISRDDN LOAD IEFSDPPT Press Enter. Interpret the display as follows: Examine contents at offset 8 Hex 'x2' - Bypass Password Protection Hex 'x3' - Bypass Password Protection Hex 'x4' - No data set Integrity Hex 'x5' - No data set Integrity Hex 'x6' - Both Hex 'x7' - Both Determine Privilege Key at offset 9. A value of hex '70' or less indicates an elevated privilege. For each module identified in the 'eyecatcher' that has BYPASS Password Protection, No data set Integrity, an elevated Privilege Key or any combination thereof, determine if there is a valid loaded module. Again, you may use a third-party product otherwise execute the following steps: From an ISPF command line: TSO ISRDDN LOAD <privileged module> Press Enter. If the return message is "Load Failed", make sure there is an entry in PARMLIB member SCHEDxx that revokes the excessive privilege, if this is not true, this is a finding.
Discussion
It is detrimental for operating systems to provide, or install by default, functionality exceeding requirements or mission objectives. These unnecessary capabilities or services are often overlooked and therefore may remain unsecured. They increase the risk to the platform by providing additional attack vectors. Operating systems are capable of providing a wide variety of functions and services. Some of the functions and services, provided by default, may not be necessary to support essential organizational operations (e.g., key missions, functions). Examples of non-essential capabilities include, but are not limited to, games, software packages, tools, and demonstration software, not related to requirements or providing a wide array of functionality not required for every mission, but which cannot be disabled.
Fix
Review the PPT and define all entries associated with non-existent or inapplicable modules as invalidated. Nullify the invalid IEFSDPPT entry by ensuring that there is a corresponding SCHED entry, which confers no special attributes. Use the following recommendations and techniques to provide protection for the PPT: Review the IEFSDPPT module and all programs that IBM has, by default, placed in the PPT to validate their applicability to the execution system. Refer to the IBM z/OS MVS Initialization and Tuning Reference documentation for the version and release of z/OS installed at the individual site for the actual contents of the default IEFSDPPT. Modules for products not in use on the system will have their special privileges explicitly revoked. Do this by placing a PPT entry for each module in the SYS1.PARMLIB(SCHEDxx) member, specifying no special privileges. The PPT entry for each overridden program will be in the following format, accepting the default (unprivileged) values for the sub parameters: PPT PGMNAME(<program name>) Assemble documentation regarding these PPT entries, and the ISSO will keep it on file. Include the following in the documentation: - The product and release for which the PPT entry was made - The last date this entry was reviewed to authenticate status - The reason the module's privileges are being revoked
Rating Info
DISA Cat II. NIST impact 3.
Expert Comment
None
ACF2-US-000010: IBM z/OS UNIX SUPERUSER resource must be protected in accordance with guidelines.
From the ISPF Command Shell enter: ACF RESOURCE(UNI) LIST LIKE(SUPER-) If the ACF2 rules for the SUPERUSER resource specify a default access of NONE, this is not a finding. If there are no ACF2 rules that allow access to the SUPERUSER resource, this is not a finding. If there is no ACF2 rule for CHOWN.UNRESTRICTED defined, this is not a finding. If the ACF2 rules for each of the SUPERUSER resources listed in the z/OS UNIX System Services Planning, Establishing UNIX Security, specify a default access of NONE, this is not a finding. If the ACF2 rules for each of the SUPERUSER resources listed in the UNIXPRIV CLASS RESOURCES Table in the z/OS UNIX System Services Planning, Establishing UNIX Security, restrict access to appropriate system tasks or systems programming personnel, this is not a finding.
Discussion
To mitigate the risk of unauthorized access to sensitive information by entities that have been issued certificates by DoD-approved PKIs, all DoD systems (e.g., web servers and web portals) must be properly configured to incorporate access control methods that do not rely solely on the possession of a certificate for access. Successful authentication must not automatically give an entity access to an asset or security boundary. Authorization procedures and controls must be implemented to ensure each authenticated entity also has a validated and current authorization. Authorization is the process of determining whether an entity, once authenticated, is permitted to access a specific asset. Information systems use access control policies and enforcement mechanisms to implement this requirement.
Fix
Configure ACF2 SUPERUSER resources for the UNIXPRIV resource class to restrict to appropriate system tasks and/or system programming personnel. Configure the ACF2 rules for the SUPERUSER resource to specify a default access of NONE. Configure no ACF2 rules that allow access to the SUPERUSER resource. Configure no ACF2 rule for CHOWN.UNRESTRICTED defined. Configure the ACF2 rules for each of the SUPERUSER resources listed in the UNIXPRIV CLASS RESOURCES Table in the z/OS UNIX System Services Planning, Establishing UNIX security to specify a default access of NONE. Configure the ACF2 rules for each of the SUPERUSER resources listed in the UNIXPRIV CLASS RESOURCES Table in the z/OS UNIX System Services Planning, Establishing UNIX security to restrict access to appropriate system tasks or systems programming personnel. Example: SET R(UNI) $KEY(SUPERUSER) TYPE(UNI) $MEMBER(SUPRUSER) FILESYS UID(sysprgmr LOG FILESYS.CHOWN UID(sysprgmr) LOG FILESYS.MOUNT UID(sysprog) LOG FILESYS.PFSCTL UID(sysprgmr) LOG FILESYS.VREGISTER UID(sysprgmr) LOG IPC.RMID UID(sysprgmr) LOG PROCESS.GETPSENT UID(sysprgmr) LOG PROCESS.KILL UID(sysprgmr) LOG PROCESS.PTRACE UID(sysprgmr) LOG SETPRIORITY UID(sysprgmr) LOG - UID(*) PREVENT
Rating Info
DISA Cat I. NIST impact 4.
Expert Comment
None
ACF2-JS-000060: IBM z/OS JES2 output devices must be properly controlled for Classified Systems.
If the Classification of the system is Unclassified, this is not applicable. Verify that the accesses for WRITER resources are restricted. If the following guidance is true, this is not a finding. The ACF2 resources and/or generic equivalent are defined with a default access of PREVENT. The ACF2 resources and/or generic equivalent identified below will be defined with access restricted to the operators and system programming personnel: JES2.LOCAL.devicename JES2.LOCAL.OFFn.* JES2.LOCAL.OFFn.JT JES2.LOCAL.OFFn.ST JES2.LOCAL.PRTn JES2.LOCAL.PUNn JES2.NJE.nodename JES2.RJE.devicename NOTE: Common sense should prevail during the analysis. For example, access to the offload output destinations should be limited to only systems personnel (e.g., operations staff/system programmers) on a classified system.
Discussion
To mitigate the risk of unauthorized access to sensitive information by entities that have been issued certificates by DoD-approved PKIs, all DoD systems (e.g., web servers and web portals) must be properly configured to incorporate access control methods that do not rely solely on the possession of a certificate for access. Successful authentication must not automatically give an entity access to an asset or security boundary. Authorization procedures and controls must be implemented to ensure each authenticated entity also has a validated and current authorization. Authorization is the process of determining whether an entity, once authenticated, is permitted to access a specific asset. Information systems use access control policies and enforcement mechanisms to implement this requirement. Access control policies include: identity-based policies, role-based policies, and attribute-based policies. Access enforcement mechanisms include: access control lists, access control matrices, and cryptography. These policies and mechanisms must be employed by the application to control access between users (or processes acting on behalf of users) and objects (e.g., devices, files, records, processes, programs, and domains) in the information system.
Fix
Configure the access authorization for resources defined to the WRITER resource class to be restricted to the operators and system programmers on a classified system only. Define resources in the ACP's respective WRITER class for each of the following output destinations: JES2.LOCAL.devicename JES2.LOCAL.OFFn.* JES2.LOCAL.OFFn.JT JES2.LOCAL.OFFn.ST JES2.LOCAL.PRTn JES2.LOCAL.PUNn JES2.NJE.nodename JES2.RJE.devicename The resource definition will be generic if all of the resources of the same type have identical access controls (e.g., if all off load transmitters are equivalent). If all users are permitted to route output to a specific destination, the resource controlling it may be defined with a default access of either NONE or READ. Otherwise it will be defined with a default access of NONE.
Rating Info
DISA Cat II. NIST impact 3.
Expert Comment
None
ACF2-OS-000260: IBM z/OS must not allow non-existent or inaccessible LINKLIST libraries.
From and ISPF Command line enter: TSO ISRDDN LINKLIST Review the list. If there are any DUMMY entries i.e., inaccessible LINKLINK libraries, this is a finding.
Discussion
Control of program execution is a mechanism used to prevent execution of unauthorized programs. Some operating systems may provide a capability that runs counter to the mission or provides users with functionality that exceeds mission requirements. This includes functions and services installed at the operating system level. Some of the programs, installed by default, may be harmful or may not be necessary to support essential organizational operations (e.g., key missions, functions). Removal of executable programs is not always possible; therefore, establishing a method of preventing program execution is critical to maintaining a secure system baseline. Methods for complying with this requirement include restricting execution of programs in certain environments, while preventing execution in other environments; or limiting execution of certain program functionality based on organization-defined criteria (e.g., privileges, subnets, sandboxed environments, or roles).
Fix
Review all entries contained in the LINKLIST for the actual existence of each library. Develop a plan of action to correct deficiencies. The Linklist is a default set of libraries that MVS searches for a specified program. This facility is used so that a user does not have to know the library names in which utility types of programs are stored. Control over membership in the Linklist is specified within the operating system. The data set SYS1.PARMLIB(LNKLSTxx) is used to specify the library names. (The xx is the suffix designated by the LNK parameter in the IEASYSxx member of SYS1.PARMLIB, or overridden by the computer operator at IPL.) Use the following recommendations and techniques to control the exposures created by the LINKLIST facility: -Avoid inclusion of sensitive libraries in the LNKLSTxx member unless absolutely required. -The LNKLSTxx and PROGxx (LNKLST entries) members will contain only required libraries. On a semiannual basis, Software Support should review the volume serial numbers, and should verify them in accordance with the system catalog. Software Support will remove all non-existent libraries. The ISSO should modify and/or delete the rules associated with these libraries.
Rating Info
DISA Cat II. NIST impact 3.
Expert Comment
None
ACF2-ES-000580: The CA-ACF2 GSO OPTS record value must be properly specified.
From the ACF Command enter: SET CONTROL(GSO) LIST OPTS If the GSO OPTS record values conform to the following requirements, this is not a finding. BLPLOG NOCMDREC CONSOLE(NOROLL) CPUTIME(LOCAL) DATE(MDY) NODDB DFTLID() DFTSTC() INFOLIST(none | AUDIT | SECURITY | SECURITY, AUDIT) JOBCK MAXVIO(10) NOTIFY RPTSCOPE SHRDASD STAMPSMF STC TAPEDSN TEMPDSN NOUADS NOVTAMOPEN
Discussion
Configuring the operating system to implement organization-wide security implementation guides and security checklists ensures compliance with federal standards and establishes a common security baseline across DoD that reflects the most restrictive security posture consistent with operational requirements.
Fix
Define the global options available to the system. BLPLOG NOCMDREC CONSOLE(NOROLL) CPUTIME(LOCAL) DATE(MDY) NODDB DFTLID() DFTSTC() INFOLIST(none | AUDIT | SECURITY | SECURITY, AUDIT) JOBCK MAXVIO(10) NOTIFY RPTSCOPE SHRDASD STAMPSMF STC TAPEDSN TEMPDSN NOUADS NOVTAMOPEN Example: SET C(GSO) INSERT OPTS BLPLOG NOCMDREC CONSOLE(NOROLL) CPUTIME(LOCAL) DATE(MDY) NODDB DFTLID() DFTSTC() INFOLIST(SECURITY, AUDIT) JOBCK MAXVIO(10) MODE(ABORT) NOTIFY RPTSCOPE SHRDASD STAMPSMF STC TAPEDSN TEMPDSN NOUADS NOVTAMOPEN F ACF2,REFRESH(OPTS)
Rating Info
DISA Cat II. NIST impact 3.
Expert Comment
None
ACF2-ES-000340: CA-ACF2 must limit access to data sets used to back up and/or dump SMF collection files to appropriate users and/or batch jobs that perform SMF dump processing.
Obtain the procedures and collection specifics for SMF data sets and backup. If the ESM data set rules for the SMF dump/backup files do not restrict WRITE or greater access to authorized site personnel (e.g., systems programmers and batch jobs that perform SMF processing), this is a finding. If the ESM dataset rules for the SMF dump/backup files do not restrict update access as documented in the site security plan, this is a finding. If the ESM data set rules for the SMF dump/backup files do not restrict READ access to auditors and others approved by the ISSM, this is a finding. If the ESM data set rules for the SMF dump/backup files do not specify that all (i.e., failures and successes) WRITE or greater access will be logged, this is a finding.
Discussion
To mitigate the risk of unauthorized access to sensitive information by entities that have been issued certificates by DoD-approved PKIs, all DoD systems (e.g., web servers and web portals) must be properly configured to incorporate access control methods that do not rely solely on the possession of a certificate for access. Successful authentication must not automatically give an entity access to an asset or security boundary. Authorization procedures and controls must be implemented to ensure each authenticated entity also has a validated and current authorization. Authorization is the process of determining whether an entity, once authenticated, is permitted to access a specific asset. Information systems use access control policies and enforcement mechanisms to implement this requirement. Access control policies include: identity-based policies, role-based policies, and attribute-based policies. Access enforcement mechanisms include: access control lists, access control matrices, and cryptography. These policies and mechanisms must be employed by the application to control access between users (or processes acting on behalf of users) and objects (e.g., devices, files, records, processes, programs, and domains) in the information system. Satisfies: SRG-OS-000080-GPOS-00048, SRG-OS-000206-GPOS-00084, SRG-OS-000324-GPOS-00125
Fix
Define WRITE or greater access to data sets used to back up and/or dump SMF collection files to be limited to system programmers and/or batch jobs that perform SMF dump processing. Ensure that all data set access is logged. Define data set rules for the SMF dump/backup files to restrict UPDATE access to others approved by the ISSM. Define READ Access to data sets used to back up and/or dumpSMF collection files to be limited to auditors and others approved by the ISSM. Ensure that all WRITE or greater access authority to SMF history files will be logged using the ESM's facilities. Review access authorization to critical system files. Evaluate the impact of correcting the deficiency. Develop a plan of action and implement the changes as required to protect data sets used to back up and/or dump SMF Collection Files. In z/OS systems, SMF data is the ultimate record of system activity. Therefore, SMF data is of the most sensitive and critical nature. While the length of time for which SMF data will be retained is not specifically regulated, it is imperative that the information is available for the longest possible time period in case of subsequent investigations. The statute of limitations varies according to the nature of a crime. It may vary by jurisdiction, and some crimes are not subject to a statute of limitations. Apply the following guidelines to the retention of SMF data for all DOD systems: (a) Retain at least two (2) copies of the SMF data. (b) Maintain SMF data for a minimum of one year. (c) All WRITE or greater access authority to SMF history files will be logged using the ACP's facilities. Only systems programming personnel and batch jobs that perform SMF functions will be authorized to update the SMF files.
Rating Info
DISA Cat II. NIST impact 3.
Expert Comment
None
ACF2-TS-000010: IBM z/OS TSOAUTH resources must be restricted to authorized users.
From the ISPF Command Shell enter: ACF SET RESOURCE(TSO) SET VERBOSE LIST LIKE(-) If the ACCT authorization is restricted to security personnel, this is not a finding. If the CONSOLE authorization is restricted to authorized systems personnel (e.g., systems programming personnel, operations staff, etc) and READ access may be given to all user when SDSF in install at the ISSOs discretion, this is not a finding. If the MOUNT authorization is restricted to DASD batch users only, this is not a finding. If the OPER authorization is restricted to authorized systems personnel (e.g., systems programming personnel, operations staff, etc), this is not a finding. If the PARMLIB authorization is restricted to only z/OS systems programming personnel and READ access may be given to auditors, this is not a finding. If the TESTAUTH authorization is restricted to only z/OS systems programming personnel, this is not a finding.
Discussion
To mitigate the risk of unauthorized access to sensitive information by entities that have been issued certificates by DoD-approved PKIs, all DoD systems (e.g., web servers and web portals) must be properly configured to incorporate access control methods that do not rely solely on the possession of a certificate for access. Successful authentication must not automatically give an entity access to an asset or security boundary. Authorization procedures and controls must be implemented to ensure each authenticated entity also has a validated and current authorization. Authorization is the process of determining whether an entity, once authenticated, is permitted to access a specific asset. Information systems use access control policies and enforcement mechanisms to implement this requirement. Access control policies include: identity-based policies, role-based policies, and attribute-based policies. Access enforcement mechanisms include: access control lists, access control matrices, and cryptography. These policies and mechanisms must be employed by the application to control access between users (or processes acting on behalf of users) and objects (e.g., devices, files, records, processes, programs, and domains) in the information system.
Fix
Configure the TSOAUTH resource class to control sensitive TSO/E commands. (Note: The resource type, resources, and/or resource prefixes identified below are examples of a possible installation. The actual resource type, resources, and/or resource prefixes are determined when the product is actually installed on a system through the product's installation guide and can be site specific.) Below is listed the access requirements for TSOAUTH resources. Ensure the guidelines for the resources and/or generic equivalent are followed. The ACCT authorization is restricted to security personnel. The CONSOLE authorization is restricted to authorized systems personnel (e.g., systems programming personnel, operations staff, etc) and READ access may be given to all user when SDSF in install at the ISSOs discretion. The MOUNT authorization is restricted to DASD batch users only. The OPER authorization is restricted to authorized systems personnel (e.g., systems programming personnel, operations staff, etc). The PARMLIB authorization is restricted to only z/OS systems programming personnel and READ access may be given to audit users. The TESTAUTH authorization is restricted to only z/OS systems programming personnel.
Rating Info
DISA Cat II. NIST impact 3.
Expert Comment
None
ACF2-US-000020: IBM z/OS UNIX security parameters in etc/profile must be properly specified.
From the ISPF COMMAND SHELL enter: ISHELL /etc/profile If the final or only instance of the UMASK command in /etc/profile is specified as "umask 077", this is not a finding. If the LOGNAME variable is marked read-only (i.e., "readonly LOGNAME") in /etc/profile, this is not a finding.
Discussion
Configuration settings are the set of parameters that can be changed in hardware, software, or firmware components of the system that affect the security posture and/or functionality of the system. Security-related parameters are those parameters impacting the security state of the system, including the parameters required to satisfy other security control requirements. Security-related parameters include, for example: registry settings; account, file, directory permission settings; and settings for functions, ports, protocols, services, and remote connections.
Fix
Configure the etc/profile to specify the UMASK command is executed with a value of 077 and the LOGNAME variable is marked read-only for the /etc/profile file, exceptions are documented with the ISSO.
Rating Info
DISA Cat II. NIST impact 3.
Expert Comment
None
ACF2-OS-000210: IBM z/OS must configure system waittimes to protect resource availability based on site priorities.
Refer to IEASYS00 member in SYS1.PARMLIB Concatenation. Determine proper SMFPRMxx member. Examine the JWT; SWT, and TWT values. If the JWT parameter is greater than "15" minutes, and the system is processing unclassified information, review the following items. If any of these items is true, this is not a finding. If a session is not terminated, but instead is locked out after 15 minutes of inactivity, a process must be in place that requires user identification and authentication before the session is unlocked. Session lock-out will be implemented through system controls or terminal screen protections. A system's default time for terminal lock-out or session termination may be lengthened to 30 minutes at the discretion of the ISSM or ISSO. The ISSA and/or ISSO will maintain the documentation for each system with a time-out adjusted beyond the 15-minute recommendation to explain the basis for this decision. The ISSM and/or ISSO may set selected userids to have a time-out of up to 60 minutes in order to complete critical reports or transactions without timing out. Each exception must meet the following criteria: The time-out exception cannot exceed 60 minutes. A letter of justification fully documenting the user requirement(s) must be submitted and approved by the site ISSM or ISSO. In addition, this letter must identify an alternate means of access control for the terminal(s) involved (e.g., a room that is locked at all times, a room with a cipher lock to limit access, a password protected screen saver set to 30 minutes or less, etc). The requirement must be revalidated on an annual basis. If the TWT and SWT values are equal or less than the JWT value, this is not a finding.
Discussion
Once an attacker establishes access to a system, the attacker often attempts to create a persistent method of reestablishing access. One way to accomplish this is for the attacker to enable an existing disabled account. Sending notification of account enabling actions to the System Administrator and ISSO is one method for mitigating this risk. Such a capability greatly reduces the risk that operating system accessibility will be negatively affected for extended periods of time and also provides logging that can be used for forensic purposes. In order to detect and respond to events that affect user accessibility and application processing, operating systems must audit account enabling actions and, as required, notify the appropriate individuals so they can investigate the event. To address access requirements, many operating systems can be integrated with enterprise-level authentication/access/auditing mechanisms that meet or exceed access control policy requirements.
Fix
Configure the SMFPRMxx JWT to "15" minutes for classified systems. The JWT parameter can be greater than 15 minutes if the system is processing unclassified information and the following items are reviewed. If a session is not terminated, but instead is locked out after 15 minutes of inactivity, a process must be in place that requires user identification and authentication before the session is unlocked. Session lock-out will be implemented through system controls or terminal screen protections. A system's default time for terminal lock-out or session termination may be lengthened to 30 minutes at the discretion of the ISSM or ISSO. The ISSM and/or ISSO will maintain the documentation for each system with a time-out adjusted beyond the 15-minute recommendation to explain the basis for this decision. The ISSM and/or ISSO may set selected userids to have a time-out of up to 60 minutes in order to complete critical reports or transactions without timing out. Each exception must meet the following criteria: The time-out exception cannot exceed 60 minutes. A letter of justification fully documenting the user requirement(s) must be submitted and approved by the site ISSM or ISSO. In addition, this letter must identify an alternate means of access control for the terminal(s) involved (e.g., a room that is locked at all times, a room with a cipher lock to limit access, a password protected screen saver set to 30 minutes or less, etc). The requirement must be revalidated on an annual basis. Configure any TWT and or SWT to be equal or less than the JWT.
Rating Info
DISA Cat II. NIST impact 3.
Expert Comment
None
ACF2-ES-000750: IBM z/OS UID(0) must be properly assigned.
From the ACF command screen enter: SET PROFILE(USER) DIVISION(OMVS) SET VERBOSE LIST LIKE(-) If UID(0) is assigned only to system tasks such as the z/OS/ UNIX kernel (i.e., OMVS), z/OS UNIX daemons (e.g., inetd, syslogd, ftpd), and other system software daemons, this is not a finding. If UID(0) is assigned to security administrators who create or maintain user account definitions; and to systems programming accounts dedicated to maintenance (e.g., SMP/E) of HFS-based components, this is not a finding. NOTE: The assignment of UID(0) confers full time superuser privileges. This is not appropriate for personal user accounts. Access to the BPX.SUPERUSER resource is used to allow personal user accounts to gain short-term access to superuser privileges. If UID(0) is assigned to non-systems or non-maintenance accounts, this is a finding.
Discussion
To assure accountability and prevent unauthenticated access, organizational users must be identified and authenticated to prevent potential misuse and compromise of the system. Organizational users include organizational employees or individuals the organization deems to have equivalent status of employees (e.g., contractors). Organizational users (and processes acting on behalf of users) must be uniquely identified and authenticated to all accesses, except for the following: 1) Accesses explicitly identified and documented by the organization. Organizations document specific user actions that can be performed on the information system without identification or authentication; and 2) Accesses that occur through authorized use of group authenticators without individual authentication. Organizations may require unique identification of individuals in group accounts (e.g., shared privilege accounts) or for detailed accountability of individual activity.
Fix
Assure that UID(0) is defined as specified below: UID(0) is assigned only to system tasks such as the z/OS UNIX kernel (i.e., OMVS), z/OS UNIX daemons (e.g., inetd, syslogd, ftpd), and other system software daemons. UID(0) is assigned to security administrators who create or maintain user account definitions; and to systems programming accounts dedicated to maintenance (e.g., SMP/E) of HFS-based components. NOTE: The assignment of UID(0) confers full time superuser privileges, this is not appropriate for personal user accounts. Access to the BPX.SUPERUSER resource is used to allow personal user accounts to gain short-term access to superuser privileges.
Rating Info
DISA Cat I. NIST impact 4.
Expert Comment
None
ACF2-OS-002330: IBM z/OS system administrator must develop a procedure to notify designated personnel if baseline configurations are changed in an unauthorized manner.
Ask the system administrator for the procedure to notify designated personnel if baseline configurations are changed in an unauthorized manner. If there is no procedure, this is a finding.
Discussion
Unauthorized changes to the baseline configuration could make the system vulnerable to various attacks or allow unauthorized access to the operating system. Changes to operating system configurations can have unintended side effects, some of which may be relevant to security. Detecting such changes and providing an automated response can help avoid unintended, negative consequences that could ultimately affect the security state of the operating system. The operating system's IMO/ISSO and SAs must be notified via email and/or monitoring system trap when there is an unauthorized modification of a configuration item.
Fix
Develop a procedure to notify designated personnel if baseline configurations are changed in an unauthorized manner.
Rating Info
DISA Cat II. NIST impact 3.
Expert Comment
None
ACF2-TC-000060: IBM z/OS Configuration files for the TCP/IP stack must be properly specified.
Refer to the procedure libraries defined to JES2 and locate the TCPIP JCL member. If the PROFILE and SYSTCPD DD statements specify the TCP/IP Profile and Data configuration files respectively, this not a finding. If the RESOLVER_CONFIG variable on the EXEC statement is set to the same file name specified on the SYSTCPD DD statement, this is not a finding. Note: If GLOBALTCPIPDATA is specified, any TCPIP.DATA statements contained in the specified file or data set take precedence over any TCPIP.DATA statements found using the appropriate environment's (native MVS or z/OS UNIX) search order. If GLOBALTCPIPDATA is not specified, the appropriate environment's (Native MVS or z/OS UNIX) search order is used to locate TCPIP.DATA.
Discussion
Configuring the operating system to implement organization-wide security implementation guides and security checklists ensures compliance with federal standards and establishes a common security baseline across DoD that reflects the most restrictive security posture consistent with operational requirements. Configuration settings are the set of parameters that can be changed in hardware, software, or firmware components of the system that affect the security posture and/or functionality of the system. Security-related parameters are those parameters impacting the security state of the system, including the parameters required to satisfy other security control requirements. Security-related parameters include, for example: registry settings; account, file, directory permission settings; and settings for functions, ports, protocols, services, and remote connections.
Fix
Review the TCP/IP started task JCL to ensure the configuration file names are specified on the appropriate DD statements and parameter option. During initialization the TCP/IP stack uses fixed search sequences to locate the PROFILE.TCPIP and TCPIP.DATA files. However, uncertainty is reduced and security auditing is enhanced by explicitly specifying the locations of the files. In the TCP/IP started task's JCL, Data Definition (DD) statements can be used to specify the locations of the files. The PROFILE DD statement identifies the PROFILE.TCPIP file and the SYSTCPD DD statement identifies the TCPIP.DATA file. The location of the TCPIP.DATA file can also be specified by coding the RESOLVER_CONFIG environment variable as a parameter of the ENVAR option in the TCP/IP started task's JCL. In fact, the value of this variable is checked before the SYSTCPD DD statement by some processes. However, not all processes (e.g., TN3270 Telnet Server) will access the variable to get the file location. Therefore specifying the file location explicitly, both on a DD statement and through the RESOLVER_CONFIG environment variable, reduces ambiguity. The systems programmer responsible for supporting ICS will ensure that the TCP/IP started task's JCL specifies the PROFILE and SYSTCPD DD statements for the PROFILE.TCPIP and TCPIP.DATA configuration files and TCP/IP started task's JCL includes the RESOLVER_CONFIG variable, set to the name of the file specified on the SYSTCPD DD statement. Note: If GLOBALTCPIPDATA is specified, any TCPIP.DATA statements contained in the specified file or data set take precedence over any TCPIP.DATA statements found using the appropriate environment's (native MVS or z/OS UNIX) search order. If GLOBALTCPIPDATA is not specified, the appropriate environment's (Native MVS or z/OS UNIX) search order is used to locate TCPIP.DATA.
Rating Info
DISA Cat II. NIST impact 3.
Expert Comment
None
ACF2-ES-000450: CA-ACF2 must be installed, functional, and properly configured.
Refer to the active tasks on the system. You can use IBM SDSF or the system Log. If CA-ACF2 is active, this is not a finding.
Discussion
Failure to provide logical access restrictions associated with changes to system configuration may have significant effects on the overall security of the system. When dealing with access restrictions pertaining to change control, it should be noted that any changes to the hardware, software, and/or firmware components of the operating system can have significant effects on the overall security of the system. Accordingly, only qualified and authorized individuals should be allowed to obtain access to operating system components for the purposes of initiating changes, including upgrades and modifications. Logical access restrictions include, for example, controls that restrict access to workflow automation, media libraries, abstract layers (e.g., changes implemented into third-party interfaces rather than directly into information systems), and change windows (e.g., changes occur only during specified times, making unauthorized changes easy to discover).
Fix
Assure that CA-ACF2 is active on the system.
Rating Info
DISA Cat I. NIST impact 4.
Expert Comment
None
ACF2-US-000030: IBM z/OS UNIX security parameters in /etc/rc must be properly specified.
From the ISPF COMMAND SHELL enter: ISHELL /etc/rc If all of the CHMOD commands in /etc/rc do not result in less restrictive access than what is specified in the tables below, this is not a finding. NOTE: The use of CHMOD commands in /etc/rc is required in most environments to comply with the required settings, especially for dynamic objects such as the /dev directory. The following represents a hierarchy for permission bits from least restrictive to most restrictive: 7 rwx (least restrictive) 6 rw- 3 -wx 2 -w- 5 r-x 4 r-- 1 --x 0 --- (most restrictive) If all of the CHAUDIT commands in /etc/rc do not result in less auditing than what is specified in the tables below this is not a finding. NOTE: The use of CHAUDIT commands in /etc/rc may not be necessary. If none are found, there is not a finding. The possible audit bits settings are as follows: f log for failed access attempts a log for failed and successful access - no auditing Directory Permission Bits User Audit Bits Function / [root] 755 faf Root level of all file systems. Holds critical mount points. /bin 1755 fff Shell scripts and executables for basic functions /dev 1755 fff Character-special files used when logging into the OMVS shell and during C language program compilation. Files are created during system IPL and on a per-demand basis. /etc 1755 faf Configuration programs and files (usually with locally customized data) used by z/OS UNIX and other product initialization processes /lib 1755 fff System libraries including dynamic link libraries and files for static linking /samples 1755 fff Sample configuration and other files /tmp 1777 fff Temporary data used by daemons, servers, and users. Note: /tmp must have the sticky bit on to restrict file renames and deletions. /u 1755 fff Mount point for user home directories and optionally for third-party software and other local site files /usr 1755 fff Shell scripts, executables, help (man) files and other data. Contains sub-directories (e.g., lpp) and mount points used by program products that may be in separate file systems. /var 1775 fff Dynamic data used internally by products and by elements and features of z/OS UNIX.
Discussion
Configuring the operating system to implement organization-wide security implementation guides and security checklists ensures compliance with federal standards and establishes a common security baseline across DoD that reflects the most restrictive security posture consistent with operational requirements.
Fix
Review the settings in the /etc/rc. The /etc/rcfile is the system initialization shell script. When z/OS UNIX kernel services start, /etc/rc is executed to set file permissions and ownership for dynamic system files and to perform other system startup functions such as starting daemons. There can be many commands in /etc/rc. There are two specific guidelines that must be followed: -Verify that the CHMOD or CHAUDIT command does not result in less restrictive security than what is specified in the table below. -Immediately prior to each command that starts a daemon, the _BPX_JOBNAME variable must be set to match the daemon's name (e.g., inetd, syslogd). The use of _BPX_USERID is at the site's discretion, but is recommended. Directory Permission Bits User Audit Bits Function / [root] 755 faf Root level of all file systems. Holds critical mount points. /bin 1755 fff Shell scripts and executables for basic functions /dev 1755 fff Character-special files used when logging into the OMVS shell and during C language program compilation. Files are created during system IPL and on a per-demand basis. /etc 1755 faf Configuration programs and files (usually with locally customized data) used by z/OS UNIX and other product initialization processes /lib 1755 fff System libraries including dynamic link libraries and files for static linking /samples 1755 fff Sample configuration and other files /tmp 1777 fff Temporary data used by daemons, servers, and users. Note: /tmp must have the sticky bit on to restrict file renames and deletions. /u 1755 fff Mount point for user home directories and optionally for third-party software and other local site files /usr 1755 fff Shell scripts, executables, help (man) files and other data. Contains sub-directories (e.g., lpp) and mount points used by program products that may be in separate file systems. /var 1775 fff Dynamic data used internally by products and by elements and features of z/OS UNIX.
Rating Info
DISA Cat II. NIST impact 3.
Expert Comment
None
ACF2-ES-000060: IBM z/OS system commands must be properly protected.
From a Command input line enter: SET RESOURCE(OPR) SET VERBOSE LIST LIKE(MVS-) NOTE: If CLASMAP defines OPERCMDS as anything other than the default of TYPE(OPR), replace OPR with the appropriate three letters. If the MVS resource is defined to the OPERCMDS class with a default access of PREVENT, and all access logged, i.e., MVS.** is defined with access of PREVENT, this is not finding. If Access to z/OS system commands defined in the table entitled MVS commands, RACF access authorities, and resource names, in the IBM z/OS MVS System Commands manual, is restricted to the appropriate personnel (e.g., operations staff, systems programming personnel, general users) as determined in the Documented site Security Plan, this is not a finding. Note: Display commands and others as deemed by the site IAW site security plan may be allowed for all users with no logging. The (MVS.SEND) Command will not be a finding if used by all.
Discussion
To mitigate the risk of unauthorized access to sensitive information by entities that have been issued certificates by DoD-approved PKIs, all DoD systems (e.g., web servers and web portals) must be properly configured to incorporate access control methods that do not rely solely on the possession of a certificate for access. Successful authentication must not automatically give an entity access to an asset or security boundary. Authorization procedures and controls must be implemented to ensure each authenticated entity also has a validated and current authorization. Authorization is the process of determining whether an entity, once authenticated, is permitted to access a specific asset. Information systems use access control policies and enforcement mechanisms to implement this requirement. Access control policies include: identity-based policies, role-based policies, and attribute-based policies. Access enforcement mechanisms include: access control lists, access control matrices, and cryptography. These policies and mechanisms must be employed by the application to control access between users (or processes acting on behalf of users) and objects (e.g., devices, files, records, processes, programs, and domains) in the information system.
Fix
Configure z/OS Sensitive System Commands to be defined to the OPERCMDS resource class. Only limited number of authorized people are able to issue these commands. All access is logged. Configure the MVS resource to be defined to the OPERCMDS class with a default access of PREVENT, all access is logged, and access is restricted to the appropriate personnel (e.g., operations staff, systems programming personnel, general users). Note: Ensure access to z/OS system commands defined in the MVS commands, RACF access authorities, and resource names, in the IBM z/OS MVS System Commands, is restricted to the appropriate personnel (e.g., operations staff, systems programming personnel, general users). Example for ACF2: $KEY(MVS) TYPE(OPR) ACTIVATE.- UID(sysprgmr) LOG ACTIVATE.- UID(*) PREVENT SET R(OPR) COMPILE 'ACF2.MVA.OPR(MVS)' STORE F ACF2,REBUILD(OPR)
Rating Info
DISA Cat II. NIST impact 3.
Expert Comment
None
ACF2-JS-000090: IBM z/OS Surrogate users must be controlled in accordance with proper security requirements.
Review the ACFGSO report executionuserid.SUBMIT resources. These are usually defined to CLASMAP as TYPE(SUR). NOTE: If CLASMAP defines SURROGAT as anything other than TYPE(SUR), replace SUR below with the appropriate three letters. If no executionuserid.SUBMIT resources are defined to the SURROGAT resource class, this is not applicable. If executionuserid.SUBMIT resources are defined to the SURROGAT resource class, review resource rules for TYPE(SUR). If the following items are in effect, this is not a finding. All executionlogonid.SUBMIT resources defined to the SURROGAT class specify a default access of PREVENT. All resource access is logged; at the discretion of the ISSM/ISSO, scheduling tasks may be exempted. Access authorization is restricted to scheduling tools, started tasks, or other system applications required for running production jobs. Other users may have minimal access required for running production jobs with documentation properly approved and filed with the site security official (ISSM or equivalent).
Discussion
To mitigate the risk of unauthorized access to sensitive information by entities that have been issued certificates by DoD-approved PKIs, all DoD systems (e.g., web servers and web portals) must be properly configured to incorporate access control methods that do not rely solely on the possession of a certificate for access. Successful authentication must not automatically give an entity access to an asset or security boundary. Authorization procedures and controls must be implemented to ensure each authenticated entity also has a validated and current authorization. Authorization is the process of determining whether an entity, once authenticated, is permitted to access a specific asset. Information systems use access control policies and enforcement mechanisms to implement this requirement. Access control policies include: identity-based policies, role-based policies, and attribute-based policies. Access enforcement mechanisms include: access control lists, access control matrices, and cryptography. These policies and mechanisms must be employed by the application to control access between users (or processes acting on behalf of users) and objects (e.g., devices, files, records, processes, programs, and domains) in the information system. Satisfies: SRG-OS-000080-GPOS-00048, SRG-OS-000326-GPOS-00126
Fix
All executionuserid.SUBMIT resources defined to the SURROGAT resource class specify a default of no access; all resource access is logged (at the discretion of the ISSM/ISSO scheduling tasks may be exempted) and access authorization is restricted to the minimum number of personnel required for running production jobs. Ensure the CLASMAP defines SURROGAT as TYPE(SUR). NOTE: If CLASMAP defines SURROGAT as anything other than TYPE(SUR), replace SUR below with the appropriate three letters. Ensure the following items are in effect: All executionlogonid.SUBMIT resources defined to the SURROGAT class specify a default access of PREVENT. All resource access is logged except for scheduling tasks. Access authorization is restricted to scheduling tools, started tasks, or other system applications required for running production jobs. Other users may have minimal access required for running production jobs with documentation properly approved and filed with the site security official (ISSM or equivalent). Consider the following recommendations when implementing security for Executionuserid.SUBMIT resources: Keep the use of Executionuserid.SUBMIT resources outside of those granted to the scheduling software to a minimum number of individuals. The simplest configuration is to only use Executionuserid.SUBMIT for the appropriate Scheduling task/software for production scheduling purposes as documented. Temporary Cross Authorization of the production batch ACID to the scheduling tasks may be allowed for a period for testing by the appropriate specific production Support Team members. Authorization, eligibility, and test period is determined by site policy. Access authorization is restricted to the minimum number of personnel required for running production jobs. However, Executionuserid.SUBMIT usage should not become the default for all jobs submitted by individual userids (i.e., system programmer must use their assigned individual userids for software installation, duties, whereas using a Executionuserid.SUBMIT resource would normally be for scheduled batch production only and as such must normally be limited to the scheduling task such as CONTROLM) and not granted as a normal daily basis to individual users. Example: $KEY(SRR) TYPE(SUR) SUBMIT UID(*******STC******CONTROLM) ALLOW - UID(*) PREVENT
Rating Info
DISA Cat II. NIST impact 3.
Expert Comment
None
ACF2-OS-000270: IBM z/OS must not allow non-existent or inaccessible Link Pack Area (LPA) libraries.
From and ISPF Command line enter: TSO ISRDDN LPA Review the list. If there are any DUMMY entries i.e., inaccessible LPA libraries, this is a finding.
Discussion
Control of program execution is a mechanism used to prevent execution of unauthorized programs. Some operating systems may provide a capability that runs counter to the mission or provides users with functionality that exceeds mission requirements. This includes functions and services installed at the operating system level. Some of the programs, installed by default, may be harmful or may not be necessary to support essential organizational operations (e.g., key missions, functions). Removal of executable programs is not always possible; therefore, establishing a method of preventing program execution is critical to maintaining a secure system baseline. Methods for complying with this requirement include restricting execution of programs in certain environments, while preventing execution in other environments; or limiting execution of certain program functionality based on organization-defined criteria (e.g., privileges, subnets, sandboxed environments, or roles).
Fix
Review all entries contained in the LPA members for the actual existence of each library. Develop a plan of action to correct deficiencies. The system Link Pack Area (LPA) is the component of MVS that maintains core operating system functions resident in main storage. A security concern exists when libraries from which LPA modules are obtained require APF authorization. Control over residence in the LPA is specified within the operating system in the following members of the data set SYS1.PARMLIB: - LPALSTxx specifies the names of libraries to be concatenated to SYS1.LPALIB when the LPA is generated at IPL in an MVS/XA or MVS/ESA system. (The xx is the suffix designated by the LPA parameter in the IEASYSxx member of SYS1.PARMLIB or overridden by the computer operator at system initial program load [IPL].) - IEAFIXxx specifies the names of modules from SYS1.SVCLIB, the LPALSTxx concatenation, and the LNKLSTxx concatenation that are to be temporarily fixed in central storage in the Fixed LPA (FLPA) for the duration of an IPL. (The xx is the suffix designated by the FIX parameter in the IEASYSxx member of SYS1.PARMLIB or overridden by the computer operator at IPL.) - IEALPAxx specifies the names of modules that will be loaded from the following: ? SYS1.SVCLIB ? The LPALSTxx concatenation ? The LNKLSTxx concatenation as a temporary extension to the existing Pageable LPA (PLPA) in the Modified LPA (MLPA) for the duration of an IPL. (The xx is the suffix designated by the MLPA parameter in the IEASYSxx member of SYS1.PARMLIB or overridden by the computer operator at IPL.) Use the following recommendations and techniques to control the exposures created by the LPA facility: -The LPALSTxx, IEAFIXxx, and IEALPAxx members will contain only required libraries. On a semiannual basis, Software Support should review the volume serial numbers, and should verify them in accordance with the system catalog. Software Support will remove all non-existent libraries. The ISSO should modify and/or delete the rules associated with these libraries.
Rating Info
DISA Cat II. NIST impact 3.
Expert Comment
None
ACF2-OS-002430: IBM z/OS system administrator must develop a procedure to shut down the information system, restart the information system, and/or notify the system administrator when anomalies in the operation of any security functions are discovered.
Ask the system administrator for the procedure to shut down the information system, restart the information system, and/or notify the system administrator when anomalies occur. If a procedure does not exist, this is a finding. If the procedure does not properly shut down the information system, restart the information system, and/or notify the system administrator when anomalies occur, this is a finding.
Discussion
If anomalies are not acted upon, security functions may fail to secure the system. Security function is defined as the hardware, software, and/or firmware of the information system responsible for enforcing the system security policy and supporting the isolation of code and data on which the protection is based. Security functionality includes, but is not limited to, establishing system accounts, configuring access authorizations (i.e., permissions, privileges), setting events to be audited, and setting intrusion detection parameters. Notifications provided by information systems include messages to local computer consoles, and/or hardware indications, such as lights. This capability must take into account operational requirements for availability for selecting an appropriate response. The organization may choose to shut down or restart the information system upon security function anomaly detection.
Fix
Develop a procedure to shut down the information system, restart the information system, and/or notify the system administrator when anomalies occur.
Rating Info
DISA Cat II. NIST impact 3.
Expert Comment
None
ACF2-IC-000030: IBM Integrated Crypto Service Facility (ICSF) STC data sets must be properly protected.
Verify that access to the IBM Integrated Crypto Service Facility (ICSF) STC data sets are properly restricted. The data sets to be protected are identified in the data set referenced in the CSFPARM DD statement of the ICSF started task(s) and/or batch job(s), the entries for CKDSN and PKDSN specify the data sets. If the ACF2 data set access authorizations does not restrict READ access to auditors this is a finding If the ACF2 data set access authorizations does not restrict WRITE and/or greater access to systems programming personnel this is a finding. If the ACF2 data set access authorizations does not restrict WRITE and/or greater access to the product STC(s) and/or batch job(s) this is a finding.
Discussion
IBM Integrated Crypto Service Facility (ICSF) STC data sets have the ability to use privileged functions and/or have access to sensitive data. Failure to properly restrict access to their data sets could result in violating the integrity of the base product which could result in compromising the operating system or sensitive data.
Fix
Ensure that WRITE and/or greater access to IBM Integrated Crypto Service Facility (ICSF) STC data sets are limited to system programmers and ICSF STC and/or batch jobs only. READ access can be given to auditors at the ISSOs discretion. The installing Systems Programmer will identify and document the product data sets and categorize them according to who will have what type of access and if required which type of access is logged. The installing systems programmer will identify any additional groups requiring access to specific data sets, and once documented the installing systems programmer will work with the ISSO to see that they are properly restricted to the ACP (Access Control Program) active on the system. (Note: The data sets and/or data set prefixes identified below are examples of a possible installation. The actual data sets and/or prefixes are determined when the product is actually installed on a system through the product's installation guide and can be site specific.) The data sets to be protected are identified in the data set referenced in the CSFPARM DD statement of the ICSF started task(s) and/or batch job(s), the entries for CKDSN and PKDSN specify the data sets. Note: Currently on most CSD systems the CKDSN specifies SYS3.CSF.CKDS and PKDSN specifies SYS3.CSF.PKDS. The following commands are provided as a sample for implementing data set controls: $KEY(SYS3) CSF.- UID(syspaudt) R(A) W(A) A(A) E(A) CSF.- UID(tstcaudt) R(A) W(A) A(A) E(A) CSF.- UID(icsfstc) R(A) W(A) A(A) E(A) CSF.- UID(audtaudt) R(A) E(A)
Rating Info
DISA Cat II. NIST impact 3.
Expert Comment
None
ACF2-ES-000910: ACF2 PSWD GSO record value must be set to prohibit password reuse for a minimum of five generations or more.
From an ACF command screen enter: SET CONTROL(GSO) LIST PSWD If "PSWDXHIST" is not specified, this is a finding. If "PSWDXHIST#" is set to "5" or greater, this is not a finding
Discussion
Password complexity, or strength, is a measure of the effectiveness of a password in resisting attempts at guessing and brute-force attacks. If the information system or application allows the user to consecutively reuse their password when that password has exceeded its defined lifetime, the end result is a password that is not changed as per policy requirements.
Fix
Configure Password option "PSWXHST" is coded and "PSWXHST#" is "5" or greater.
Rating Info
DISA Cat II. NIST impact 3.
Expert Comment
None
ACF2-ES-000230: IBM z/OS MCS consoles access authorization(s) for CONSOLE resource(s) must be properly protected.
Refer to the proper CONSOLxx member of SYS1.PARMLIB. From a ACF Command screen enter: ACF SET RESOURCE(CON) SET VERBOSE LIST LIKE(-) NOTE: If CLASMAP defines CONSOLE as anything other than the default of TYPE(CON), replace CON below with the appropriate three letters. If each console in the CONSOLxx member is defined to ACF2 with a corresponding resource rule for TYPE(CON), this is not a finding. If each TYPE(CON) rule is defined with PREVENT access by default, this is not a finding. If the logonid associated with each console has READ access to the corresponding resource defined in the CONSOLE resource class, this is not a finding. If access authorization for CONSOLE resources restricts READ access to operations and system programming personnel or authorized personnel, this is not a finding.
Discussion
To mitigate the risk of unauthorized access to sensitive information by entities that have been issued certificates by DoD-approved PKIs, all DoD systems (e.g., web servers and web portals) must be properly configured to incorporate access control methods that do not rely solely on the possession of a certificate for access. Successful authentication must not automatically give an entity access to an asset or security boundary. Authorization procedures and controls must be implemented to ensure each authenticated entity also has a validated and current authorization. Authorization is the process of determining whether an entity, once authenticated, is permitted to access a specific asset. Information systems use access control policies and enforcement mechanisms to implement this requirement. Access control policies include: identity-based policies, role-based policies, and attribute-based policies. Access enforcement mechanisms include: access control lists, access control matrices, and cryptography. These policies and mechanisms must be employed by the application to control access between users (or processes acting on behalf of users) and objects (e.g., devices, files, records, processes, programs, and domains) in the information system. Satisfies: SRG-OS-000080-GPOS-00048, SRG-OS-000324-GPOS-00125
Fix
Configuration should ensure that all MCS consoles are defined to the CONSOLE resource class and READ access is limited to operators and system programmers. Review the MCS console resources defined to z/OS and the ACP, and ensure they conform to those outlined below. Each console defined in the CONSOLxx parmlib members is defined to ACF2 with a corresponding resource rule for TYPE(CON). Each TYPE(CON) rule is defined with PREVENT access by default. The logonid associated with each console has READ access to the corresponding resource defined in the CONSOLE resource class. Access authorization for CONSOLE resources restricts READ access to operations and system programming personnel or authorized personnel. Example: $KEY(MZNC20) TYPE(CON) USERDATA(CONSOLE ID SECURITY) UID(sysprgmr) ALLOW UID(oper) ALLOW UID(MZNC20) ALLOW DATA(MZNC20 CONSOLE LOGONID ACCESS REQUIREMENTS) UID(*) PREVENT SET R(CON) COMPILE 'ACF2.MZN.CON(MZNC20)' STORE F ACF2,REBUILD(CON)
Rating Info
DISA Cat II. NIST impact 3.
Expert Comment
None
ACF2-OS-000250: Unsupported IBM z/OS system software must not be installed and/or active on the system.
This check applies to all products that meet the following criteria: - Uses authorized and restricted z/OS interfaces by utilizing Authorized Program Facility (APF) authorized modules or libraries. - Require access to system data sets or sensitive information or requires special or privileged authority to run. For the products in the above category, refer to the vendor's support lifecycle information for current versions and releases. If the software products currently running on the reviewed system are at a version greater than or equal to the products listed in the vendor's support lifecycle information, this is not a finding.
Discussion
Control of program execution is a mechanism used to prevent execution of unauthorized programs. Some operating systems may provide a capability that runs counter to the mission or provides users with functionality that exceeds mission requirements. This includes functions and services installed at the operating system level. Some of the programs, installed by default, may be harmful or may not be necessary to support essential organizational operations (e.g., key missions, functions). Removal of executable programs is not always possible; therefore, establishing a method of preventing program execution is critical to maintaining a secure system baseline. Methods for complying with this requirement include restricting execution of programs in certain environments, while preventing execution in other environments; or limiting execution of certain program functionality based on organization-defined criteria (e.g., privileges, subnets, sandboxed environments, or roles).
Fix
For all products that meet the following criteria: - Uses authorized and restricted z/OS interfaces by utilizing Authorized Program Facility (APF) authorized modules or libraries. - Require access to system data sets or sensitive information or requires special or privileged authority to run. The ISSO will ensure that unsupported system software for the products in the above category is removed or upgraded prior to a vendor dropping support. Authorized software which is NO longer supported is a CAT I vulnerability. The customer and site will be given six months to mitigate the risk, come up with a supported solution, or obtain a formal letter approving such risk/software.
Rating Info
DISA Cat I. NIST impact 4.
Expert Comment
None
ACF2-OS-000240: IBM z/OS Policy Agent must employ a deny-all, allow-by-exception firewall policy for allowing connections to other systems.
Examine the Policy Agent policy statements. If it can be determined that the policy agent employs a deny-all, allow-by exception firewall policy for allowing connections to other systems, this is not a finding.
Discussion
Failure to restrict network connectivity only to authorized systems permits inbound connections from malicious systems. It also permits outbound connections that may facilitate exfiltration of DoD data.
Fix
Develop a policy application and policy agent to employ a deny-all, allow-by-exception firewall policy for allowing connections to other systems.
Rating Info
DISA Cat II. NIST impact 3.
Expert Comment
None
ACF2-ES-000470: CA-ACF2 must limit Write and allocate access to the JES2 System data sets (e.g., Spool, Checkpoint, and Initialization parameters) to system programmers only.
The ACF2 data set rules for the JES2 System data sets (e.g., Spool, Checkpoint, and Initialization parameters) do not restrict WRITE and/or ALLOCATE access to only z/OS systems programming personnel. The ACF2 data set rules for the JES2 System data sets (e.g., Spool, Checkpoint, and Initialization parameters) allow inappropriate access not documented and approved by the ISSO. If both of the above are untrue, this is not a finding. If either of the above are true, this is a finding.
Discussion
To mitigate the risk of unauthorized access to sensitive information by entities that have been issued certificates by DoD-approved PKIs, all DoD systems (e.g., web servers and web portals) must be properly configured to incorporate access control methods that do not rely solely on the possession of a certificate for access. Successful authentication must not automatically give an entity access to an asset or security boundary. Authorization procedures and controls must be implemented to ensure each authenticated entity also has a validated and current authorization. Authorization is the process of determining whether an entity, once authenticated, is permitted to access a specific asset. Information systems use access control policies and enforcement mechanisms to implement this requirement. Satisfies: SRG-OS-000080-GPOS-00048, SRG-OS-000324-GPOS-00125, SRG-OS-000259-GPOS-00100
Fix
Review access authorization to critical system files. Evaluate the impact of correcting the deficiency. Develop a plan of action and implement the changes as required to protect System-level product installation libraries. Configure allocate access to all system-level product execution libraries to be limited to system programmers only. Access other than this should be documented and approved by the ISSO.
Rating Info
DISA Cat II. NIST impact 3.
Expert Comment
None
ACF2-JS-000080: IBM z/OS JES2 input sources must be controlled in accordance with the proper security requirements.
From the ACF input screen enter: SET CONTROL(GSO) LIST LIKE(CLASMAP-) Or SHOW CLASMAP {to determine the resource type for JESINPUT} NOTE: If CLASMAP defines JESINPUT as anything other than TYPE(INP), replace INP below with the appropriate three letters. SET RESOURCE(INP) LIST LIKE(-) NOTE: If any of the following are not defined within the JES2 parameters, the resource in the JESINPUT resource class does not have to be defined. Nodename is the NAME parameter in the NODE statement. Review the NJE node definitions by searching for NODE( in the JES2 parameters. OFFn, where n is the number of the offload receiver. Review the spool offload receiver definitions by searching for OFF( in the JES2 parameters. Rnnnn, where nnnn is the number of the remote workstation. Review the RJE node definitions by searching for RMT( in the JES2 parameters. RDRnn, where nn is the number of the reader. Review the reader definitions by searching for RDR( in the JES2 parameters. If the resources mentioned below are protected by generic and/or fully qualified rules defined to the JESINPUT resource class this is not a finding. If a default access of PREVENT is specified for all resources this is not a finding. If the ACF2 resources and/or generic equivalent identified below are defined with access restricted to the appropriate personnel this is not a finding. NOTE: Use common sense during the analysis. For example, access to the offload input sources should be limited to systems personnel (e.g., operations staff). NOTE: A default access of READ is allowed for input sources that are permitted to submit jobs for all users. No guidance on which input sources are appropriate for a default access of READ. However, common sense should prevail during the analysis. For example, a default access of READ would typically be inappropriate for RJE, NJE, offload, and STC input sources. INTRDR (internal reader for batch jobs) nodename (NJE node) OFFn.- (spool offload receiver) Rnnnn.- (RJE workstation) RDRnn (local card reader) STCINRDR (internal reader for started tasks) TSUINRDR (internal reader for TSO logons)
Discussion
To mitigate the risk of unauthorized access to sensitive information by entities that have been issued certificates by DoD-approved PKIs, all DoD systems (e.g., web servers and web portals) must be properly configured to incorporate access control methods that do not rely solely on the possession of a certificate for access. Successful authentication must not automatically give an entity access to an asset or security boundary. Authorization procedures and controls must be implemented to ensure each authenticated entity also has a validated and current authorization. Authorization is the process of determining whether an entity, once authenticated, is permitted to access a specific asset. Information systems use access control policies and enforcement mechanisms to implement this requirement. Access control policies include: identity-based policies, role-based policies, and attribute-based policies. Access enforcement mechanisms include: access control lists, access control matrices, and cryptography. These policies and mechanisms must be employed by the application to control access between users (or processes acting on behalf of users) and objects (e.g., devices, files, records, processes, programs, and domains) in the information system.
Fix
NOTE: If CLASMAP defines JESINPUT as anything other than TYPE(INP), replace INP below with the appropriate three letters. Configure resources in the JESINPUT resource class (i.e., TYPE(INP)) granting read access to authorized users for each of the following input resources: INTRDR (internal reader for batch jobs) nodename (NJE node) OFFn.- (spool offload receiver) OFFn.JR (spool offload job receiver) OFFn.SR (spool offload SYSOUT receiver) Rnnnn.RDm (RJE workstation) RDRnn (local card reader) STCINRDR (internal reader for started tasks) TSUINRDR (internal reader for TSO logons) The resource definition will be generic if all of the resources of the same type have identical access controls (e.g., if all off load receivers are equivalent). The default access will be NONE except for sources that are permitted to submit jobs for all users. Those resources may be defined as either NONE or READ. Nodename is the NAME parameter value specified on the NODE statement. Review the JES2 parameters for NJE node definitions by searching for NODE( in the JES2 parameters. OFFn, where n is the number of the offload receiver. Determine the numbers by searching for OFF( in the JES2 parameters. Rnnnn.RDm, where nnnn is the number of the remote workstation and m is the number of the reader. Determine the numbers by searching for .RD in the JES2 parameters. RDRnn, where nn is the number of the reader. Determine the numbers by searching for RDR( in the JES2 parameters. Ensure the following items are in effect: The CLASMAP record defines the JESINPUT resource class. Example: SHOW CLASMAP The resources mentioned in (b) are protected by generic and/or fully qualified rules defined to the JESINPUT resource class. A default access of PREVENT is specified for all resources. NOTE: A default access of READ is allowed for input sources that are permitted to submit jobs for all users. Currently, there is no guidance on which input sources are appropriate for a default access of READ. However, common sense should prevail during the analysis. For example, a default access of READ would typically be inappropriate for RJE, NJE, offload, and STC input sources. Examples: $KEY(STCINRDR) TYPE(INP) - UID(*) PREVENT $KEY(TSUINRDR) TYPE(INP) - UID(*) PREVENT $KEY(RDR*****) TYPE(INP) $MEMBER(RDR#####) - UID(*) PREVENT $KEY(OFF*****) TYPE(INP) $MEMBER(OFF#####) JR UID(oper) SERVICE(READ) JR UID(*) PREVENT SR UID(oper) SERVICE(READ) SR UID(*) PREVENT - UID(oper) SERVICE(READ) - UID(*) PREVENT
Rating Info
DISA Cat II. NIST impact 3.
Expert Comment
None
ACF2-ES-000380: CA-ACF2 must limit Update and Allocate access to system backup files to system programmers and/or batch jobs that perform DASD backups.
Collect from the storage management group the identification of the DASD backup files and all associated storage management userids/LIDs/ACIDs. If ESM data set rules for system DASD backup files do not restrict UPDATE and ALLOCATE access to z/OS systems programming and/or batch jobs that perform DASD backups, this is a finding. If READ Access to system backup data sets is not limited to auditors and others approved by the ISSM, this is a finding.
Discussion
Preventing non-privileged users from executing privileged functions mitigates the risk that unauthorized individuals or processes may gain unnecessary access to information or privileges. Privileged functions include, for example, establishing accounts, performing system integrity checks, or administering cryptographic key management activities. Non-privileged users are individuals that do not possess appropriate authorizations. Circumventing intrusion detection and prevention mechanisms or malicious code protection mechanisms are examples of privileged functions that require protection from non-privileged users.
Fix
Obtain the high level indexes to backup data sets names define their access to be restricted by the System's ESM to System Programmers and batch jobs that perform the backups. Define READ Access to system backup data sets to be limited to auditors and others approved by the ISSM.
Rating Info
DISA Cat II. NIST impact 3.
Expert Comment
None
ACF2-ES-000150: ACF2 Classes required to properly security the z/OS UNIX environment must be ACTIVE.
From the ISPF Command Shell enter: ACF SET CONTROL(GSO) SHOW CLASMAP If the CLASMAP DEFINITIONS list does not include entries for the FACILITY, SURROGAT, and UNIXPRIV resource classes, this is a finding. NOTE: TYPE CODES values should be unique for each resource. The default TYPE CODE values should be FAC, SUR, and UNI.
Discussion
To mitigate the risk of unauthorized access to sensitive information by entities that have been issued certificates by DoD-approved PKIs, all DoD systems (e.g., web servers and web portals) must be properly configured to incorporate access control methods that do not rely solely on the possession of a certificate for access. Successful authentication must not automatically give an entity access to an asset or security boundary. Authorization procedures and controls must be implemented to ensure each authenticated entity also has a validated and current authorization. Authorization is the process of determining whether an entity, once authenticated, is permitted to access a specific asset. Information systems use access control policies and enforcement mechanisms to implement this requirement. Access control policies include identity-based policies, role-based policies, and attribute-based policies. Access enforcement mechanisms include access control lists, access control matrices, and cryptography. These policies and mechanisms must be employed by the application to control access between users (or processes acting on behalf of users) and objects (e.g., devices, files, records, processes, programs, and domains) in the information system.
Fix
Define the CLASMAP DEFINITIONS to include entries for the FACILITY, SURROGAT, and UNIXPRIV resource classes. NOTE: TYPE CODES values should be unique for each resource. The default TYPE CODE values should be FAC, SUR, and UNI. Example: TSO ACF SHOW CLASMAP ACF SET CONTROL(GSO) INSERT CLASMAP.FACILITY RESOURCE(FACILITY) RSRCTYPE(FAC) ENTITYTLN (39)
Rating Info
DISA Cat II. NIST impact 3.
Expert Comment
None
ACF2-ES-000550: IBM z/OS LOGONID with the ACCTPRIV attribute must be restricted to the ISSO.
From the ACF Command screen enter: SET LID LIST IF(ACCTPRIV) If logonids with the ACCTPRIV attribute specified are not assigned to the security administrator, this is a finding.
Discussion
The use of security policy filters provides protection for the confidentiality of data by restricting the flow of data. A crucial part of any flow control solution is the ability to configure policy filters. This allows the operating system to enforce multiple and different security policies. Policy filters serve to enact and enforce the organizational policy as it pertains to controlling data flow.
Fix
Configure logonids with the ACCTPRIV attribute to be only reserved for use by the Security manager. The ACCTPRIV attribute cannot be scoped, and will be restricted exclusively to a site security administrator: Example: SET LID CHANGE logonid ACCTPRIV
Rating Info
DISA Cat II. NIST impact 3.
Expert Comment
None
ACF2-OS-000060: The IBM z/OS system administrator (SA) must develop a process notify appropriate personnel when accounts are deleted.
Develop a documented develop a process to notify appropriate personnel when accounts are deleted. If there is no documented process, this is a finding.
Discussion
When operating system accounts are disabled, user accessibility is affected. Accounts are utilized for identifying individual operating system users or for identifying the operating system processes themselves. Sending notification of account disabling events to the SA and information system security officer (ISSO) is one method for mitigating this risk. Such a capability greatly reduces the risk that operating system accessibility will be negatively affected for extended periods of time and also provides logging that can be used for forensic purposes. To address access requirements, many operating systems can be integrated with enterprise-level authentication/access/auditing mechanisms that meet or exceed access control policy requirements.
Fix
Develop a documented process to notify appropriate personnel when accounts are deleted.
Rating Info
DISA Cat II. NIST impact 3.
Expert Comment
None
ACF2-OS-000290: IBM z/OS LNKAUTH=APFTAB must be specified in the IEASYSxx member(s) in the currently active parmlib data set(s).
Refer to IEASYS00 member in SYS1.PARMLIB Concatenation. If LNKAUTH=APFTAB is not specified, this is a finding.
Discussion
Failure to specify LINKAUTH=APFTAB allows libraries other than those designated as APF to contain authorized modules which could bypass security and violate the integrity of the operating system environment. This expanded authorization list inhibits the ability to control inclusion of these modules.
Fix
Configure LNKAUTH=APFTAB in the IEASYS00 member of PARMLIB.
Rating Info
DISA Cat II. NIST impact 3.
Expert Comment
None
ACF2-OS-000330: IBM z/OS must use ICSF or SAF Key Rings for key management.
Any keys or Certificates must be managed in ICSF or the external security manager and not in UNIX files. From the ISPF Command Shell enter: OMVS enter find / -name *.kdb and find / -name *jks If any files are found, this is a finding.
Discussion
If the private key is discovered, an attacker can use the key to authenticate as an authorized user and gain access to the network infrastructure. The cornerstone of the PKI is the private key used to encrypt or digitally sign information. If the private key is stolen, this will lead to the compromise of the authentication and non-repudiation gained through PKI because the attacker can use the private key to digitally sign documents and pretend to be the authorized user. Both the holders of a digital certificate and the issuing authority must protect the computers, storage devices, or whatever they use to keep the private keys. Satisfies: SRG-OS-000067-GPOS-00035, SRG-OS-000068-GPOS-00036
Fix
Define all Keys/Certificates to ICSF or the security database. Remove any .kdb and .jks files.
Rating Info
DISA Cat II. NIST impact 3.
Expert Comment
None
ACF2-OS-000110: IBM z/OS SMF collection files (system MANx data sets or LOGSTREAM DASD) must have storage capacity to store at least one weeks worth of audit data.
Review the SMF dump procedure in the system. If the output data sets in the procedure have storage capacity to store at least one week's worth of audit data, this is not a finding.
Discussion
In order to ensure operating systems have a sufficient storage capacity in which to write the audit logs, operating systems need to be able to allocate audit record storage capacity. The task of allocating audit record storage capacity is usually performed during initial installation of the operating system.
Fix
Make sure output file and dump procedures allow storage capacity to store one week's worth of audit data.
Rating Info
DISA Cat II. NIST impact 3.
Expert Comment
None
ACF2-FT-000090: IBM z/OS FTP Server daemon must be defined with proper security parameters.
From the ISPF Command enter: ACF SET LID LIST LIKE(FTP-) SECTION(ALL) PROFILE(OMVS) NOTE: The JCL member is typically named FTPD. If all of the following are true, this is not a finding. If any of the following is untrue, this is a finding. The FTP daemon logonid is FTPD. The FTPD logonid is defined with the STC attribute. The FTPD logonid has the following z/OS UNIX attributes: UID(0), HOME directory '/', shell program /bin/sh.
Discussion
To assure accountability and prevent unauthenticated access, organizational users must be identified and authenticated to prevent potential misuse and compromise of the system. Organizational users include organizational employees or individuals the organization deems to have equivalent status of employees (e.g., contractors). Organizational users (and processes acting on behalf of users) must be uniquely identified and authenticated to all accesses, except for the following: 1) Accesses explicitly identified and documented by the organization. Organizations document specific user actions that can be performed on the information system without identification or authentication; and 2) Accesses that occur through authorized use of group authenticators without individual authentication. Organizations may require unique identification of individuals in group accounts (e.g., shared privilege accounts) or for detailed accountability of individual activity.
Fix
Define the FTP daemon to run under its own user account. Specifically, it does not share the account defined for the z/OS UNIX kernel. Define the FTP Server daemon account, privileges, and access authorizations to the ACP using the requirements below. The following commands can be used to create the user account that is required for the FTP daemon: SET LID INSERT FTPD NAME(FTPD) GROUP(STCTCPX) STC SET PROFILE(USER) DIVISION(OMVS) INSERT FTPD UID(0) HOME(/) PROGRAM(/bin/sh) F ACF2,REBUILD(USR),CLASS(P)
Rating Info
DISA Cat II. NIST impact 3.
Expert Comment
None
ACF2-ES-000630: ACF2 maintenance LOGONIDs must have corresponding GSO MAINT records.
From the ACF Command screen enter: SET LID LIST IF(MAINT) SET CONTROL(GSO) LIST LIKE(MAINT-) If every maintenance logonid has a corresponding GSO MAINT record, this is not a finding.
Discussion
Activity under unusual conditions can indicate hostile activity. For example, what is normal activity during business hours can indicate hostile activity if it occurs during off hours. Depending on mission needs and conditions, account usage restrictions based on conditions and circumstances may be critical to limit access to resources and data to comply with operational or mission access control requirements. Thus, the operating system must be configured to enforce the specific conditions or circumstances under which organization-defined accounts can be used (e.g., by restricting usage to certain days of the week, time of day, or specific durations of time).
Fix
Ensure that an associated GSO maintenance record exists for each special user logonid identifying the program(s) that it is permitted to access and the library where the program(s) resides. Define associated GSO MAINT record for each special user logonid, identifying the program(s) that it is permitted to access and the library where the program(s) resides. Every maintenance logonid has a corresponding GSO MAINT record. Example: SET C(GSO) INSERT MAINT.DFSMSHSM LIBRARY(SYS1.LINKLIB) LID(HSMDFDSS) PGM(ADRDSSU) F ACF2,REFRESH(MAINT)
Rating Info
DISA Cat II. NIST impact 3.
Expert Comment
None
ACF2-ES-000990: IBM z/OS must enforce a minimum eight character password length.
From an ACF command screen enter: SET CONTROL(GSO) LIST PSWD If "MINPSWD" is set to "8", this is not a finding.
Discussion
The shorter the password, the lower the number of possible combinations that need to be tested before the password is compromised. Password complexity, or strength, is a measure of the effectiveness of a password in resisting attempts at guessing and brute-force attacks. Password length is one factor of several that helps to determine strength and how long it takes to crack a password. Use of more characters in a password helps to exponentially increase the time and/or resources required to compromise the password.
Fix
Configure the Password option "MINPSWD" to "8".
Rating Info
DISA Cat II. NIST impact 3.
Expert Comment
None
ACF2-OS-000280: IBM z/OS must not have inaccessible APF libraries defined.
Refer to IEASYS00 member in SYS1.PARMLIB Concatenation. Determine proper APF and/or PROG member. Examine each entry and verify that it exists on the specified volume. If inaccessible APF libraries exist this is a finding. ISRDDN APF
Discussion
It is detrimental for operating systems to provide, or install by default, functionality exceeding requirements or mission objectives. These unnecessary capabilities or services are often overlooked and therefore may remain unsecured. They increase the risk to the platform by providing additional attack vectors. Operating systems are capable of providing a wide variety of functions and services. Some of the functions and services, provided by default, may not be necessary to support essential organizational operations (e.g., key missions, functions). Examples of non-essential capabilities include, but are not limited to, games, software packages, tools, and demonstration software, not related to requirements or providing a wide array of functionality not required for every mission, but which cannot be disabled.
Fix
Review the entire list of APF authorized libraries and remove those that are no longer valid designations.
Rating Info
DISA Cat II. NIST impact 3.
Expert Comment
None
ACF2-ES-000300: CA-ACF2 must limit Write and Allocate access to LINKLIST libraries to system programmers only.
From any ISPF input line, enter TSO ISRDDN LINKLIST If all of the following are untrue, this is not a finding. If any of the following is true, this is a finding. The ACP data set rules for LINKLIST libraries do not restrict WRITE and/or ALLOCATE access to only z/OS systems programming personnel. The ACP data set rules for LINKLIST libraries do not specify that all (i.e., failures and successes) WRITE and/or ALLOCATE access will be logged.
Discussion
To mitigate the risk of unauthorized access to sensitive information by entities that have been issued certificates by DoD-approved PKIs, all DoD systems (e.g., web servers and web portals) must be properly configured to incorporate access control methods that do not rely solely on the possession of a certificate for access. Successful authentication must not automatically give an entity access to an asset or security boundary. Authorization procedures and controls must be implemented to ensure each authenticated entity also has a validated and current authorization. Authorization is the process of determining whether an entity, once authenticated, is permitted to access a specific asset. Information systems use access control policies and enforcement mechanisms to implement this requirement. Access control policies include: identity-based policies, role-based policies, and attribute-based policies. Access enforcement mechanisms include: access control lists, access control matrices, and cryptography. These policies and mechanisms must be employed by the application to control access between users (or processes acting on behalf of users) and objects (e.g., devices, files, records, processes, programs, and domains) in the information system. Satisfies: SRG-OS-000080-GPOS-00048, SRG-OS-000259-GPOS-00100
Fix
Review access authorization to critical system files. Evaluate the impact of correcting the deficiency. Develop a plan of action and implement the changes as required to protect the LINKLIST libraries. Configure the update and allocate access to LINKLIST libraries to be limited to system programmers only and all update and allocate access is logged.
Rating Info
DISA Cat II. NIST impact 3.
Expert Comment
None
ACF2-ES-000560: IBM z/OS batch jobs with restricted ACF2 LOGONIDs must have the PGM(xxxxxxxx) and SUBAUTH attributes or the SOURCE(xxxxxxxx) attribute assigned to the corresponding LOGONIDs.
From the ACF command screen enter: SET LID SET VERBOSE LIST IF(RESTRICT) If the logonids that are associated with batch jobs have the RESTRICT attribute, then the logonids must also have the PGM(xxxxxxxx) and SUBAUTH attributes, or the SOURCE(xxxxxxxx) attribute specified. If all restricted logonids have the PGM(xxxxxxxx) and SUBAUTH attributes, and/or the SOURCE(xxxxxxxx) attribute, this is not a finding. If the PGM(xxxxxxxx) and SUBAUTH attributes or the SOURCE(xxxxxxxx) attribute is not specified for any restricted logonids, this is a finding.
Discussion
Activity under unusual conditions can indicate hostile activity. For example, what is normal activity during business hours can indicate hostile activity if it occurs during off hours. Depending on mission needs and conditions, account usage restrictions based on conditions and circumstances may be critical to limit access to resources and data to comply with operational or mission access control requirements. Thus, the operating system must be configured to enforce the specific conditions or circumstances under which organization-defined accounts can be used (e.g., by restricting usage to certain days of the week, time of day, or specific durations of time).
Fix
All batch jobs scheduled via an automation process will use the //*LOGONID xxxxxxxx card in the JCL stream to identify the userid. Use restricted logonids with the following parameter coded: RESTRICT One or both of the following will also be specified: PGM(xxxxxxxx) and SUBAUTH SOURCE(xxxxxxxx) The use of default IDs prevents the identification of tasks with individual users as mandated by policy, and prevents adequate accountability. Default IDs for batch processing will not be used. The use of USER= can also be used in the jobcard to identify the userid to be used for a job's processing.
Rating Info
DISA Cat II. NIST impact 3.
Expert Comment
None
ACF2-JS-000070: IBM z/OS JES2 output devices must be controlled in accordance with the proper security requirements.
From the ACF input screen enter: SET CONTROL(GSO) LIST LIKE(CLASMAP-) [To determine the resource class for WRITER] NOTE: If CLASMAP defines WRITER as anything other than TYPE(WTR), replace WTR below with the appropriate three letters. SET RESOURCE(WTR) LIST LIKE(-) If the JES2.- resource is defined to the WRITER resource class with a default access of PREVENT, this is not a finding. If the other resources mentioned below are protected by generic and/or fully qualified rules defined to the WRITER resource class with a default access of PREVENT, this is not a finding. If the ACF2 resources and/or generic equivalent identified below are defined with access restricted to the appropriate personnel, this is not a finding. NOTE: A default access of READ is allowed for output destinations that are permitted to route output for all users. Currently, there is no guidance on which output destinations are appropriate for a default access of READ. However, common sense should prevail during the analysis. For example, a default access of READ would typically be inappropriate for RJE, NJE, and offload output destinations. JES2 is typically the name of the JES2 subsystem. Refer to the SUBSYS report and locate the entry with the description of PRIMARY JOB ENTRY SUBSYSTEM. The SUBSYSTEM NAME of this entry is the name of the JES2 subsystem. OFFn, where n is the number of the offload transmitter. Determine the numbers by searching for OFF( in the JES2 parameters. PRTn, where n is the number of the local printer. Determine the numbers by searching for PRT( in the JES2 parameters. PUNn, where n is the number of the local card punch. Determine the numbers by searching for PUN( in the JES2 parameters. Nodename is the NAME parameter value specified on the NODE statement. Review the JES2 parameters for NJE node definitions by searching for NODE( in the report. Rnnnn.PRm, where nnnn is the number of the remote workstation and m is the number of the printer. Determine the numbers by searching for .PR in the JES2 parameters. Rnnnn.PUm, where nnnn is the number of the remote workstation and m is the number of the punch. Determine the numbers by searching for .PU in the JES2 parameters.
Discussion
To mitigate the risk of unauthorized access to sensitive information by entities that have been issued certificates by DoD-approved PKIs, all DoD systems (e.g., web servers and web portals) must be properly configured to incorporate access control methods that do not rely solely on the possession of a certificate for access. Successful authentication must not automatically give an entity access to an asset or security boundary. Authorization procedures and controls must be implemented to ensure each authenticated entity also has a validated and current authorization. Authorization is the process of determining whether an entity, once authenticated, is permitted to access a specific asset. Information systems use access control policies and enforcement mechanisms to implement this requirement. Access control policies include: identity-based policies, role-based policies, and attribute-based policies. Access enforcement mechanisms include: access control lists, access control matrices, and cryptography. These policies and mechanisms must be employed by the application to control access between users (or processes acting on behalf of users) and objects (e.g., devices, files, records, processes, programs, and domains) in the information system.
Fix
NOTE: If CLASMAP defines WRITER as anything other than TYPE(WTR), replace WTR below with the appropriate three letters. Configure the WRITER resource class (i.e., TYPE(WTR)) as follows with: JES2.- (backstop profile) JES2.LOCAL.OFFn.- (spool offload transmitter) JES2.LOCAL.OFFn.ST (spool offload SYSOUT transmitter) JES2.LOCAL.OFFn.JT (spool offload job transmitter) JES2.LOCAL.PRTn (local printer) JES2.LOCAL.PUNn (local punch) JES2.NJE.nodename (NJE node) JES2.RJE.Rnnnn.PRm (remote printer) JES2.RJE.Rnnnn.PUm (remote punch) Ensure the following items are in effect: The JES2.- resource is defined to the WRITER resource class with a default access of PREVENT. The other resources mentioned above are protected by generic and/or fully qualified rules defined to the WRITER resource class with a default access of PREVENT. NOTE: A default access of READ is allowed for output destinations that are permitted to route output for all users. Currently, there is no guidance on which output destinations are appropriate for a default access of READ. However, common sense should prevail during the analysis. For example, a default access of READ would typically be inappropriate for RJE, NJE, and offload output destinations. Examples: $KEY(JES2) TYPE(WTR) LOCAL.OFF- UID(*) PREVENT LOCAL.OFF-.JT UID(*) PREVENT LOCAL.OFF-.ST UID(oper) SERVICE(READ) ALLOW LOCAL.OFF-.ST UID(sysprgmr) SERVICE(READ) ALLOW LOCAL.OFF-.ST UID(seca) SERVICE(READ) ALLOW LOCAL.OFF-.ST UID(*) PREVENT LOCAL.PRT- UID(*) SERVICE(READ) ALLOW LOCAL.PUN- UID(*) PREVENT NJE.- UID(*) SERVICE(READ) ALLOW RJE.- UID(sysprgmr) SERVICE(READ) ALLOW RJE.- UID(*) PREVENT - UID(*) PREVENT
Rating Info
DISA Cat II. NIST impact 3.
Expert Comment
None
ACF2-FT-000120: IBM z/OS FTP.DATA configuration statements for the FTP Server must be specified in accordance with requirements.
Refer to the Data configuration file specified on the SYSFTPD DD statement in the FTP started task JCL. If the UMASK statement is coded with a value of "077", this is not a finding.
Discussion
This requirement is intended to cover both traditional interactive logons to information systems and general accesses to information systems that occur in other types of architectural configurations (e.g., service-oriented architectures).
Fix
Configure the FTP configuration to include the UMASK statement with a value of "077". If the FTP Server requires a UMASK value less restrictive than "077", requirements should be justified and documented with the ISSO.
Rating Info
DISA Cat II. NIST impact 3.
Expert Comment
None
ACF2-ES-000620: ACF2 REFRESH attribute must be restricted to security administrators' LOGON ID only.
From the ACF Command screen enter: SET LID LIST IF(REFRESH) If logonids exist with the REFRESH attribute not assigned to a site security administrator, this is a finding.
Discussion
Users with the refresh attribute have the ability to effect changes to ESM global system options. Unauthorized use could result in the compromise of the confidentiality, integrity, and availability of the operating system, ESM or customer data. Activity under unusual conditions can indicate hostile activity. For example, what is normal activity during business hours can indicate hostile activity if it occurs during off hours. Depending on mission needs and conditions, account usage restrictions based on conditions and circumstances may be critical to limit access to resources and data to comply with operational or mission access control requirements. Thus, the operating system must be configured to enforce the specific conditions or circumstances under which organization-defined accounts can be used (e.g., by restricting usage to certain days of the week, time of day, or specific durations of time).
Fix
Define any logonid with the REFRESH attribute to be assigned to a site security administrator only. Example: SET LID CHANGE logonid REFRESH
Rating Info
DISA Cat II. NIST impact 3.
Expert Comment
None
ACF2-ES-000090: CA-ACF2 must protect Memory and privileged program dumps in accordance with proper security requirements.
From a command input screen enter: SET RESOURCE (FAC) SET VERBOSE LIST LIKE (IEAABD-) NOTE: If CLASMAP defines FACILITY as anything other than the default of TYPE(FAC), replace FAC with the appropriate three letters. If the IEAABD. resource and/or generic equivalent is defined with PREVENT access and that access is not available to any user, this is not a finding. If the IEAABD.DMPAUTH. resource and/or generic equivalent is defined and access with SERVICE(READ) is limited to authorized users that have a valid job duties requirement for access, this is not a finding. If the IEAABD.DMPAUTH. resource and/or generic equivalent is defined and access with the SERVICE(UPDATE) or greater is restricted to only systems personnel and that all access is logged, this is not a finding. If the IEAABD.DMPAKEY. resource and/or generic equivalent is defined and all access is restricted to systems personnel and that all access is logged, this is not a finding.
Discussion
To mitigate the risk of unauthorized access to sensitive information by entities that have been issued certificates by DoD-approved PKIs, all DoD systems (e.g., web servers and web portals) must be properly configured to incorporate access control methods that do not rely solely on the possession of a certificate for access. Successful authentication must not automatically give an entity access to an asset or security boundary. Authorization procedures and controls must be implemented to ensure each authenticated entity also has a validated and current authorization. Authorization is the process of determining whether an entity, once authenticated, is permitted to access a specific asset. Information systems use access control policies and enforcement mechanisms to implement this requirement. Access control policies include: identity-based policies, role-based policies, and attribute-based policies. Access enforcement mechanisms include: access control lists, access control matrices, and cryptography. These policies and mechanisms must be employed by the application to control access between users (or processes acting on behalf of users) and objects (e.g., devices, files, records, processes, programs, and domains) in the information system.
Fix
Memory and privileged program dump resources are provided via resources in the FACILITY resource class. Ensure that the following are properly specified in the ACP. (Note: The resource type, resources, and/or resource prefixes identified below are examples of a possible installation. The actual resource type, resources, and/or resource prefixes are determined when the product is actually installed on a system through the product's installation guide and can be site specific.) Below is listed the access requirements for memory and privileged program dump resources. Ensure the guidelines for the resource type, resources, and/or generic equivalent are followed. When protecting the facilities for dumps lists via the FACILITY resource class, ensure that the following items are in effect: IEAABD. IEAABD.DMPAUTH. IEAABD.DMPAKEY. The ACF2 resources are defined with a default access of PREVENT. Ensure that no access is given to IEAABD. resource. Example: $KEY(IEAABD) TYPE(FAC) - UID(*) PREVENT IEAABD.DMPAUTH. READ access is limited to authorized users that have a valid job duties requirement for access. UPDATE access will be restricted to system programming personnel and access will be logged. Example: $KEY(IEAABD) TYPE(FAC) DMPAUTH.- UID(sysprgmr) SERVICE(UPDATE) LOG DMPAUTH.- UID(authusers) SERVICE(READ) DMPAUTH.- UID(*) PREVENT IEAABD.DMPAKEY. access will be restricted to system programming personnel and access will be logged. Example: $KEY(IEAABD) TYPE(FAC) DMPAKEY.- UID(sysprgmr) LOG DMPAKEY.- UID(*) PREVENT
Rating Info
DISA Cat II. NIST impact 3.
Expert Comment
None
ACF2-TC-000040: IBM z/OS permission bits and user audit bits for HFS objects that are part of the Base TCP/IP component must be configured properly.
From the ISPF Command shell enter: omvs At the input line enter: cd /etc enter ls -alW If the following File permission and user Audit Bits are true, this is not a finding. /etc/hosts 0744 faf /etc/protocol 0744 faf /etc/resolv.conf 0744 faf /etc/services 0740 faf cd /usr ls -alW If the following file permission and user Audit Bits are true, this is not a finding. /usr/lpp/tcpip/sbin 0755 faf /usr/lpp/tcpip/bin 0755 faf Notes: Some of the files listed above are not used in every configuration. The absence of a file is not considered a finding. The following represents a hierarchy for permission bits from least restrictive to most restrictive: 7 rwx (least restrictive) 6 rw- 3 -wx 2 -w- 5 r-x 4 r-- 1 --x 0 --- (most restrictive) The possible audit bits settings are as follows: f log for failed access attempts a log for failed and successful access - no auditing
Discussion
To mitigate the risk of unauthorized access to sensitive information by entities that have been issued certificates by DoD-approved PKIs, all DoD systems (e.g., web servers and web portals) must be properly configured to incorporate access control methods that do not rely solely on the possession of a certificate for access. Successful authentication must not automatically give an entity access to an asset or security boundary. Authorization procedures and controls must be implemented to ensure each authenticated entity also has a validated and current authorization. Authorization is the process of determining whether an entity, once authenticated, is permitted to access a specific asset. Information systems use access control policies and enforcement mechanisms to implement this requirement. Access control policies include: identity-based policies, role-based policies, and attribute-based policies. Access enforcement mechanisms include: access control lists, access control matrices, and cryptography. These policies and mechanisms must be employed by the application to control access between users (or processes acting on behalf of users) and objects (e.g., devices, files, records, processes, programs, and domains) in the information system.
Fix
With the assistance of a systems programmer with UID(0) and/or SUPERUSER access, configure the UNIX permission bits and user audit bits on the HFS directories and files for the FTP Server to conform to the specifications in the table below: BASE TCP/IP HFS Object Security Settings File Permission Bits User Audit Bits /etc/hosts 0744 faf /etc/protocol 0744 faf /etc/resolv.conf 0744 faf /etc/services 0740 faf /usr/lpp/tcpip/sbin 0755 faf /usr/lpp/tcpip/bin 0755 faf Some of the files listed above (e.g., /etc/resolv.conf) are not used in every configuration. While the absence of a file is generally not a security issue, the existence of a file that has not been properly secured can often be an issue. Therefore, all directories and files that do exist will have the specified permission and audit bit settings. The following represents a hierarchy for permission bits from least restrictive to most restrictive: 7 rwx (least restrictive) 6 rw- 3 -wx 2 -w- 5 r-x 4 r-- 1 --x 0 --- (most restrictive) The possible audit bits settings are as follows: f log for failed access attempts a log for failed and successful access - no auditing The following commands can be used (from a user account with an effective UID(0)) to update the permission bits and audit bits: chmod 0744 /etc/hosts chaudit w=sf,rx+f /etc/hosts chmod 0744 /etc/protocol chaudit w=sf,rx+f /etc/protocol chmod 0744 /etc/resolv.conf chaudit w=sf,rx+f /etc/resolv.conf chmod 0740 /etc/services chaudit w=sf,rx+f /etc/services chmod 0755 /usr/lpp/tcpip/bin chaudit w=sf,rx+f /usr/lpp/tcpip/bin chmod 0755 /usr/lpp/tcpip/sbin chaudit w=sf,rx+f /usr/lpp/tcpip/sbin
Rating Info
DISA Cat II. NIST impact 3.
Expert Comment
None
ACF2-US-000060: IBM z/OS BPX resource(s) must be protected in accordance with security requirements.
From the ISPF Command Shell enter: ACF SET RESOURCE(FAC) SET VERBOSE LIST LIKE(BPX-) If the ACF2 rules for the BPX resource specify a default access of NONE, this is not a finding. If there are no ACF2 rules that allow access to the BPX resource, this is not a finding. If there is no ACF2 rule for BPX.SAFFASTPATH defined, this is not a finding. If the ACF2 rules for each of the BPX resources listed in z/OS UNIX System Services Planning, Establishing UNIX security, specify a default access of NONE, this is not a finding. If the ACF2 rules for each of the BPX resources listed in the in z/OS UNIX System Services Planning, Establishing UNIX security, restrict access to appropriate system tasks or systems programming personnel, this is not a finding.
Discussion
To mitigate the risk of unauthorized access to sensitive information by entities that have been issued certificates by DoD-approved PKIs, all DoD systems (e.g., web servers and web portals) must be properly configured to incorporate access control methods that do not rely solely on the possession of a certificate for access. Successful authentication must not automatically give an entity access to an asset or security boundary. Authorization procedures and controls must be implemented to ensure each authenticated entity also has a validated and current authorization. Authorization is the process of determining whether an entity, once authenticated, is permitted to access a specific asset. Information systems use access control policies and enforcement mechanisms to implement this requirement. Access control policies include: identity-based policies, role-based policies, and attribute-based policies. Access enforcement mechanisms include: access control lists, access control matrices, and cryptography. These policies and mechanisms must be employed by the application to control access between users (or processes acting on behalf of users) and objects (e.g., devices, files, records, processes, programs, and domains) in the information system.
Fix
Configure BPX. Resources to be properly protected and access is restricted to appropriate system tasks or systems programming personnel. Configure the following items for the FACILITY resource class, TYPE(FAC): The ACF2 rules for the BPX resource specify a default access of NONE. Example: $KEY(BPX) TYPE(FAC) - UID(*) PREVENT There are no ACF2 rules that allow access to the BPX resource. Example: $KEY(BPX) TYPE(FAC) - UID(*) PREVENT There is no ACF2 rule for BPX.SAFFASTPATH defined. Example: $KEY(BPX) TYPE(FAC) SAFFASTPATH UID(*) PREVENT The ACF2 rules for each of the BPX resources listed in the General Facility Class BPX Resources Table, in the z/OS UNIX System Services Planning, Establishing UNIX security, specify a default access of NONE. Example: $KEY(BPX) TYPE(FAC) DAEMON UID(*) PREVENT DEBUG UID(*) PREVENT FILEATTR.APF UID(*) PREVENT FILEATTR.PROGCTL UID(*) PREVENT JOBNAME UID(*) PREVENT SAFFASTPATH UID(*) PREVENT SERVER UID(*) PREVENT SMF UID(*) PREVENT STOR.SWAP UID(*) PREVENT SUPERUSER UID(*) PREVENT WLMSERVER UID(*) PREVENT The ACF2 rules for each of the BPX resources listed in the General Facility Class BPX Resources Table, in the z/OS UNIX System Services Planning, Establishing UNIX security, restrict access to appropriate system tasks or systems programming personnel as specified. Example: $KEY(BPX) TYPE(FAC) DAEMON UID(*******STC******FTPD) SERVICE(READ) LOG DAEMON UID(*******STC******INETD) SERVICE(READ) LOG DAEMON UID(*******STC******NAMED) SERVICE(READ) LOG DAEMON UID(*******STC******OMVSKERN) SERVICE(READ) LOG DAEMON UID(*******STC******OMVS) SERVICE(READ) LOG DAEMON UID(*******STC******OROUTED) SERVICE(READ) LOG DAEMON UID(*******STC******OSNMPD) SERVICE(READ) LOG
Rating Info
DISA Cat II. NIST impact 3.
Expert Comment
None
ACF2-ES-000930: ACF2 TSOCRT GSO record values must be set to obliterate the logon to ASCII CRT devices.
From the ISPF Command Shell enter: ACF SET CONTROL(GSO) <enter> LIST TSOCRT If the GSO TSOCRT record values conform to the following requirements, this is not a finding. STRING(A12FA11C1A270C0D)
Discussion
To prevent the compromise of authentication information, such as passwords during the authentication process, the feedback from the operating system must not provide any information allowing an unauthorized user to compromise the authentication mechanism. Obfuscation of user-provided information that is typed into the system is a method used when addressing this risk. Displaying asterisks when a user types in a password is an example of obscuring feedback of authentication information.
Fix
Define a clear string used to obliterate the logon to ASCII CRT devices. STRING(A12FA11C1A270C0D) Example: SET C(GSO) INSERT TSOCRT STRING(A12FA11C1A270C0D) F ACF2,REFRESH(TSOCRT)
Rating Info
DISA Cat II. NIST impact 3.
Expert Comment
None
ACF2-OS-002380: IBM z/OS system administrator must develop a procedure to automatically remove or disable emergency accounts after the crisis is resolved or 72 hours.
Ask the system administrator for the procedure to automatically remove or disable emergency accounts after the crisis is resolved or 72 hours. If there is no procedure, this is a finding.
Discussion
Emergency accounts are privileged accounts that are established in response to crisis situations where the need for rapid account activation is required. Therefore, emergency account activation may bypass normal account authorization processes. If these accounts are automatically disabled, system maintenance during emergencies may not be possible, thus adversely affecting system availability. Emergency accounts are different from infrequently used accounts (i.e., local logon accounts used by the organization's system administrators when network or normal logon/access is not available). Infrequently used accounts are not subject to automatic termination dates. Emergency accounts are accounts created in response to crisis situations, usually for use by maintenance personnel. The automatic expiration or disabling time period may be extended as needed until the crisis is resolved; however, it must not be extended indefinitely. A permanent account should be established for privileged users who need long-term maintenance accounts. To address access requirements, many operating systems can be integrated with enterprise-level authentication/access mechanisms that meet or exceed access control policy requirements.
Fix
Develop a procedure to remove or disable emergency user accounts after the crisis is resolved or 72 hours.
Rating Info
DISA Cat II. NIST impact 3.
Expert Comment
None
ACF2-SM-000030: IBM z/OS DFSMS control data sets must be protected in accordance with security requirements.
Review the logical parmlib data sets, example: SYS1.PARMLIB(IGDSMSxx), to identify the fully qualified file names for the following SMS data sets: Source Control Data Set (SCDS) Active Control Data Set (ACDS) Communications Data Set (COMMDS) Automatic Class Selection Routine Source Data Sets (ACS) ACDS Backup COMMDS Backup If the ACF2 data set rules for the SCDS, ACDS, COMMDS, and ACS data sets restrict UPDATE and ALLOCATE access to only systems programming personnel, this not is a finding. If the ACF2 data set rules for the SCDS, ACDS, COMMDS, and ACS data sets do not restrict UPDATE and ALLOCATE access to only systems programming personnel, this is a finding. Note: At the discretion of the ISSM, DASD administrators are allowed UPDATE access to the control data sets.
Discussion
To mitigate the risk of unauthorized access to sensitive information by entities that have been issued certificates by DoD-approved PKIs, all DoD systems (e.g., web servers and web portals) must be properly configured to incorporate access control methods that do not rely solely on the possession of a certificate for access. Successful authentication must not automatically give an entity access to an asset or security boundary. Authorization procedures and controls must be implemented to ensure each authenticated entity also has a validated and current authorization. Authorization is the process of determining whether an entity, once authenticated, is permitted to access a specific asset. Information systems use access control policies and enforcement mechanisms to implement this requirement. Access control policies include: identity-based policies, role-based policies, and attribute-based policies. Access enforcement mechanisms include: access control lists, access control matrices, and cryptography. These policies and mechanisms must be employed by the application to control access between users (or processes acting on behalf of users) and objects (e.g., devices, files, records, processes, programs, and domains) in the information system.
Fix
Configure DFSMS control data sets to restrict UPDATE or ALLOCATE access to system programmers responsible for DASD management. Justification is required for any additional access. Review the SYS1.PARMLIB(IGDSMSxx) data set to identify the fully qualified file names for the following SMS data sets: Source Control Data Set (SCDS) Active Control Data Set (ACDS) Communications Data Set (COMMDS) Automatic Class Selection Routine Source Data Sets (ACS) ACDS Backup COMMDS Backup Define ACF2 data set rules for the SCDS, ACDS, COMMDS, and ACS data sets to restrict UPDATE and ALLOCATE access to only systems programming personnel. Note: At the discretion of the ISSM, DASD administrators are allowed UPDATE access to the control data sets. Example: $KEY(S3D) $PREFIX(SYS3) DFSMS.MVA.ACDS UID(uuuuuuuu) R(A) W(L) A(L) E(A)
Rating Info
DISA Cat II. NIST impact 3.
Expert Comment
None
ACF2-OS-000070: IBM z/OS system administrator must develop a process notify appropriate personnel when accounts are created.
Ask the system Administrator for the documented process to notify appropriate personnel when accounts are created. If there is no documented process, this is a finding.
Discussion
Once an attacker establishes access to a system, the attacker often attempts to create a persistent method of reestablishing access. One way to accomplish this is for the attacker to create a new account. Notification of account creation is one method for mitigating this risk. A comprehensive account management process will ensure an audit trail which documents the creation of operating system user accounts and notifies administrators and ISSOs that it exists. Such a process greatly reduces the risk that accounts will be surreptitiously created and provides logging that can be used for forensic purposes. To address access requirements, many operating systems can be integrated with enterprise-level authentication/access/auditing mechanisms that meet or exceed access control policy requirements.
Fix
Develop a documented process to notify appropriate personnel when accounts are created.
Rating Info
DISA Cat II. NIST impact 3.
Expert Comment
None
ACF2-SL-000010: IBM z/OS permission bits and user audit bits for HFS objects that are part of the Syslog daemon component must be configured properly.
From an ISPF enter: cd /usr/sbin Enter ls -alW If File Permission Bits and User Audit Bits for SYSLOG Daemon HFS directories and files is as below, this is not a finding. /usr/sbin/syslogd 1740 fff Enter: cd /etc/ Enter ls -alW If the file Permission Bits and User Audit Bits for Output log file defined in the configuration file are as below, this is not a finding. /etc/syslog.conf 0744 faf 0744 fff Notes: The /usr/sbin/syslogd object is a symbolic link to /usr/lpp/tcpip/sbin/syslogd. The permission and user audit bits on the target of the symbolic link must have the required settings. The /etc/syslog.conf file may not be the configuration file the daemon uses. It is necessary to check the script or JCL used to start the daemon to determine the actual configuration file. For example, in /etc/rc: _BPX_JOBNAME='SYSLOGD' /usr/sbin/syslogd -f /etc/syslog.conf For example, in the SYSLOGD started task JCL: //SYSLOGD EXEC PGM=SYSLOGD,REGION=30M,TIME=NOLIMIT //PARM='POSIX(ON) ALL31(ON)/ -f /etc/syslogd.conf' //SYSLOGD EXEC PGM=SYSLOGD,REGION=30M,TIME=NOLIMIT //PARM='POSIX(ON) ALL31(ON) /-f //''SYS1.TCPPARMS(SYSLOG)''' The following represents a hierarchy for permission bits from least restrictive to most restrictive: 7 rwx (least restrictive) 6 rw- 3 -wx 2 -w- 5 r-x 4 r-- 1 --x 0 --- (most restrictive) The possible audit bits settings are as follows: f log for failed access attempts a log for failed and successful access - no auditing
Discussion
HFS directories and files of the Syslog daemon provide the configuration and executable properties of this product. Failure to properly secure these objects could lead to unauthorized access. This exposure may result in the compromise of the integrity and availability of the operating system environment, ACP, and customer data.
Fix
With the assistance of a systems programmer with UID(0) and/or SUPERUSER access, review the UNIX permission bits and user audit bits on the HFS directories and files for the Syslog daemon. Ensure they conform to the specifications in the SYSLOG Daemon HFS Object Security Settings table below. Log files should have security that prevents anyone except the syslogd process and authorized maintenance jobs from writing to or deleting them. A maintenance process to periodically clear the log files is essential. Logging stops if the target file system becomes full. SYSLOG Daemon HFS Object Security Settings File Permission Bits User Audit Bits /usr/sbin/syslogd 1740 fff [Configuration File] /etc/syslog.conf 0744 faf [Output log file defined in the configuration file] 0744 fff The following represents a hierarchy for permission bits from least restrictive to most restrictive: 7 rwx (least restrictive) 6 rw- 3 -wx 2 -w- 5 r-x 4 r-- 1 --x 0 --- (most restrictive) The possible audit bits settings are as follows: f log for failed access attempts a log for failed and successful access - no auditing NOTES: The /usr/sbin/syslogd object is a symbolic link to /usr/lpp/tcpip/sbin/syslogd. The permission and user audit bits on the target of the symbolic link must have the required settings. The /etc/syslog.conf file may not be the configuration file the daemon uses. It is necessary to check the script or JCL used to start the daemon to determine the actual configuration file. For example, in /etc/rc: _BPX_JOBNAME='SYSLOGD' /usr/sbin/syslogd -f /etc/syslog.conf For example, in the SYSLOGD started task JCL: //SYSLOGD EXEC PGM=SYSLOGD,REGION=30M,TIME=NOLIMIT //PARM='POSIX(ON) ALL31(ON)/ -f /etc/syslogd.conf' //SYSLOGD EXEC PGM=SYSLOGD,REGION=30M,TIME=NOLIMIT //PARM='POSIX(ON) ALL31(ON) /-f //''SYS1.TCPPARMS(SYSLOG)''' The following commands can be used (from a user account with an effective UID(0)) to update the permission bits and audit bits: chmod 1740 /usr/lpp/tcpip/sbin/syslogd chaudit rwx=f /usr/lpp/tcpip/sbin/syslogd chmod 0744 /etc/syslog.conf chaudit w=sf,rx+f /etc/syslog.conf chmod 0744 /log_dir/log_file chaudit rwx=f /log_dir/log_file
Rating Info
DISA Cat II. NIST impact 3.
Expert Comment
None
ACF2-FT-000010: IBM z/OS SMF recording options for the FTP Server must be configured to write SMF records for all eligible events.
Refer to the FTP.DATA file specified on the SYSFTPD DD statement in the FTP started task JCL. The SYSFTPD DD statement is optional. The search order for FTP.DATA is: /etc/ftp.data SYSFTPD DD statement jobname.FTP.DATA SYS1.TCPPARMS(FTPDATA) tcpip.FTP.DATA If FTPDATA is configured with the following SMF statements, this is not a finding. FTP.DATA Configuration Statements SMF TYPE119 SMFJES TYPE119 SMFSQL TYPE119 SMFAPPE [Not coded or commented out] SMFDEL [Not coded or commented out] SMFEXIT [Not coded or commented out] SMFLOGN [Not coded or commented out] SMFREN [Not coded or commented out] SMFRETR [Not coded or commented out] SMFSTOR [Not coded or commented out]
Discussion
Without establishing when events occurred, it is impossible to establish, correlate, and investigate the events leading up to an outage or attack. In order to compile an accurate risk assessment and provide forensic analysis, it is essential for security personnel to know when events occurred (date and time). Associating event types with detected events in the operating system audit logs provides a means of investigating an attack; recognizing resource utilization or capacity thresholds; or identifying an improperly configured operating system. SMF data collection is the basic unit of tracking of all system functions and actions. Included in this tracking data are the audit records from each of the ACPs and system. If the required SMF data record types are not being collected, then accountability cannot be monitored, and its use in the execution of a contingency plan could be compromised. This requirement addresses auditing-related issues associated with maintenance tools used specifically for diagnostic and repair actions on organizational information systems. Nonlocal maintenance and diagnostic activities are those activities conducted by individuals communicating through a network, either an external network (e.g., the Internet) or an internal network. Local maintenance and diagnostic activities are those activities carried out by individuals physically present at the information system or information system component and not communicating across a network connection. This requirement applies to hardware/software diagnostic test equipment or tools. This requirement does not cover hardware/software components that may support information system maintenance, yet are a part of the system, for example, the software implementing "ping," "ls," "ipconfig," or the hardware and software implementing the monitoring port of an Ethernet switch. Satisfies: SRG-OS-000032-GPOS-00013, SRG-OS-000392-GPOS-00172
Fix
Configure SMF options to conform to the specifications in the FTPDATA Configuration Statements below or that they are commented out. SMF TYPE119 SMFJES TYPE119 SMFSQL TYPE119 SMFAPPE [Not coded or commented out] SMFDEL [Not coded or commented out] SMFEXIT [Not coded or commented out] SMFLOGN [Not coded or commented out] SMFREN [Not coded or commented out] SMFRETR [Not coded or commented out] SMFSTOR [Not coded or commented out] The FTP Server can provide audit data in the form of SMF records. SMF record type 119, the TCP/IP Statistics record, can be written with the following subtypes: 70 - Append 70 - Delete and Multiple Delete 72 - Invalid Logon Attempt 70 - Rename 70 - Get (Retrieve) and Multiple Get 70 - Put (Store and Store Unique) and Multiple Put SMF data produced by the FTP Server provides transaction information for both successful and unsuccessful FTP commands. This data may provide valuable information for security audit activities. Type 119 records use a more standard format and provide more information.
Rating Info
DISA Cat II. NIST impact 3.
Expert Comment
None
ACF2-ES-000020: The number of ACF2 users granted the special privilege PPGM must be justified.
From the ISPF Command Shell enter: SET LID SET VERBOSE LIST IF(PPGM) If the number of users granted the special privilege PPGM is strictly controlled and limited to systems programmer and operations personnel, this is not a finding.
Discussion
To mitigate the risk of unauthorized access to sensitive information by entities that have been issued certificates by DoD-approved PKIs, all DoD systems (e.g., web servers and web portals) must be properly configured to incorporate access control methods that do not rely solely on the possession of a certificate for access. Successful authentication must not automatically give an entity access to an asset or security boundary. Authorization procedures and controls must be implemented to ensure each authenticated entity also has a validated and current authorization. Authorization is the process of determining whether an entity, once authenticated, is permitted to access a specific asset. Information systems use access control policies and enforcement mechanisms to implement this requirement. Access control policies include: identity-based policies, role-based policies, and attribute-based policies. Access enforcement mechanisms include: access control lists, access control matrices, and cryptography. These policies and mechanisms must be employed by the application to control access between users (or processes acting on behalf of users) and objects (e.g., devices, files, records, processes, programs, and domains) in the information system.
Fix
Ensure that access to the special privilege PPGM is kept to a minimum and limited to systems programmer and operations personnel.
Rating Info
DISA Cat II. NIST impact 3.
Expert Comment
None
ACF2-OS-002360: IBM z/OS must employ a session manager to manage session lock after a 15-minute period of inactivity.
Ask the system administrator for the configuration parameters for the session manager in use. If there is no session manager in use, this is a finding. If the session manager is not configured to initiate session lock after a 15-minute period of inactivity this is a finding.
Discussion
A session lock is a temporary action taken when a user stops work and moves away from the immediate physical vicinity of the information system but does not want to log out because of the temporary nature of the absence. The session lock is implemented at the point where session activity can be determined. Regardless of where the session lock is determined and implemented, once invoked, the session lock must remain in place until the user reauthenticates. No other activity aside from reauthentication must unlock the system.
Fix
Configure the session manager to initiate a session lock after a 15-minute period of inactivity.
Rating Info
DISA Cat II. NIST impact 3.
Expert Comment
None
ACF2-ES-000240: CA-ACF2 must limit Write or greater access to SYS1.NUCLEUS to system programmers only.
If all of the following are untrue, this is not a finding. If any of the following is true, this is a finding. The ACP data set rules for SYS1.NUCLEUS do not restrict WRITE and/or ALLOCATE access to only z/OS systems programming personnel. The ACP data set rules for SYS1.NUCLEUS do not specify that all (i.e., failures and successes) WRITE and/or ALLOCATE access will be logged.
Discussion
To mitigate the risk of unauthorized access to sensitive information by entities that have been issued certificates by DoD-approved PKIs, all DoD systems (e.g., web servers and web portals) must be properly configured to incorporate access control methods that do not rely solely on the possession of a certificate for access. Successful authentication must not automatically give an entity access to an asset or security boundary. Authorization procedures and controls must be implemented to ensure each authenticated entity also has a validated and current authorization. Authorization is the process of determining whether an entity, once authenticated, is permitted to access a specific asset. Information systems use access control policies and enforcement mechanisms to implement this requirement. Access control policies include: identity-based policies, role-based policies, and attribute-based policies. Access enforcement mechanisms include: access control lists, access control matrices, and cryptography. These policies and mechanisms must be employed by the application to control access between users (or processes acting on behalf of users) and objects (e.g., devices, files, records, processes, programs, and domains) in the information system. Satisfies: SRG-OS-000080-GPOS-00048, SRG-OS-000259-GPOS-00100, SRG-OS-000324-GPOS-00125
Fix
Review access authorization to critical system files. Evaluate the impact of correcting the deficiency. Develop a plan of action and implement the changes required to protect SYS1.NUCLEUS. Configure the update and allocate access to SYS1.NUCLEUS to be limited to system programmers only and all update and allocate access is logged.
Rating Info
DISA Cat I. NIST impact 4.
Expert Comment
None
ACF2-FT-000080: The IBM z/OS TFTP Server program must be properly protected.
From the ACF Command screen enter: SET CONTROL(GSO) LIST LIKE(PPGM-) If Programs TFTPD and EZATD are not defined in the GSO PPGM record, this is a finding. From the ACF Command screen enter: SET RESOURCE(PGM) LIST LIKE(-) If Program resources TFTPD and EZATD are not defined in the PROGRAM resource class, this is a finding. If No access to the program resources TFTPD and EZATD is permitted, this is not a finding.
Discussion
Control of program execution is a mechanism used to prevent execution of unauthorized programs. Some operating systems may provide a capability that runs counter to the mission or provides users with functionality that exceeds mission requirements. This includes functions and services installed at the operating system level. Some of the programs, installed by default, may be harmful or may not be necessary to support essential organizational operations (e.g., key missions, functions). Removal of executable programs is not always possible; therefore, establishing a method of preventing program execution is critical to maintaining a secure system baseline. Methods for complying with this requirement include restricting execution of programs in certain environments, while preventing execution in other environments; or limiting execution of certain program functionality based on organization-defined criteria (e.g., privileges, subnets, sandboxed environments, or roles).
Fix
Configure the resource controls for the TFTP Server programs TFTPD and EZATD and ensure all access is restricted. Evaluate the impact of implementing the following change. Develop a plan of action and implement the change as required. Configure the resource controls for the TFTP Server programs TFTPD and EZATD and ensure all access is restricted. Examples: SET CONTROL(GSO) CHANGE PPGM PGM-MASK(TFTPD EZATD) ADD F ACF2,REFRESH(PPGM) $KEY(TFTPD) TYPE(PGM) UID(*) PREVENT SET R(PGM) COMPILE 'ACF2.MVA.PGM(TFTPD)' STORE F ACF2,REBUILD(PGM) $KEY(EZATD) TYPE(PGM) UID(*) PREVENT SET R(PGM) COMPILE 'ACF2.MVA.PGM(EZATD)' STORE F ACF2,REBUILD(PGM)
Rating Info
DISA Cat II. NIST impact 3.
Expert Comment
None
ACF2-ES-000860: ACF2 PSWD GSO record value must be set to require at least one lowercase character be used.
From the ISPF Command Shell enter: ACF to enter ACF2 Command shell enter SET CONTROL(GSO) LIST PSWD If "NOPSWDLC" is listed, this is a finding.
Discussion
Use of a complex password helps to increase the time and resources required to compromise the password. Password complexity, or strength, is a measure of the effectiveness of a password in resisting attempts at guessing and brute-force attacks. Password complexity is one factor of several that determines how long it takes to crack a password. The more complex the password, the greater the number of possible combinations that need to be tested before the password is compromised.
Fix
Configure the GSO option "PSWDLC" to "YES".
Rating Info
DISA Cat II. NIST impact 3.
Expert Comment
None
ACF2-ES-000310: CA-ACF2 must limit Write and allocate access to all system-level product installation libraries to system programmers only.
Have the systems programmer for z/OS supply the following information: - The data set name and associated SREL for each SMP/E CSI used to maintain this system. - The data set name of all SMP/E TLIBs and DLIBs used for installation and production support. A comprehensive list of the SMP/E DDDEFs for all CSIs may be used if valid. The ACF2 data set rules for system-level product installation libraries (e.g., SMP/E CSIs) do not restrict WRITE and/or ALLOCATE access to only z/OS systems programming personnel. If all of the above are untrue, this is not a finding. If any of the above is true, or if these data sets cannot be identified due to a lack of requested information, this is a finding.
Discussion
To mitigate the risk of unauthorized access to sensitive information by entities that have been issued certificates by DoD-approved PKIs, all DoD systems (e.g., web servers and web portals) must be properly configured to incorporate access control methods that do not rely solely on the possession of a certificate for access. Successful authentication must not automatically give an entity access to an asset or security boundary. Authorization procedures and controls must be implemented to ensure each authenticated entity also has a validated and current authorization. Authorization is the process of determining whether an entity, once authenticated, is permitted to access a specific asset. Information systems use access control policies and enforcement mechanisms to implement this requirement. Access control policies include: identity-based policies, role-based policies, and attribute-based policies. Access enforcement mechanisms include: access control lists, access control matrices, and cryptography. These policies and mechanisms must be employed by the application to control access between users (or processes acting on behalf of users) and objects (e.g., devices, files, records, processes, programs, and domains) in the information system. Satisfies: SRG-OS-000080-GPOS-00048, SRG-OS-000259-GPOS-00100, SRG-OS-000324-GPOS-00125
Fix
Review access authorization to critical system files. Evaluate the impact of correcting the deficiency. Develop a plan of action and implement the changes as required to protect System-level product installation libraries. Configure allocate access to all system-level product execution libraries to be limited to system programmers only.
Rating Info
DISA Cat II. NIST impact 3.
Expert Comment
None
ACF2-ES-000190: IBM z/OS Libraries included in the system REXXLIB concatenation must be properly protected.
Refer to AXRxx member of PARMLIB For each REXXLIB ADD statement If the ESM data set rules for libraries in the REXXLIB concatenation restrict WRITE or greater access to only z/OS systems programming personnel, this is not a finding. If the ESM data set rules for libraries in the REXXLIB concatenation restrict READ access to the following, this is not a finding. Appropriate Started Tasks Auditors The user-id defined in PARMLIB member AXR00 AXRUSER(user-id) If the ESM data set rules for libraries in the REXXLIB concatenation specify that all (i.e., failures and successes) WRITE or greater access will be logged, this is not a finding.
Discussion
To mitigate the risk of unauthorized access to sensitive information by entities that have been issued certificates by DoD-approved PKIs, all DoD systems (e.g., web servers and web portals) must be properly configured to incorporate access control methods that do not rely solely on the possession of a certificate for access. Successful authentication must not automatically give an entity access to an asset or security boundary. Authorization procedures and controls must be implemented to ensure each authenticated entity also has a validated and current authorization. Authorization is the process of determining whether an entity, once authenticated, is permitted to access a specific asset. Information systems use access control policies and enforcement mechanisms to implement this requirement. Access control policies include: identity-based policies, role-based policies, and attribute-based policies. Access enforcement mechanisms include: access control lists, access control matrices, and cryptography. These policies and mechanisms must be employed by the application to control access between users (or processes acting on behalf of users) and objects (e.g., devices, files, records, processes, programs, and domains) in the information system. Satisfies: SRG-OS-000080-GPOS-00048, SRG-OS-000324-GPOS-00125
Fix
Evaluate the impact of correcting the deficiency. Develop a plan of action and implement the changes required to protect APF Authorized Libraries. Configure ESM data set rules to limit WRITE or greater access to libraries included in the system REXXLIB concatenation to system programmers only. Configure ESM data set rules allow READ access to only appropriate Started Tasks and Auditors. Configure ESM data set rules to log UPDATE and/or ALTER access (i.e., successes and failures).
Rating Info
DISA Cat I. NIST impact 4.
Expert Comment
None
ACF2-ES-000140: CA-ACF2 allocate access to system user catalogs must be properly protected.
From the ISPF Command Shell, enter: LISTCat USERCATALOG NAME NOPREFIX Review the ACF2 data set rules for each usercatalog defined. If the data set rules for User Catalogs do not restrict ALLOCATE access to only z/OS systems programming personnel, this is a finding. If products or procedures requiring system programmer access for system-level maintenance meet the following specific case: - The batch job or procedure must be documented in the SITE Security Plan. - Reside in a data set that is restricted to systems programmers' access only. If the above is true, this is not a finding. If the data set rules for User Catalogs do not specify that all (i.e., failures and successes) ALLOCATE access will be logged, this is a finding. Note: If the USER CATALOGS contain SMS managed data sets, READ access is sufficient to allow user operations. If the USER CATALOGS do not contain SMS managed datasets, WRITE access is required for user operation.
Discussion
Access control policies include: identity-based policies, role-based policies, and attribute-based policies. Access enforcement mechanisms include: access control lists, access control matrices, and cryptography. These policies and mechanisms must be employed by the application to control access between users (or processes acting on behalf of users) and objects (e.g., devices, files, records, processes, programs, and domains) in the information system.
Fix
Review access authorization to critical system files. Evaluate the impact of correcting the deficiency. Develop a plan of action and implement the changes as required to protect USER CATALOGS. Configure ACF2 rules for allocate access to USER CATALOGS, limited to system programmers only, and all allocate access is logged. Configure ACF2 rules for the USER CATALOGS to allow any Products or procedures system programmer access for system-level maintenance that meets the following specific case: - The batch job or procedure must be documented in the SITE Security Plan. - Reside in a data set that is restricted to systems programmers' access only. Note: If the USER CATALOGS contain SMS managed data sets READ access is sufficient to allow user operations. If the USER CATALOGS do not contain SMS managed datasets WRITE access is required for user operation.
Rating Info
DISA Cat II. NIST impact 3.
Expert Comment
None
ACF2-ES-000810: CA-ACF2 PWPHRASE GSO record must be properly defined.
From the ISPF Command Screen enter: ACF SET CONTROL(GSO) LIST PWPHRASE If the following options are in effect, this is not a finding. If any of the options deviate from the following, this is a finding. The GSO PWPHRASE record will conform to the following requirements. ALPHA(1 or greater) HISTORY(10-32) MAXDAYS(1-60) MINDAYS(1) MINLEN(15-100) NUMERIC(1 or greater) SPECIAL(1 or greater) SPECLIST(character list) WARNDAYS(1-10) Note: The SPECLIST special characters will be specified at a minimum. Characters will conform to the allowable list defined in CA ACF2 for z/OS Administration Guide.
Discussion
Use of a complex password helps to increase the time and resources required to compromise the password. Password complexity or strength is a measure of the effectiveness of a password in resisting attempts at guessing and brute-force attacks. Password complexity is one factor in determining how long it takes to crack a password. The more complex the password, the greater the number of possible combinations that need to be tested before the password is compromised. Special characters are those characters that are not alphanumeric. Examples include: ~ ! @ # $ % ^ *.
Fix
Configure the PWPHRASE GSO values to be set to the values specified. Ensure the GSO PWPHRASE record values conform to the following requirements: ALPHA(1 or greater) HISTORY(10-32) MAXDAYS(1-60) MINDAYS(1) MINLEN(15-100) NUMERIC(1 or greater) SPECIAL(1 or greater) SPECLIST(character list) WARNDAYS(1-10) Note: The SPECLIST special characters will be specified at a minimum. Characters will conform to the allowable list defined in CA ACF2 for z/OS Administration Guide. Example: SET C(GSO) INSERT PWPHRASE NOALLOW ALPHA(1) HISTORY(10) MAXDAYS(60) MINDAYS(1) MINLEN(15) NUMERIC(1) SPECIAL(1) SPECLIST(& * =) WARNDAYS(10) F ACF2,REFRESH(PWPHRASE)
Rating Info
DISA Cat II. NIST impact 3.
Expert Comment
None
ACF2-ES-000430: The CA-ACF2 PSWD GSO record values for MAXTRY and PASSLMT must be properly set.
From an ACF command screen enter: SET CONTROL(GSO) SHOW PSwdopts If "MAXTRY" is set to "3", this is not a finding. If "PASSLMT" is set to "3", this is not a finding.
Discussion
By limiting the number of failed logon attempts, the risk of unauthorized system access via user password guessing, otherwise known as brute-forcing, is reduced. Limits are imposed by locking the account.
Fix
Configure the GSO option "MAXTRY" to equal "3". Configure the GSO option "PASSLMT" to equal "3".
Rating Info
DISA Cat II. NIST impact 3.
Expert Comment
None
ACF2-OS-002370: IBM z/OS System Administrator must develop a procedure to automatically remove or disable temporary user accounts after 72 hours.
Ask the system administrator for the procedure to automatically remove or disable temporary user accounts after 72 hours. If there is no procedure, this is a finding.
Discussion
If temporary user accounts remain active when no longer needed or for an excessive period, these accounts may be used to gain unauthorized access. To mitigate this risk, automated termination of all temporary accounts must be set upon account creation. Temporary accounts are established as part of normal account activation procedures when there is a need for short-term accounts without the demand for immediacy in account activation. If temporary accounts are used, the operating system must be configured to automatically terminate these types of accounts after a DoD-defined time period of 72 hours. To address access requirements, many operating systems may be integrated with enterprise-level authentication/access mechanisms that meet or exceed access control policy requirements.
Fix
Develop a procedure to automatically remove or disable temporary user accounts after 72 hours.
Rating Info
DISA Cat II. NIST impact 3.
Expert Comment
None
ACF2-ES-000940: ACF2 TSO2741 GSO record values must be set to obliterate the logon password on 2741 devices.
From the ISPF Command Shell enter: ACF <enter> SET CONTROL(GSO) LIST TSO2741 If the GSO TSO2741 record values conform to the following requirements, this is not a finding. BS(16) LENGTH(8) M1(X) M2(N) M3(Z) M4(M) STRING()
Discussion
To prevent the compromise of authentication information, such as passwords during the authentication process, the feedback from the operating system must not provide any information allowing an unauthorized user to compromise the authentication mechanism.
Fix
Define a cross out string used to obliterate the logon password on 2741 devices. Ensure the GSO TSO2741 record values conform to the following requirements. BS(16) LENGTH(8) M1(X) M2(N) M3(Z) M4(M) STRING() Example: SET C(GSO) INSERT TSO2741 BS(16) LENGTH(8) M1(X) M2(N) M3(Z) M4(M) STRING() F ACF2,REFRESH(TSO2741)
Rating Info
DISA Cat II. NIST impact 3.
Expert Comment
None
ACF2-US-000160: IBM z/OS UNIX BPXPRMxx security parameters in PARMLIB must be properly specified.
Refer to the proper BPXPRMxx member in SYS1.PARMLIB. If the required parameter keywords and values are defined as detailed below, this is not a finding. Parameter Keyword Value SUPERUSER BPXROOT TTYGROUP TTY STEPLIBLIST /etc/steplib USERIDALIASTABLE will not be specified. ROOT SETUID will be specified. MOUNT NOSETUID SETUID (for Vendor-provided files) SECURITY STARTUP_PROC OMVS
Discussion
Configuration settings are the set of parameters that can be changed in hardware, software, or firmware components of the system that affect the security posture and/or functionality of the system. Security-related parameters are those parameters impacting the security state of the system, including the parameters required to satisfy other security control requirements. Security-related parameters include, for example: registry settings; account, file, directory permission settings; and settings for functions, ports, protocols, services, and remote connections.
Fix
Define the settings in PARMLIB member BPXPRMxx for z/OS UNIX security parameters values to conform to the specifications below: Parameter Keyword Value SUPERUSER BPXROOT TTYGROUP TTY STEPLIBLIST /etc/steplib USERIDALIASTABLE will not be specified. ROOT SETUID will be specified. MOUNT NOSETUID SETUID (for Vendor-provided files) SECURITY STARTUP_PROC OMVS
Rating Info
DISA Cat II. NIST impact 3.
Expert Comment
None
ACF2-US-000100: IBM z/OS UNIX HFS permission bits and audit bits for each directory must be properly protected.
From the ISPF Command Shell enter: omvs cd / ls -alW If the HFS permission bits and user audit bits for each directory and file match or are more restrictive than the specified settings listed in the Tale below, this is not a finding. SYSTEM DIRECTORY SECURITY SETTINGS DIRECTORY PERMISSION BITS USER AUDIT BITS FUNCTION / [root] 755 faf Root level of all file systems. Holds critical mount points. /bin 1755 fff Shell scripts and executables for basic functions /dev 1755 fff Character-special files used when logging into the OMVS shell and during C language program compilation. Files are created during system IPL and on a per-demand basis. /etc 1755 faf Configuration programs and files (usually with locally customized data) used by z/OS UNIX and other product initialization processes /lib 1755 fff System libraries including dynamic link libraries and files for static linking /samples 1755 fff Sample configuration and other files /tmp 1777 fff Temporary data used by daemons, servers, and users. Note: /tmp must have the sticky bit on to restrict file renames and deletions. /u 1755 fff Mount point for user home directories and optionally for third-party software and other local site files /usr 1755 fff Shell scripts, executables, help (man) files and other data. Contains sub-directories (e.g., lpp) and mount points used by program products that may be in separate file systems. /var 1775 fff Dynamic data used internally by products and by elements and features of z/OS UNIX. The following represents a hierarchy for permission bits from least restrictive to most restrictive: 7 rwx (least restrictive) 6 rw- 3 -wx 2 -w- 5 r-x 4 r-- 1 --x 0 --- (most restrictive) The possible audit bits settings are as follows: f log for failed access attempts a log for failed and successful access - no auditing
Discussion
To mitigate the risk of unauthorized access to sensitive information by entities that have been issued certificates by DoD-approved PKIs, all DoD systems (e.g., web servers and web portals) must be properly configured to incorporate access control methods that do not rely solely on the possession of a certificate for access. Successful authentication must not automatically give an entity access to an asset or security boundary. Authorization procedures and controls must be implemented to ensure each authenticated entity also has a validated and current authorization. Authorization is the process of determining whether an entity, once authenticated, is permitted to access a specific asset. Information systems use access control policies and enforcement mechanisms to implement this requirement. Satisfies: SRG-OS-000080-GPOS-00048, SRG-OS-000259-GPOS-00100
Fix
Define the UNIX permission bits and user audit bits on each of the HFS directory in the table below to be equal or more restrictive. SYSTEM DIRECTORY SECURITY SETTINGS DIRECTORY PERMISSION BITS USER AUDIT BITS FUNCTION / [root] 755 faf Root level of all file systems. Holds critical mount points. /bin 1755 fff Shell scripts and executables for basic functions /dev 1755 fff Character-special files used when logging into the OMVS shell and during C language program compilation. Files are created during system IPL and on a per-demand basis. /etc 1755 faf Configuration programs and files (usually with locally customized data) used by z/OS UNIX and other product initialization processes /lib 1755 fff System libraries including dynamic link libraries and files for static linking /samples 1755 fff Sample configuration and other files /tmp 1777 fff Temporary data used by daemons, servers, and users. Note: /tmp must have the sticky bit on to restrict file renames and deletions. /u 1755 fff Mount point for user home directories and optionally for third-party software and other local site files /usr 1755 fff Shell scripts, executables, help (man) files and other data. Contains sub-directories (e.g., lpp) and mount points used by program products that may be in separate file systems. /var 1775 fff Dynamic data used internally by products and by elements and features of z/OS UNIX. The following represents a hierarchy for permission bits from least restrictive to most restrictive: 7 rwx (least restrictive) 6 rw- 3 -wx 2 -w- 5 r-x 4 r-- 1 --x 0 --- (most restrictive) The possible audit bits settings are as follows: f log for failed access attempts a log for failed and successful access - no auditing The following commands are a sample of the commands to be used (from a user account with an effective UID(0)) to update the permission bits and audit bits: chmod 0755 / chaudit w=sf,rx+f / chmod 0755 /bin chaudit rwx=f /bin
Rating Info
DISA Cat II. NIST impact 3.
Expert Comment
None
ACF2-US-000220: IBM z/OS Attributes of z/OS UNIX user accounts must have a unique GID in the range of 1-99.
From the ISPF Command Shell enter: ACF SET PROFILE(GROUP) DIVISION(OMVS) LIST LIKE(-) If OMVSGRP and/or STCOMVS groups are defined and have a unique GID in the range of 1-99, this is not a finding.
Discussion
To assure accountability and prevent unauthenticated access, organizational users must be identified and authenticated to prevent potential misuse and compromise of the system. Organizational users include organizational employees or individuals the organization deems to have equivalent status of employees (e.g., contractors). Organizational users (and processes acting on behalf of users) must be uniquely identified and authenticated to all accesses, except for the following: 1) Accesses explicitly identified and documented by the organization. Organizations document specific user actions that can be performed on the information system without identification or authentication; and 2) Accesses that occur through authorized use of group authenticators without individual authentication. Organizations may require unique identification of individuals in group accounts (e.g., shared privilege accounts) or for detailed accountability of individual activity.
Fix
Define the OMVSGRP group and / or the STCOMVS group to the security database with a unique GID in the range of 1-99. OMVSGRP is the name suggested by IBM for all the required userids. STCOMVS is the standard name used at some sites for the userids that are associated with z/OS UNIX started tasks and daemons. These groups can be combined at the site's discretion.
Rating Info
DISA Cat II. NIST impact 3.
Expert Comment
None
ACF2-ES-000770: IBM z/OS user account for the UNIX (RMFGAT) must be properly defined.
RMFGAT is the userid for the Resource Measurement Facility (RMF) Monitor III Gatherer. If RMFGAT is not define, this is Not Applicable. From the ISPF Command Shell enter: ACF SET LID SET VERBOSE LIST RMFGAT SECTION(ALL) PROFILE(OMVS) If RMFGAT is defined as follows, this is not a finding: Default group specified as OMVSGRP or STCOMVS A unique, non-zero UID HOME directory specified as "/" Shell program specified as "/bin/sh"
Discussion
To assure accountability and prevent unauthenticated access, organizational users must be identified and authenticated to prevent potential misuse and compromise of the system. Organizational users include organizational employees or individuals the organization deems to have equivalent status of employees (e.g., contractors). Organizational users (and processes acting on behalf of users) must be uniquely identified and authenticated to all accesses, except for the following: 1) Accesses explicitly identified and documented by the organization. Organizations document specific user actions that can be performed on the information system without identification or authentication; and 2) Accesses that occur through authorized use of group authenticators without individual authentication. Organizations may require unique identification of individuals in group accounts (e.g., shared privilege accounts) or for detailed accountability of individual activity.
Fix
Define the RMFGAT user account as specified below: Default group specified as OMVSGRP or STCOMVS A unique, non-zero UID HOME directory specified as "/" Shell program specified as "/bin/sh"
Rating Info
DISA Cat II. NIST impact 3.
Expert Comment
None
ACF2-ES-000180: IBM z/OS must protect dynamic lists in accordance with proper security requirements.
From a command input screen enter: SET RESOURCE (FAC) SET VERBOSE LIST LIKE (CSV-) NOTE: If CLASMAP defines FACILITY as anything other than the default of TYPE(FAC), replace FAC with the appropriate three letters. If the ACF2 resources and/or generic equivalent are defined with a default access of PREVENT, this is not a finding. If the ACF2 resources and/or generic equivalent identified below will be defined with LOG and SERVICE(UPDATE) access restricted to system programming personnel, this is not a finding. CSVAPF. CSVAPF.MVS.SETPROG.FORMAT.DYNAMIC CSVAPF.MVS.SETPROG.FORMAT.STATIC CSVDYLPA. CSVDYNEX. CSVDYNEX.LIST CSVDYNL. CSVDYNL.UPDATE.LNKLST CSVLLA. If the ACF2 CSVDYNEX.LIST resource and/or generic equivalent will be defined with LOG and SERVICE(UPDATE) access restricted to system programming personnel, this is not a finding. If the ACF2 CSVDYNEX.LIST resource and/or generic equivalent will be defined with SERVICE(READ) access restricted to auditors, this is not a finding. If the products CICS and/or CONTROL-O are on the system, the ACF2 access to the CSVLLA resource and/or generic equivalent will be defined with LOG and SERVICE(UPDATE) access restricted to the CICS and CONTROL-O STC logonids, this is not a finding. If any software product requires access to dynamic LPA updates on the system, the ACF2 access to the CSVDYLPA resource and/or generic equivalent will be defined with LOG and SERVICE(UPDATE) only after the product has been validated with the appropriate STIG or SRG for compliance AND receives documented and filed authorization that details the need and any accepted risks from the site ISSM or equivalent security authority, this is not a finding. Note: In the above, SERVICE(UPDATE) can be substituted with ADD, CONTROL, or LOG/ALLOW. Review the rules definitions in the ACF2 documentation when specifying SERVICE(UPDATE).
Discussion
To mitigate the risk of unauthorized access to sensitive information by entities that have been issued certificates by DoD-approved PKIs, all DoD systems (e.g., web servers and web portals) must be properly configured to incorporate access control methods that do not rely solely on the possession of a certificate for access. Successful authentication must not automatically give an entity access to an asset or security boundary. Authorization procedures and controls must be implemented to ensure each authenticated entity also has a validated and current authorization. Authorization is the process of determining whether an entity, once authenticated, is permitted to access a specific asset. Information systems use access control policies and enforcement mechanisms to implement this requirement. Access control policies include: identity-based policies, role-based policies, and attribute-based policies. Access enforcement mechanisms include: access control lists, access control matrices, and cryptography. These policies and mechanisms must be employed by the application to control access between users (or processes acting on behalf of users) and objects (e.g., devices, files, records, processes, programs, and domains) in the information system. Satisfies: SRG-OS-000080-GPOS-00048, SRG-OS-000324-GPOS-00125
Fix
Configure the Dynamic List resources to be defined to the IBMFAC resource class and protected. Only system programmers and a limited number of authorized users and Approved authorized Started Tasks are able to issue these commands. All access is logged. Note: The resource class, resources, and/or resource prefixes identified below are examples of a possible installation. The resource class, actual resources, and/or prefixes are determined when the product is actually installed on a system through the product's installation guide and can be site specific. The required CSV-prefixed Facility Class resources are listed below. These resources and/or generic equivalents should be defined and permitted as required with only z/OS systems programmers and logging enabled. Minimum required list of CSV-prefixed resources: CSVAPF.- CSVAPF.MVS.SETPROG.FORMAT.DYNAMIC CSVAPF.MVS.SETPROG.FORMAT.STATIC CSVDYLPA.- CSVDYLPA.ADD.- CSVDYLPA.DELETE.- CSVDYNEX.- CSVDYNEX.LIST CSVDYNL.- CSVDYNL.UPDATE.LNKLST CSVLLA.- Limit authority to those resources to z/OS systems programmers. Restrict to the absolute minimum number of personnel with LOG and SERVICE(UPDATE) access. Sample commands are shown here to accomplish one set of resources: $KEY(CSVAPF) TYPE(FAC) MVS.SETPROG.- UID(sysprgmr) LOG MVS.SETPROG.FORMAT.DYNAMIC.- UID(sysprgmr) LOG MVS.SETPROG.FORMAT.STATIC.- UID(sysprgmr) LOG MVS.SETPROG.FORMAT.- UID(sysprgmr) LOG MVS.SETPROG.FORMAT.- UID(*) PREVENT - UID(sysprgmr) LOG - UID(*) PREVENT SET R(FAC) COMPILE 'ACF2.xxxx.FAC(CSVAPF)' STORE F ACF2,REBUILD(FAC) The CSVDYLPA.ADD resource can be permitted to BMC Mainview, CA 1, and CA Common Services STC logonids with LOG and SERVICE(UPDATE) access. The CSVDYLPA.DELETE resource can be permitted to CA 1 and CA Common Services STC logonids with LOG and SERVICE(UPDATE) access. Sample commands are shown here to accomplish one set of resources: $KEY(CSVDYLPA) TYPE(FAC) ADD.- UID(sysprgmr) LOG SERVICE(UPDATE) ADD.- UID(BMC Mainview STC) LOG SERVICE(UPDATE) ADD.- UID(CA 1 STC) LOG SERVICE(UPDATE) ADD.- UID(CCS STC) LOG SERVICE(UPDATE) DELETE.- UID(sysprgmr) LOG SERVICE(UPDATE) DELETE.- UID(CA 1 STC) LOG SERVICE(UPDATE) DELETE.- UID(CCS STC) LOG SERVICE(UPDATE) - UID(sysprgmr) LOG - UID(*) PREVENT SET R(FAC) COMPILE 'ACF2.xxxx.FAC(CSVDYLPA)' STORE F ACF2,REBUILD(FAC) The CSVDYNEX.LIST resource and/or generic equivalent will be defined with LOG and SERVICE(UPDATE) access restricted to system programming personnel. The CSVDYNEX.LIST resource and/or generic equivalent will be defined with SERVICE(READ) access with ALLOW restricted to auditors. Sample commands are shown here to accomplish this: $KEY(CSVDYNEX) TYPE(FAC) LIST.- UID(sysprgmr) LOG LIST.- UID(auditor) SERVICE(READ) ALLOW - UID(sysprgmr) LOG - UID(*) PREVENT SET R(FAC) COMPILE 'ACF2.xxxx.FAC(CSVDYNEX)' STORE F ACF2,REBUILD(FAC) The CSVLLA resource can be permitted to CICS and CONTROL-O STC logonids with LOG and SERVICE(UPDATE) access. Sample commands are shown here to accomplish one set of resources: $KEY(CSVLLA) TYPE(FAC) - UID(sysprgmr) LOG - UID(CICS STC logonids) LOG SERVICE(UPDATE) - UID(CONTROL-O STC logonid) LOG SERVICE(UPDATE) - UID(*) PREVENT SET R(FAC) COMPILE 'ACF2.xxxx.FAC(CSVLLA)' STORE F ACF2,REBUILD(FAC)
Rating Info
DISA Cat I. NIST impact 4.
Expert Comment
None
ACF2-US-000150: IBM z/OS UNIX HFS MapName files security parameters must be properly specified.
Refer to the logical parmlib data sets, example: SYS1.PARMLIB(BPXPRMxx), for the following FILESYSTYPE entry: FILESYSTYPE TYPE(AUTOMNT) ENTRYPOINT(BPXTAMD) If the above entry is not found or is commented out in the BPXPRMxx member(s), this is Not Applicable. From the ISPF Command Shell enter: OMVS cd /etc cat auto.master Perform a contents list for the file identified. Example: cat u.map Note: The /etc/auto.master HFS file (and the use of Automount) is optional. If the file does not exist, this is Not Applicable. Note: The setuid parameter and the security parameter have a significant security impact. For this reason these parameters must be explicitly specified and not allowed to default. If each MapName file specifies the "setuid No" and "security Yes" statements for each automounted directory, this is not a finding. If there is any deviation from the required values, this is a finding.
Discussion
Removal of unneeded or non-secure functions, ports, protocols, and services mitigate the risk of unauthorized connection of devices, unauthorized transfer of information, or other exploitation of these resources. The organization must perform a periodic scan/review of the application (as required by CCI-000384) and disable functions, ports, protocols, and services deemed to be unneeded or non-secure.
Fix
Review the settings in /etc/auto.master and /etc/mapname for z/OS UNIX security parameters and configure the values to conform to the specifications below. The /etc/auto.master HFS file (and the use of Automount) is optional. The setuid parameter and the security parameter have a significant security impact. For this reason these parameters must be explicitly specified and not be allowed to default. Each MapName file will specify the "setuid NO" and "security YES" statements for each automounted directory. If there is a deviation from the required values, documentation must exist for the deviation. Security NO disables security checking for file access. Security NO is only allowed on test and development domains. Setuid YES allows a user to run under a different UID/GID identity. Justification documentation is required to validate the use of setuid YES.
Rating Info
DISA Cat II. NIST impact 3.
Expert Comment
None
ACF2-US-000190: IBM z/OS user account for the z/OS UNIX SUPERSUSER userid must be properly defined.
Refer to system PARMLIB member BPXPRMxx (xx is determined by OMVS entry in IEASYS00.) Determine the user ID identified by the SUPERUSER parameter. (BPXROOT is the default). From a command input screen enter: SET LID LIST LIKE (superuser userid) If the SUPERUSER userid is defined as follows, this is not a finding. - No access to interactive on-line facilities (e.g., TSO, CICS, etc.) - Default group specified as OMVSGRP or STCOMVS From an ACF command input screen enter: SET PROFILE(USER) DIVISION(OMVS) SET VERBOSE LIST <superuser userid> If the SUPERUSER userid is defined as follows, this is not a finding: - UID(0) - HOME directory specified as "/" - Shell program specified as "/bin/sh"
Discussion
To assure accountability and prevent unauthenticated access, organizational users must be identified and authenticated to prevent potential misuse and compromise of the system. Organizational users include organizational employees or individuals the organization deems to have equivalent status of employees (e.g., contractors). Organizational users (and processes acting on behalf of users) must be uniquely identified and authenticated to all accesses, except for the following: 1) Accesses explicitly identified and documented by the organization. Organizations document specific user actions that can be performed on the information system without identification or authentication; and 2) Accesses that occur through authorized use of group authenticators without individual authentication. Organizations may require unique identification of individuals in group accounts (e.g., shared privilege accounts) or for detailed accountability of individual activity.
Fix
Define the user ID identified in the BPXPRM00 SUPERUSER parameter as specified below: No access to interactive on-line facilities (e.g., TSO, CICS, etc) Default group specified as OMVSGRP or STCOMVS UID(0) HOME directory specified as "/" Shell program specified as "/bin/sh"
Rating Info
DISA Cat II. NIST impact 3.
Expert Comment
None
ACF2-IC-000020: IBM Integrated Crypto Service Facility (ICSF) install data sets must be properly protected.
If the ESM dataset rules for the IBM Integrated Crypto Service Facility (ICSF) install data sets does not restrict UPDATE and/or ALTER access to systems programming personnel this is a finding. If the ESM data set rules for IBM Integrated Crypto Service Facility (ICSF) install data set does not specify that all (i.e., failures and successes) UPDATE and/or ALTER access will be logged this is a finding.
Discussion
IBM Integrated Crypto Service Facility (ICSF) product has the ability to use privileged functions and/or have access to sensitive data. Failure to properly restrict access to their data sets could result in violating the integrity of the base product which could result in compromising the operating system or sensitive data.
Fix
Ensure that update and allocate access to IBM Integrated Crypto Service Facility (ICSF) install data sets is limited to System Programmers only, and all update and allocate access is logged. Read access can be given to Auditors and any other users that have a valid requirement to utilize these data sets. The installing Systems Programmer will identify and document the product data sets and categorize them according to who will have update and alter access and if required that all update and allocate access is logged. He will identify if any additional groups have update access for specific data sets, and once documented he will work with the IAO to see that they are properly restricted to the ACP (Access Control Program) active on the system. Data sets to be protected will be: SYS1.CSF The following commands are provided as a sample for implementing data set controls: $KEY(SYS1) CSF.- UID(syspaudt) R(A) W(L) A(L) E(A) CSF.- UID(tstcaudt) R(A) W(L) A(L) E(A) CSF.- UID(icsfusrs) R(A) E(A)
Rating Info
DISA Cat II. NIST impact 3.
Expert Comment
None
ACF2-OS-000340: The IBM z/OS systems requiring data at rest protection must properly employ IBM DS8880 or equivalent hardware solutions for full disk encryption.
Determine if IBM's DS880 Disks or equivalent hardware solutions are in use. If they are not in use for systems that require data at rest, this is a finding.
Discussion
Information at rest refers to the state of information when it is located on a secondary storage device (e.g., disk drive and tape drive, when used for backups) within an operating system. This control addresses the confidentiality and integrity of information at rest and covers user information and system information. Information at rest refers to the state of information when it is located on storage devices as specific components of information systems. Operating systems handling data requiring "data at rest" protections must employ cryptographic mechanisms to prevent unauthorized disclosure and modification of the information at rest. Selection of a cryptographic mechanism is based on the need to protect the integrity of organizational information. The strength of the mechanism is commensurate with the security category and/or classification of the information. Organizations have the flexibility to either encrypt all information on storage devices (i.e., full disk encryption) or encrypt specific data structures (e.g., files, records, or fields). Use of weak or untested encryption algorithms undermines the purposes of utilizing encryption to protect data. The operating system must implement cryptographic modules adhering to the higher standards approved by the federal government since this provides assurance they have been tested and validated. Satisfies: SRG-OS-000185-GPOS-00079, SRG-OS-000405-GPOS-00184, SRG-OS-000404-GPOS-00183, SRG-OS-000396-GPOS-00176
Fix
Employ IBM's DS8880 hardware or equivalent hardware solutions to ensure full disk encryption.
Rating Info
DISA Cat I. NIST impact 4.
Expert Comment
None
ACF2-ES-000040: The number of ACF2 users granted the special privilege CONSOLE must be justified.
From the ISPF Command Shell enter: ACF SET LID SET VERBOSE LIST IF(ACCTPRIV OR CONSOLE OR OPERATOR OR MOUNT) If the number of users granted the special privilege CONSOLE is strictly controlled (issued on an as-needed basis), this is not a finding. If the number of users granted the special privilege CONSOLE is not strictly controlled (issued on an as-needed basis), this is a finding.
Discussion
To mitigate the risk of unauthorized access to sensitive information by entities that have been issued certificates by DoD-approved PKIs, all DoD systems (e.g., web servers and web portals) must be properly configured to incorporate access control methods that do not rely solely on the possession of a certificate for access. Successful authentication must not automatically give an entity access to an asset or security boundary. Authorization procedures and controls must be implemented to ensure each authenticated entity also has a validated and current authorization. Authorization is the process of determining whether an entity, once authenticated, is permitted to access a specific asset. Information systems use access control policies and enforcement mechanisms to implement this requirement. Access control policies include: identity-based policies, role-based policies, and attribute-based policies. Access enforcement mechanisms include: access control lists, access control matrices, and cryptography. These policies and mechanisms must be employed by the application to control access between users (or processes acting on behalf of users) and objects (e.g., devices, files, records, processes, programs, and domains) in the information system.
Fix
Define the CONSOLE attribute with minimum access and it is controlled and documented. Documentation providing justification for access is maintained and filed with the ISSO and that unjustified access is removed.
Rating Info
DISA Cat III. NIST impact 2.
Expert Comment
None
ACF2-ES-000280: CA-ACF2 must limit Write and Allocate access to all APF-authorized libraries to system programmers only.
From Any ISPF input line, enter: TSO ISRDDN APF If all of the following are untrue, this is not a finding. If any of the following is true, this is a finding. - The ACP data set rules for APF libraries do not restrict WRITE and/or ALLOCATE access to only z/OS systems programming personnel. - The ACP data set rules for APF libraries do not specify that all (i.e., failures and successes) WRITE and/or ALLOCATE access will be logged.
Discussion
To mitigate the risk of unauthorized access to sensitive information by entities that have been issued certificates by DoD-approved PKIs, all DoD systems (e.g., web servers and web portals) must be properly configured to incorporate access control methods that do not rely solely on the possession of a certificate for access. Successful authentication must not automatically give an entity access to an asset or security boundary. Authorization procedures and controls must be implemented to ensure each authenticated entity also has a validated and current authorization. Authorization is the process of determining whether an entity, once authenticated, is permitted to access a specific asset. Information systems use access control policies and enforcement mechanisms to implement this requirement. Access control policies include: identity-based policies, role-based policies, and attribute-based policies. Access enforcement mechanisms include: access control lists, access control matrices, and cryptography. These policies and mechanisms must be employed by the application to control access between users (or processes acting on behalf of users) and objects (e.g., devices, files, records, processes, programs, and domains) in the information system. This requirement applies to operating systems with software libraries that are accessible and configurable, as in the case of interpreted languages. Software libraries also include privileged programs which execute with escalated privileges. Only qualified and authorized individuals must be allowed to obtain access to information system components for purposes of initiating changes, including upgrades and modifications. Satisfies: SRG-OS-000080-GPOS-00048, SRG-OS-000259-GPOS-00100, SRG-OS-000324-GPOS-00125
Fix
Review access authorization to critical system files. Evaluate the impact of correcting the deficiency. Develop a plan of action and implement the changes required to protect APF Authorized Libraries. Configure Update and Allocate access to all APF-authorized libraries to be limited to system programmers only and all update and alter access is logged.
Rating Info
DISA Cat I. NIST impact 4.
Expert Comment
None
ACF2-TC-000050: IBM z/OS data sets for the Base TCP/IP component must be properly protected.
If all of the following items are true, this is not a finding. WRITE and ALLOCATE access to product data sets is restricted to systems programming personnel (i.e., SMP/E distribution data sets with the prefix SYS1.TCPIP.AEZA and target data sets with the prefix SYS1.TCPIP.SEZA). WRITE and ALLOCATE access to the data set(s) containing the Data and Profile configuration files is restricted to systems programming personnel. Note: If any INCLUDE statements are specified in the Profile configuration file, the named MVS data sets have the same access authorization requirements. WRITE and ALLOCATE access to the data set(s) containing the Data and Profile configuration files is logged. Note: If any INCLUDE statements are specified in the Profile configuration file, the named MVS data sets have the same logging requirements. WRITE and ALLOCATE access to the data set(s) containing the configuration files shared by TCP/IP applications is restricted to systems programming personnel.
Discussion
MVS data sets of the Base TCP/IP component provide the configuration, operational, and executable properties of IBMs TCP/IP system product. Failure to properly secure these data sets may lead to unauthorized access resulting in the compromise of the integrity and availability of the operating system environment, ACP, and customer data. To mitigate the risk of unauthorized access to sensitive information by entities that have been issued certificates by DoD-approved PKIs, all DoD systems (e.g., web servers and web portals) must be properly configured to incorporate access control methods that do not rely solely on the possession of a certificate for access. Successful authentication must not automatically give an entity access to an asset or security boundary. Authorization procedures and controls must be implemented to ensure each authenticated entity also has a validated and current authorization. Authorization is the process of determining whether an entity, once authenticated, is permitted to access a specific asset. Information systems use access control policies and enforcement mechanisms to implement this requirement. Access control policies include: identity-based policies, role-based policies, and attribute-based policies. Access enforcement mechanisms include: access control lists, access control matrices, and cryptography. These policies and mechanisms must be employed by the application to control access between users (or processes acting on behalf of users) and objects (e.g., devices, files, records, processes, programs, and domains) in the information system. Satisfies: SRG-OS-000080-GPOS-00048, SRG-OS-000259-GPOS-00100
Fix
Review the data set access authorizations defined to the ACP for the Base TCP/IP component. Configure these data sets to be protected in accordance with the following rules: WRITE and ALLOCATE access to product data sets is restricted to systems programming personnel (i.e., SMP/E distribution data sets with the prefix SYS1.TCPIP.AEZA and target data sets with the prefix SYS1.TCPIP. SEZA). WRITE and ALLOCATE access to the data set(s) containing the Data and Profile configuration files is restricted to systems programming personnel. Note: If any INCLUDE statements are specified in the Profile configuration file, the named MVS data sets have the same access authorization requirements. WRITE and ALLOCATE access to the data set(s) containing the Data and Profile configuration files is logged. Note: If any INCLUDE statements are specified in the Profile configuration file, the named MVS data sets have the same logging requirements. WRITE and ALLOCATE access to the data set(s) containing the configuration files shared by TCP/IP applications is restricted to systems programming personnel.
Rating Info
DISA Cat II. NIST impact 3.
Expert Comment
None
ACF2-ES-000370: IBM z/OS IEASYMUP resource must be protected in accordance with proper security requirements.
From the ACF Command screen enter: SET RESOURCE(FAC) LIST IEASYMUP If the accesses for IEASYMUP resources and/or generic equivalent are properly restricted, this is not a finding. The ACF2 resources are defined with a default access of PREVENT. The ACF2 resource access authorizations specify SERVICE(UPDATE) and/or greater access to only DASD administrators, Tape Library personnel, and system programming personnel. The ACF2 resource access authorizations specify logging.
Discussion
Privileged functions include, for example, establishing accounts, performing system integrity checks, or administering cryptographic key management activities. Non-privileged users are individuals that do not possess appropriate authorizations. Circumventing intrusion detection and prevention mechanisms or malicious code protection mechanisms are examples of privileged functions that require protection from non-privileged users.
Fix
Configure the System level symbolic resources to be defined to the FACILITY resource class and protected. UPDATE access to the System level symbolic resources are limited to System Programmers, DASD Administrators, and/or Tape Library personnel. All access is logged. Ensure the guidelines for the resources and/or generic equivalent are followed. Limit access to the IEASYMUP resources to the above personnel with LOG and SERVICE(UPDATE) and/or greater access. The following commands are provided as a sample for implementing resource controls: $KEY(IEASYMUP) TYPE(FAC) - UID(<dasd>) SERVICE(UPDATE) LOG - UID(<sysprgmr>) SERVICE(UPDATE) LOG - UID(<tape librarian>) SERVICE(UPDATE) LOG - UID(*) PREVENT SET R(FAC) COMPILE 'ACF2.FAC(IEASYMUP)' STORE F ACF2,REBUILD(FAC)
Rating Info
DISA Cat II. NIST impact 3.
Expert Comment
None
ACF2-US-000180: IBM z/OS UNIX security parameters for restricted network service(s) in /etc/inetd.conf must be properly specified.
From the UNIX System Services ISPF Shell enter: /etc/inetd.conf If any Restricted Network Services that are listed below are specified or not commented out unless justified and documented with the ISSO, this is a finding. RESTRICTED NETWORK SERVICES/PORTS Service Port Chargen 19 Daytime 13 Discard 9 Echo 7 Exec 512 finger 79 shell 514 time 37 login 513 smtp 25 timed 525 nameserver 42 systat 11 uucp 540 netstat 15 talk 517 qotd 17 tftp 69
Discussion
In order to prevent unauthorized connection of devices, unauthorized transfer of information, or unauthorized tunneling (i.e., embedding of data types within data types), organizations must disable or restrict unused or unnecessary physical and logical ports/protocols on information systems. Operating systems are capable of providing a wide variety of functions and services. Some of the functions and services provided by default may not be necessary to support essential organizational operations. Additionally, it is sometimes convenient to provide multiple services from a single component (e.g., VPN and IPS); however, doing so increases risk over limiting the services provided by any one component. To support the requirements and principles of least functionality, the operating system must support the organizational requirements, providing only essential capabilities and limiting the use of ports, protocols, and/or services to only those required, authorized, and approved to conduct official business or to address authorized quality of life issues.
Fix
Review the settings in The /etc/inetd.conf file determine if every entry in the file represents a service that is actually in use. Services that are not in use must be disabled to reduce potential security exposures. The following services must be disabled in /etc/inetd.conf unless justified and documented with the ISSO: RESTRICTED NETWORK SERVICES Service Port Chargen 19 Daytime 13 Discard 9 Echo 7 Exec 512 finger 79 shell 514 time 37 login 513 smtp 25 timed 525 nameserver 42 systat 11 uucp 540 netstat 15 talk 517 qotd 17 tftp 69 /etc/inetd.conf The /etc/inetd.conf file is used by the INETD daemon. It specifies how INETD is to handle service requests on network sockets. Specifically, there is one entry in inetd.conf for each service. Each service entry specifies several parameters. The login_name parameter is of special interest. It specifies the userid under which the forked daemon is to execute. This userid is defined to the ESM and it may require a UID(0) (i.e., superuser authority) value.
Rating Info
DISA Cat II. NIST impact 3.
Expert Comment
None
ACF2-SM-000060: IBM z/OS using DFSMS must properly specify SYS(x).PARMLIB(IGDSMSxx), SMS parameter settings.
Review the logical parmlib data sets, example: SYS1.PARMLIB(IGDSMSxx), for the following SMS parameter settings: Parameter Key SMS ACDS(ACDS data set name) COMMDS(COMMDS data set name) If the required parameters are defined, this is not a finding.
Discussion
Configuring the operating system to implement organization-wide security implementation guides and security checklists ensures compliance with federal standards and establishes a common security baseline across DoD that reflects the most restrictive security posture consistent with operational requirements. Configuration settings are the set of parameters that can be changed in hardware, software, or firmware components of the system that affect the security posture and/or functionality of the system. Security-related parameters are those parameters impacting the security state of the system, including the parameters required to satisfy other security control requirements. Security-related parameters include, for example: registry settings; account, file, directory permission settings; and settings for functions, ports, protocols, services, and remote connections.
Fix
Configure the DFSMS-related PDS members and statements specified in the system parmlib concatenation as outlined below: Parameter Key SMS ACDS(ACDS data set name) COMMDS(COMMDS data set name)
Rating Info
DISA Cat II. NIST impact 3.
Expert Comment
None
ACF2-ES-000590: CA-ACF2 must prevent the use of dictionary words for passwords.
From the ISPF Command Shell enter: ACF to enter ACF2 Command shell enter SHOW STATE If "PSWDRSV = NO", this is a finding. If "PSWDRSVW = NO", this is a finding. SHOW PSwdopts Reserved Words and Prefixes APPL APR ASDF AUG BASIC CADAM DEC DEMO FEB FOCUS GAME IBM JAN JUL JUN LOG MAR MAY NET NEW NOV OCT PASS ROS SEP SIGN SYS TEST TSO VALID VTAM XXX 1234
Discussion
If the operating system allows the user to select passwords based on dictionary words, then this increases the chances of password compromise by increasing the opportunity for successful guesses and brute-force attacks.
Fix
Configure the GSO record to include PSWDRSV and PSWDRSVW.
Rating Info
DISA Cat II. NIST impact 3.
Expert Comment
None
ACF2-VT-000010: IBM z/OS System data sets used to support the VTAM network must be properly secured.
Create a list of data set names containing all VTAM start options, configuration lists, network resource definitions, commands, procedures, exit routines, all SMP/E TLIBs, and all SMP/E DLIBs used for installation and in development/production VTAM environments. If ACF2 data set rules for all VTAM system data sets do not restrict access to only network systems programming staff, this is a finding. If ACF2 data set rules for all VTAM system data sets do not restrict auditors to READ access only, this is a finding. These data sets include libraries containing VTAM load modules and exit routines, and VTAM start options and definition statements.
Discussion
To mitigate the risk of unauthorized access to sensitive information by entities that have been issued certificates by DoD-approved PKIs, all DoD systems (e.g., web servers and web portals) must be properly configured to incorporate access control methods that do not rely solely on the possession of a certificate for access. Successful authentication must not automatically give an entity access to an asset or security boundary. Authorization procedures and controls must be implemented to ensure each authenticated entity also has a validated and current authorization. Authorization is the process of determining whether an entity, once authenticated, is permitted to access a specific asset. Information systems use access control policies and enforcement mechanisms to implement this requirement. Access control policies include: identity-based policies, role-based policies, and attribute-based policies. Access enforcement mechanisms include: access control lists, access control matrices, and cryptography. These policies and mechanisms must be employed by the application to control access between users (or processes acting on behalf of users) and objects (e.g., devices, files, records, processes, programs, and domains) in the information system. If the operating system were to allow any user to make changes to software libraries, then those changes might be implemented without undergoing the appropriate testing and approvals that are part of a robust change management process. Satisfies: SRG-OS-000080-GPOS-00048, SRG-OS-000259-GPOS-00100
Fix
Define ACF2 data set rules for all VTAM system data sets to restrict access to only network systems programming staff. Auditors may have READ access as documented and approved by ISSM. These data sets include libraries containing VTAM load modules and exit routines, and VTAM start options and definition statements. Example: $KEY(SYS1) VTAM-.- UID(sysprgmr) R(A) W(L) A(L) E(A) $KEY(S3V) $PREFIX(SYS3) VTAM-.- UID(sysprgmr) R(A) W(L) A(L) E(A)
Rating Info
DISA Cat II. NIST impact 3.
Expert Comment
None
ACF2-ES-000730: IBM z/OS must properly protect MCS console userid(s).
Refer to IEASYS00 to determine the correct CONSOLxx member. Examine the CONSOLxx member. Verify that the MCS console logonids are properly restricted. If the following guidance is true, this is not a finding. Each console defined in the currently active CONSOLxx parmlib member is associated with a valid ACF2 logonid. Each console logonid has no special privileges and/or attributes (e.g., ACCOUNT, SECURITY, etc.). Each console logonid has no accesses to interactive online facilities (e.g., TSO, CICS, etc., excluding VTAM SMCS consoles). Each console logonid will be restricted from accessing all data sets and resources except MVS.MCSOPER.consolename in the OPERCMDS resource class and consolename in the CONSOLE resource class. NOTE: If LOGON(AUTO) is specified in the currently active CONSOLxx parmlib member, additional access may be required. Permissions for the console logonids may be given with SERVICE(READ) to MVS.CONTROL, MVS.DISPLAY, MVS.MONITOR, and MVS.STOPMN OPERCMDS resources. NOTE: Execute the JCL in CNTL(ACFRPTRX) using the ACF2 console userids in the LID statements in the SYSIN input. This report lists all occurrences of these userids within the ACF2 database, including data set and resource access lists.
Discussion
In order to prevent unauthorized connection of devices, unauthorized transfer of information, or unauthorized tunneling (i.e., embedding of data types within data types), organizations must disable or restrict unused or unnecessary physical and logical ports/protocols on information systems. Operating systems are capable of providing a wide variety of functions and services. Some of the functions and services provided by default may not be necessary to support essential organizational operations. Additionally, it is sometimes convenient to provide multiple services from a single component (e.g., VPN and IPS); however, doing so increases risk over limiting the services provided by any one component. To support the requirements and principles of least functionality, the operating system must support the organizational requirements, providing only essential capabilities and limiting the use of ports, protocols, and/or services to only those required, authorized, and approved to conduct official business or to address authorized quality of life issues.
Fix
Define all consoles identified in the currently active CONSOLxx parmlib member in EXAM.RPT(PARMLIB) to be defined to the ESM. Review the MCS console resources defined to z/OS and the ESM and ensure they conform to those outlined below. Each console defined in the currently active CONSOLxx parmlib member is associated with a valid ACF2 logonid. Each console logonid has no special privileges and/or attributes (e.g., ACCOUNT, SECURITY, etc., excluding VTAM SMCS consoles). Each console logonid has no accesses to interactive online facilities (e.g., TSO, CICS, etc.). Each console logonid will be restricted from accessing all data sets and resources except MVS.MCSOPER.consolename in the OPERCMDS resource class and consolename in the CONSOLE resource class. NOTE: If LOGON(AUTO) is specified in the currently active CONSOLxx parmlib member, additional access may be required. Permissions for the console logonids may be given with SERVICE(READ) to MVS.CONTROL, MVS.DISPLAY, MVS.MONITOR, and MVS.STOPMN OPERCMDS resources. NOTE: If LOGON(AUTO) is specified in the currently active CONSOLxx parmlib member, additional access may be required. Permissions for the console logonids may be given with SERVICE(READ) to MVS.CONTROL, MVS.DISPLAY, MVS.MONITOR, and MVS.STOPMN OPERCMDS resources. Example: INSERT MVAC20 NAME(MVA CONSOLE C20) PASSWORD(xxxxxxxx) $KEY(MVS) TYPE(OPR) MCSOPER.- UID(MVAC20) SERVICE(READ) ALLOW CONTROL.- UID(MVAC20) SERVICE(READ) ALLOW DATA(FOR LOGON(AUTO)) MONITOR.- UID(MVAC20) SERVICE(READ) ALLOW DATA(FOR LOGON(AUTO)) STOPMN.- UID(MVAC20) SERVICE(READ) ALLOW DATA(FOR LOGON(AUTO)) DISPLAY.- UID(*) SERVICE(READ) ALLOW - UID(*) PREVENT SET R(OPR) COMPILE ' ACF2.MVA.OPR(MVS)' STORE F ACF2,REBUILD(OPR) $KEY(consname) TYPE(CON) UID(MVAC20) SERVICE(READ) ALLOW SET R(CON) COMPILE ' ACF2.MVA.CON(consname)' STORE F ACF2,REBUILD(CON)
Rating Info
DISA Cat II. NIST impact 3.
Expert Comment
None
ACF2-FT-000110: IBM z/OS FTP.DATA configuration for the FTP Server must have INACTIVE statement properly set.
Refer to the Data configuration file specified on the SYSFTPD DD statement in the FTP started task JCL. If the INACTIVE statement is coded with a value between 1 and 900 (seconds) this is not a finding.
Discussion
Terminating an idle session within a short time period reduces the window of opportunity for unauthorized personnel to take control of a management session enabled on the console or console port that has been left unattended. In addition, quickly terminating an idle session will also free up resources committed by the managed network element. Terminating network connections associated with communications sessions includes, for example, de-allocating associated TCP/IP address/port pairs at the operating system level, and de-allocating networking assignments at the application level if multiple application sessions are using a single operating system-level network connection. This does not mean that the operating system terminates all sessions or network access; it only ends the inactive session and releases the resources associated with that session.
Fix
Configure the FTP.DATA CONFIGURATION STATEMENT to include the following: INACTIVE [A value between 1 and 900]
Rating Info
DISA Cat II. NIST impact 3.
Expert Comment
None
ACF2-OS-000130: IBM z/OS BUFUSEWARN in the SMFPRMxx must be properly set.
Refer to IEASYS00 member in SYS1.PARMLIB Concatenation. Determine proper SMFPRMxx member in SYS1.PARMLIB. If BUFUSEWARN is set for 75 (75%) or less this is not a finding.
Discussion
It is critical for the appropriate personnel to be aware if a system is at risk of failing to process audit logs as required. Without this notification, the security personnel may be unaware of an impending failure of the audit capability, and system operation may be adversely affected. Audit processing failures include software/hardware errors, failures in the audit capturing mechanisms, and audit storage capacity being reached or exceeded. This requirement applies to each audit data storage repository (i.e., distinct information system component where audit records are stored), the centralized audit storage capacity of organizations (i.e., all audit data storage repositories combined), or both. Satisfies: SRG-OS-000046-GPOS-00022, SRG-OS-000343-GPOS-00134, SRG-OS-000344-GPOS-00135
Fix
Configure the BUFUSEWARN statement in SMFPRMxx to 75 (75%) or less.
Rating Info
DISA Cat II. NIST impact 3.
Expert Comment
None
ACF2-JS-000030: IBM z/OS JESNEWS resources must be protected in accordance with security requirements.
From the ACF command screen enter: SET RESOURCE(OPR) LIST LIKE(JES-) If the JES2.UPDATE.JESNEWS resource is defined to the OPERCMDS resource class with a default access of PREVENT, this is not a finding. NOTE: JES2 is typically the name of the JES2 subsystem. Refer to the SUBSYS report and locate the entry with the description of PRIMARY JOB ENTRY SUBSYSTEM. The SUBSYSTEM NAME of this entry is the name of the JES2 subsystem. If access authorization to the JES2.UPDATE.JESNEWS resource in the OPERCMDS class restricts DELETE service to the appropriate personnel (i.e., users responsible for maintaining the JES News data set) and all access is logged, this is not a finding.
Discussion
To mitigate the risk of unauthorized access to sensitive information by entities that have been issued certificates by DoD-approved PKIs, all DoD systems (e.g., web servers and web portals) must be properly configured to incorporate access control methods that do not rely solely on the possession of a certificate for access. Successful authentication must not automatically give an entity access to an asset or security boundary. Authorization procedures and controls must be implemented to ensure each authenticated entity also has a validated and current authorization. Authorization is the process of determining whether an entity, once authenticated, is permitted to access a specific asset. Information systems use access control policies and enforcement mechanisms to implement this requirement. Access control policies include: identity-based policies, role-based policies, and attribute-based policies. Access enforcement mechanisms include: access control lists, access control matrices, and cryptography. These policies and mechanisms must be employed by the application to control access between users (or processes acting on behalf of users) and objects (e.g., devices, files, records, processes, programs, and domains) in the information system.
Fix
Configure the resource rules for the OPERCMDS resource class (i.e., TYPE(OPR)) and ensure the following items are in effect: 1) The JES2.UPDATE.JESNEWS resource is defined to the OPERCMDS resource class with a default access of PREVENT. 2) Access authorization to the JES2.UPDATE.JESNEWS resource in the OPERCMDS class restricts DELETE service to the appropriate personnel (i.e., users responsible for maintaining the JES News data set) and all access is logged. Example: $KEY(JES2) TYPE(OPR) UPDATE.JESNEWS UID(SYSPROG) SERVICE(READ,UPDATE) LOG UPDATE.JESNEWS UID(*) PREVENT
Rating Info
DISA Cat II. NIST impact 3.
Expert Comment
None
ACF2-ES-000890: ACF2 PSWD GSO record value must be set to require a 60-day maximum password lifetime restriction.
From an ACF command screen enter: SET CONTROL(GSO) LIST PSWD If "PSWDMAX" is set to "60", this is not a finding.
Discussion
Any password, no matter how complex, can eventually be cracked. Therefore, passwords need to be changed periodically. If the operating system does not limit the lifetime of passwords and force users to change their passwords, there is the risk that the operating system passwords could be compromised.
Fix
Configure Password option "PSWDMAX" to "60" days.
Rating Info
DISA Cat II. NIST impact 3.
Expert Comment
None
ACF2-SM-000040: IBM z/OS DFMSM resource class(es)must be defined to the GSO SAFDEF record in accordance with security requirements.
From the ISPF Command Shell enter: ACF SET CONTROL(GSO) SHOW SAFDEF If both FACILITY and PROGRAM resource classes are defined, this is not a finding.
Discussion
To mitigate the risk of unauthorized access to sensitive information by entities that have been issued certificates by DoD-approved PKIs, all DoD systems (e.g., web servers and web portals) must be properly configured to incorporate access control methods that do not rely solely on the possession of a certificate for access. Successful authentication must not automatically give an entity access to an asset or security boundary. Authorization procedures and controls must be implemented to ensure each authenticated entity also has a validated and current authorization. Authorization is the process of determining whether an entity, once authenticated, is permitted to access a specific asset. Information systems use access control policies and enforcement mechanisms to implement this requirement. Access control policies include: identity-based policies, role-based policies, and attribute-based policies. Access enforcement mechanisms include: access control lists, access control matrices, and cryptography. These policies and mechanisms must be employed by the application to control access between users (or processes acting on behalf of users) and objects (e.g., devices, files, records, processes, programs, and domains) in the information system.
Fix
Define the GSO SAFDEF record with the following definitions: FACILITY PROGRAM Ensure both resource classes above are defined. Example: SHOW SAFDEF SET C(GSO) INSERT SAFDEF.FAC FUNCRET(4) FUNCRSN(0) ID(FACILITY) MODE(GLOBAL) RACROUTE(REQUEST=AUTH CLASS=FACILITY) RETCODE(4) F ACF2,REFRESH(ALL)
Rating Info
DISA Cat II. NIST impact 3.
Expert Comment
None
ACF2-ES-000920: ACF2 TSOTWX GSO record values must be set to obliterate the logon password on TWX devices.
From the ISPF Command Shell enter: ACF <enter> SET CONTROL(GSO) LIST TSOTWX If the GSO TSOTWX record values conform to the following requirements, this is not a finding. CR(15) IDLE(17) LENGTH(8) M1(X) M2(N) M3(Z) M4(M) STRING()
Discussion
To prevent the compromise of authentication information, such as passwords during the authentication process, the feedback from the operating system must not provide any information allowing an unauthorized user to compromise the authentication mechanism. Obfuscation of user-provided information that is typed into the system is a method used when addressing this risk. Displaying asterisks when a user types in a password is an example of obscuring feedback of authentication information.
Fix
Define a cross out mask to obliterate the logon password on TWX devices. CR(15) IDLE(17) LENGTH(8) M1(X) M2(N) M3(Z) M4(M) STRING() Example: SET C(GSO) INSERT TSOTWX CR(15) IDLE(17) LENGTH(8) M1(X) M2(N) M3(Z) M4(M) STRING() F ACF2,REFRESH(TSOTWX)
Rating Info
DISA Cat II. NIST impact 3.
Expert Comment
None
ACF2-OS-002420: IBM z/OS system administrator must develop a procedure to remove all software components after updated versions have been installed.
Ask the system administrator for the procedure to remove all software components after updated versions have been installed. If there is no procedure, this is a finding.
Discussion
Previous versions of software components that are not removed from the information system after updates have been installed may be exploited by adversaries. Some information technology products may remove older versions of software automatically from the information system.
Fix
Develop a procedure to remove all software components after updated versions have been installed.
Rating Info
DISA Cat II. NIST impact 3.
Expert Comment
None
ACF2-ES-000350: CA-ACF2 LOGONIDs must not be defined to SYS1.UADS for non-emergency use.
Ask the system administrator to provide a list of all emergency userids available to the site along with the associated function of each. If SYS1.UADS userids are limited and reserved for emergency purposes only, this is not a finding.
Discussion
Preventing non-privileged users from executing privileged functions mitigates the risk that unauthorized individuals or processes may gain unnecessary access to information or privileges. Privileged functions include, for example, establishing accounts, performing system integrity checks, or administering cryptographic key management activities. Non-privileged users are individuals that do not possess appropriate authorizations. Circumventing intrusion detection and prevention mechanisms or malicious code protection mechanisms are examples of privileged functions that require protection from non-privileged users.
Fix
Configure the SYS1.UADS entries to ensure LOGONIDs defined include only those users required to support specific functions related to system recovery. Evaluate the impact of accomplishing the change.
Rating Info
DISA Cat I. NIST impact 4.
Expert Comment
None
ACF2-TC-000070: IBM z/OS Started tasks for the Base TCP/IP component must be defined in accordance with security requirements.
Verify Logonid(s) assigned to the TCP/IP address space(s), are named TCPIP or, in the case of multiple instances, are prefixed with TCPIP. From an ACF Command screen enter: SET LID LIST LIKE(TCPIP-) If each TCP/IP logonid its defined with STC, MUSASS, and NO-SMC attributes, this is not a finding. From the ACF Command screen enter: SET LID LIST LIKE(TCPIP-) PROFILE(OMVS) If the z/OS UNIX attributes are UID(0), HOME directory '/', shell program /bin/sh, this is not a finding. From an ACF Command screen enter: SET LID LIST EZAZSSI If THE EZAZSSI logonid is defined with STC attribute, this is not a finding. From the ACF Command screen enter: SET LID LIST EZAZSSI PROFILE(OMVS) If the z/OS UNIX attributes are UID(0), HOME directory '/', shell program /bin/sh, this is not a finding.
Discussion
To assure accountability and prevent unauthenticated access, organizational users must be identified and authenticated to prevent potential misuse and compromise of the system. Organizational users include organizational employees or individuals the organization deems to have equivalent status of employees (e.g., contractors). Organizational users (and processes acting on behalf of users) must be uniquely identified and authenticated to all accesses, except for the following: 1) Accesses explicitly identified and documented by the organization. Organizations document specific user actions that can be performed on the information system without identification or authentication; and 2) Accesses that occur through authorized use of group authenticators without individual authentication. Organizations may require unique identification of individuals in group accounts (e.g., shared privilege accounts) or for detailed accountability of individual activity.
Fix
Define the Started tasks for the Base TCP/IP component user accounts with the following characteristics: Named TCPIP or, in the case of multiple instances, prefixed with TCPIP Defined with the STC, MUSASS, and NO-SMC attributes z/OS UNIX attributes: UID(0), HOME directory '/', shell program /bin/sh Named EZAZSSI Defined with the STC attribute z/OS UNIX attributes: UID(non-zero), HOME directory '/', shell program /bin/sh Review the TCP/IP started task accounts, privileges, and access authorizations defined to the ACP. Ensure they conform to the requirements as outlined below. The following commands can be used to create the user accounts that are required for the TCP/IP address space and the EZAZSSI started task: SET LID INSERT TCPIP NAME(TCPIP) GROUP(STCTCPX) STC MUSASS NO-SMC INSERT EZAZSSI NAME(EZAZSSI) GROUP(STCTCPX) STC SET PROFILE(USER) DIVISION(OMVS) INSERT TCPIP UID(0) HOME(/) OMVSPGM(/bin/sh) INSERT EZAZSSI UID(non-zero) HOME(/) OMVSPGM(/bin/sh) F ACF2,REBUILD(USR),CLASS(P) NOTE: At eTrust CA-ACF2 6.4 and above, the PROGRAM field in the user profile record has been renamed to OMVSPGM. The following additions to the indicated rule sets can be used to assign the privileges that are required for the TCP/IP address space: $KEY(BPX) TYPE(FAC) ... DAEMON UID(TCPIP-uid) SERVICE(READ) ALLOW If the z/OS host machine has hardware encryption installed and enabled, resources owned by the Integrated Cryptographic Service Facility (ICSF) component have been defined. The following rule set additions are required to allow the TN3270 Telnet Server process to access the ICSF resources. - $KEY(CSFCKI) TYPE(CSF) - UID(TCPIP-uid) SERVICE(READ) ALLOW - $KEY(CSFCKM) TYPE(CSF) - UID(TCPIP-uid) SERVICE(READ) ALLOW - $KEY(CSFDEC) TYPE(CSF) - UID(TCPIP-uid) SERVICE(READ) ALLOW - $KEY(CSFENC) TYPE(CSF) - UID(TCPIP-uid) SERVICE(READ) ALLOW - $KEY(CSFOWH) TYPE(CSF) - UID(TCPIP-uid) SERVICE(READ) ALLOW - $KEY(CSFRNG) TYPE(CSF) - UID(TCPIP-uid) SERVICE(READ) ALLOW - $KEY(CSFPKB) TYPE(CSF) - UID(TCPIP-uid) SERVICE(READ) ALLOW - $KEY(CSFPKX) TYPE(CSF) - UID(TCPIP-uid) SERVICE(READ) ALLOW - $KEY(CSFPKE) TYPE(CSF) - UID(TCPIP-uid) SERVICE(READ) ALLOW - $KEY(CSFPKD) TYPE(CSF) - UID(TCPIP-uid) SERVICE(READ) ALLOW - $KEY(CSFPKI) TYPE(CSF) - UID(TCPIP-uid) SERVICE(READ) ALLOW - $KEY(CSFDSG) TYPE(CSF) - UID(TCPIP-uid) SERVICE(READ) ALLOW - $KEY(CSFDSV) TYPE(CSF) - UID(TCPIP-uid) SERVICE(READ) ALLOW The following operator commands are required to complete the updates: F ACF2,REBUILD(FAC) F ACF2,REBUILD(CSF) These commands and definitions assume that the default type code for CSFSERV resources is CSF.
Rating Info
DISA Cat II. NIST impact 3.
Expert Comment
None
ACF2-ES-000840: ACF2 PSWD GSO record value must be set to require at least one uppercase character be used.
From the ISPF Command Shell enter: ACF to enter ACF2 Command shell enter SET CONTROL(GSO) LIST PSWD If NOPSWDUC is listed, this is a finding.
Discussion
Use of a complex password helps to increase the time and resources required to compromise the password. Password complexity, or strength, is a measure of the effectiveness of a password in resisting attempts at guessing and brute-force attacks.
Fix
Configure the GSO option "PSWDUC" to "YES".
Rating Info
DISA Cat II. NIST impact 3.
Expert Comment
None
ACF2-ES-000880: ACF2 must use NIST FIPS-validated cryptography to protect passwords in the security database.
From an ACF command screen enter: SET CONTROL(GSO) LIST PSWD If the "GSO PSWD" record option "PSWDENCT" is set to "XDES" or null, this is a finding. SET MSYSID(-) LIST PSWD For CA-ACF2 R16 and above: If option "NOONEPWALG" is specified, and there is no transition plan with a definite completion date filed with the ISSM, this is a finding.
Discussion
Passwords need to be protected at all times, and encryption is the standard method for protecting passwords. If passwords are not encrypted, they can be plainly read (i.e., clear text) and easily compromised. Satisfies: SRG-OS-000073-GPOS-00041, SRG-OS-000074-GPOS-00042
Fix
Evaluate the impact associated with implementation of the control option. Develop a plan of action to implement the control option as specified below: Configure the "GSO PSWD" record option "PSWDENCT" to "AES1". For CA-ACF2 Release16 and above: Configure "GSO PSWD" record option "PSWDENCT" to "AES1" or "AES2". Configure the "GSO PSWD" to "ONEPWALG". Note: If you are using VM Database Synchronization you cannot use "ONEPWALG". VM does not support the AES algorithms. Develop a transition plan with a definite completion date for z/VM; file with the ISSM. If all systems that are sharing the logonid or infostorage databases are not running with the same "PSWDENCT" value you cannot use "ONEPWALG". Develop a transition plan that contains a definite completion date to migrate all logonid and infostorage databases to one "PSWDENCT" value; file with the ISSM. Consult the CA-ACF2 administration guide for converting to "AES1" or "AES2" and using "ONEPWALG".
Rating Info
DISA Cat I. NIST impact 4.
Expert Comment
None
ACF2-TN-000020: IBM z/OS SMF recording options for the TN3270 Telnet Server must be properly specified.
Refer to the Profile configuration file specified on the PROFILE DD statement in the TCPIP started task JCL. If the following configuration statement settings are in effect in the TCP/IP Profile configuration data set, this is not a finding. NOTE: If the INCLUDE statement is coded in the TCP/IP Profile configuration data set, the data set specified on this statement must be checked for the following items as well. The TELNETPARMS SMFINIT statement is coded with the TYPE119 operand within each TELNETPARMS statement block. The TELNETPARMS SMFTERM statement is coded with the TYPE119 operand within each TELNETPARMS statement block. NOTE: Effective in z/OS release 1.2, the SMFINIT and SMFTERM statement can appear in both TELNETGLOBAL and TELNETPARM statement blocks.
Discussion
If events associated with nonlocal administrative access or diagnostic sessions are not logged, a major tool for assessing and investigating attacks would not be available. This requirement addresses auditing-related issues associated with maintenance tools used specifically for diagnostic and repair actions on organizational information systems. Nonlocal maintenance and diagnostic activities are those activities conducted by individuals communicating through a network, either an external network (e.g., the Internet) or an internal network. Local maintenance and diagnostic activities are those activities carried out by individuals physically present at the information system or information system component and not communicating across a network connection. This requirement applies to hardware/software diagnostic test equipment or tools. This requirement does not cover hardware/software components that may support information system maintenance, yet are a part of the system, for example, the software implementing "ping," "ls," "ipconfig," or the hardware and software implementing the monitoring port of an Ethernet switch. Satisfies: SRG-OS-000392-GPOS-00172, SRG-OS-000032-GPOS-00013
Fix
Configure the TELNETPARMS SMFINIT and SMFTERM statements in the PROFILE.TCPIP file to conform to the requirements specified below. NOTE: If the INCLUDE statement is coded in the TCP/IP Profile configuration file, the data set specified on this statement must be checked for the following items as well. The TELNETPARMS SMFINIT statement is coded with the TYPE119 operand within each TELNETPARMS statement block. The TELNETPARMS SMFTERM statement is coded with the TYPE119 operand within each TELNETPARMS statement block. NOTE: Effective in z/OS release 1.2, the SMFINIT and SMFTERM statement can appear in both TELNETGLOBAL and TELNETPARM statement blocks.
Rating Info
DISA Cat II. NIST impact 3.
Expert Comment
None
ACF2-US-000200: IBM z/OS UNIX user accounts must be properly defined.
From an ACF Command screen enter: SET PROFILE(USER) DIV(OMVS) LI LIKE(-) If each user account is defined as follows, this is not a finding. A unique UID number (except for UID(0) users) Use the following as a quick test for duplicate UIDs apart from UID 0 SHOW OMVS USERS(1-2147483647) DUPLICATES -A unique HOME directory (UID(0), other system task accounts, and tasks approved by the ISSM are excluded from this rule). -Shell program specified as "/bin/sh", "/bin/tcsh", "/bin/echo", or "/bin/false" NOTE: The shell program must have one of the specified values. The HOME directory must have a value (i.e., not be allowed to default; this does not include tasks that are excluded from above).
Discussion
To ensure accountability and prevent unauthenticated access, organizational users must be identified and authenticated to prevent potential misuse and compromise of the system. Organizational users include organizational employees or individuals the organization deems to have equivalent status of employees (e.g., contractors). Organizational users (and processes acting on behalf of users) must be uniquely identified and authenticated to all accesses, except for the following: 1) Accesses explicitly identified and documented by the organization. Organizations document specific user actions that can be performed on the information system without identification or authentication; and 2) Accesses that occur through authorized use of group authenticators without individual authentication. Organizations may require unique identification of individuals in group accounts (e.g., shared privilege accounts) or for detailed accountability of individual activity.
Fix
Define users of z/OS UNIX (i.e., users with an OMVS profile defined) as follows: -A unique UID number (except for UID(0) users). -A unique HOME directory (UID(0), other system task accounts, and tasks approved by the ISSM are excluded from this rule). -Shell program specified as "/bin/sh", "/bin/tcsh", "/bin/echo", or "/bin/false". NOTE: The shell program must have one of the specified values. The HOME directory must have a value (i.e., not be allowed to default; this does not include tasks that are excluded from above).
Rating Info
DISA Cat II. NIST impact 3.
Expert Comment
None
ACF2-ES-000540: IBM z/OS LOGONIDs with the AUDIT or CONSULT attribute must be properly scoped.
From the ACF Command Screen enter: SET LID LIST IF(AUDIT) If all logonids with the attributes AUDIT and/or CONSULT also do not have the SCPLIST attribute specified properly according to job function and areas of responsibility, this is a finding. NOTE: SCPLST attributes are not required for Logonids with the attributes AUDIT or CONSULT if the security ISSM/ISSO determines it requires ability to view the entire ACF2 environment. SCPLST attributes are not required for Auditors, Domain Level Security Admin Logonids, and BATCH Logonids that review the entire ACF2 environment to include GSO records, data set and resource rules, etc. or run audit reports.
Discussion
The use of security policy filters provides protection for the confidentiality of data by restricting the flow of data. A crucial part of any flow control solution is the ability to configure policy filters. This allows the operating system to enforce multiple and different security policies. Policy filters serve to enact and enforce the organizational policy as it pertains to controlling data flow.
Fix
Configure logonids with the AUDIT or CONSULT attributes are restricted by a SCPLIST attribute that restricts authority based on job function and area of responsibility. The following user attributes allow viewing of the ACF2 databases for the purpose of inspecting users, data set access rules, and Infostorage records. When granted to a logonid, restrict the scope of the following attributes using an associated SCPLIST (scope list) record: AUDIT CONSULT NOTE: SCPLST attributes are not required for Logonids with the attributes AUDIT or CONSULT if the security ISSM/ISSO determines it requires ability to view the entire ACF2 environment. SCPLST attributes are not required for Auditors, Domain Level Security Admin Logonids, and BATCH Logonids that review the entire ACF2 environment to include GSO records, data set and resource rules, etc. or run audit reports.
Rating Info
DISA Cat II. NIST impact 3.
Expert Comment
None
ACF2-OS-000150: IBM z/OS SNTP daemon (SNTPD) permission bits must be properly configured.
From the ISPF Command Shell enter: cd /usr/sbin ls -al If the following File permission and user Audit Bits are true, this is not a finding. /usr/sbin/sntpd 1740 faf The following represents a hierarchy for permission bits from least restrictive to most restrictive: 7 rwx (least restrictive) 6 rw- 3 -wx 2 -w- 5 r-x 4 r-- 1 --x 0 --- (most restrictive) The possible audit bits settings are as follows: f log for failed access attempts a log for failed and successful access - no auditing
Discussion
Inaccurate time stamps make it more difficult to correlate events and can lead to an inaccurate analysis. Determining the correct time, a particular event occurred on a system is critical when conducting forensic analysis and investigating system events. Sources outside the configured acceptable allowance (drift) may be inaccurate. Synchronizing internal information system clocks provides uniformity of time stamps for information systems with multiple system clocks and systems connected over a network. Organizations should consider endpoints that may not have regular access to the authoritative time server (e.g., mobile, teleworking, and tactical endpoints).
Fix
With the assistance of a systems programmer with UID(0) and/or SUPERUSER access, configure the UNIX permission bits and user audit bits on the SNTPD to conform to the specifications below: /usr/sbin/sntpd 1740 faf
Rating Info
DISA Cat II. NIST impact 3.
Expert Comment
None
ACF2-FT-000030: IBM z/OS permission bits and user audit bits for HFS objects that are part of the FTP Server component must be properly configured.
From the ISPF Command shell enter: omvs At the input line enter: cd /usr/sbin/ enter ls -alW If the following file permission and user Audit Bits are true, this is not a finding. /usr/sbin/ftpd 1740 fff /usr/sbin/ftpdns 1755 fff /usr/sbin/tftpd 0644 faf cd ls -alW If the following file permission and user Audit Bits are true, this is not a finding. /etc/ftp.data 0744 faf /etc/ftp.banner 0744 faf NOTES: Some of the files listed above are not used in every configuration. The absence of a file is not considered a finding. The /usr/sbin/ftpd and /usr/sbin/ftpdns objects are symbolic links to /usr/lpp/tcpip/sbin/ftpd and /usr/lpp/tcpip/sbin/ftpdns respectively. The permission and user audit bits on the targets of the symbolic links must have the required settings. The /etc/ftp.data file may not be the configuration file the server uses. It is necessary to check the SYSFTPD DD statement in the FTP started task JCL to determine the actual file. The TFTP Server does not perform any user identification or authentication, allowing any client to connect to the TFTP Server. Due to this lack of security, the TFTP Server will not be used. The TFTP Client is not secured from use. The permission bits for /usr/sbin/tftpd should be set to "644". The /etc/ftp.banner file may not be the banner file the server uses. It is necessary to check the BANNER statement in the FTP Data configuration file to determine the actual file. Also, the permission bit setting for this file must be set as indicated in the table above. A more restrictive set of permissions is not permitted. The following represents a hierarchy for permission bits from least restrictive to most restrictive: 7 rwx (least restrictive) 6 rw- 3 -wx 2 -w- 5 r-x 4 r-- 1 --x 0 --- (most restrictive) The possible audit bits settings are as follows: f log for failed access attempts a log for failed and successful access - no auditing
Discussion
MVS data sets of the FTP Server provide the configuration and operational characteristics of this product. Failure to properly secure these data sets may lead to unauthorized access resulting in the compromise of the integrity and availability of customer data and some system services.
Fix
Ensure the UNIX permission bits and user audit bits on the HFS directories and files for the FTP Server conform to the specifications in the table below: FTP Server HFS Object Security Settings File Permission Bits User Audit Bits /usr/sbin/ftpd 1740 fff /usr/sbin/ftpdns 1755 fff /usr/sbin/tftpd 0644 faf /etc/ftp.data 0744 faf /etc/ftp.banner 0744 faf The /usr/sbin/ftpd and /usr/sbin/ftpdns objects are symbolic links to /usr/lpp/tcpip/sbin/ftpd and /usr/lpp/tcpip/sbin/ftpdns respectively. The permission and user audit bits on the targets of the symbolic links must have the required settings. The TFTP Server does not perform any user identification or authentication, allowing any client to connect to the TFTP Server. Due to this lack of security, the TFTP Server will not be used. The TFTP Client is not secured from use. The /etc/ftp.data file may not be the configuration file the server uses. It is necessary to check the SYSFTPD DD statement in the FTP started task JCL to determine the actual file. The /etc/ftp.banner file may not be the banner file the server uses. It is necessary to check the BANNER statement in the FTP Data configuration file to determine the actual file. The following represents a hierarchy for permission bits from least restrictive to most restrictive: 7 rwx (least restrictive) 6 rw- 3 -wx 2 -w- 5 r-x 4 r-- 1 --x 0 --- (most restrictive) The possible audit bits settings are as follows: f log for failed access attempts a log for failed and successful access - no auditing Some of the files listed above (e.g., /etc/ftp.data) are not used in every configuration. While the absence of a file is generally not a security issue, the existence of a file that has not been properly secured can often be an issue. Therefore, all files that do exist should have the specified permission and audit bit settings. The following commands can be used (from a user account with an effective UID(0)) to update the permission bits and audit bits: chmod 1740 /usr/lpp/tcpip/sbin/ftpd chaudit rwx=f /usr/lpp/tcpip/sbin/ftpd chmod 1755 /usr/lpp/tcpip/sbin/ftpdns chaudit rwx=f /usr/lpp/tcpip/sbin/ftpdns chmod 0744 /etc/ftp.data chaudit w=sf,rx+f /etc/ftp.data chmod 0744 /etc/ftp.banner chaudit w=sf,rx+f /etc/ftp.banner
Rating Info
DISA Cat II. NIST impact 3.
Expert Comment
None
ACF2-US-000110: IBM z/OS UNIX MVS data sets used as step libraries in /etc/steplib must be properly protected.
Refer to the STEPLIBLIST statement in the BPXPRMxx member of PARMLIB. If the STEPLIBLIST points to an etc/steplib, go to the ISPF Command Shell and enter: OMVS cd /etc cat <filename> If the ESM data set rules for libraries specified in the STEPLIBLIST file do not restrict WRITE and/or ALLOCATE access to only systems programming personnel, this is a finding. If the ESM data set rules for libraries specified in the STEPLIBLIST file do not specify that all (i.e., failures and successes) WRITE and/or ALLOCATE access will be logged, this is a finding.
Discussion
To mitigate the risk of unauthorized access to sensitive information by entities that have been issued certificates by DoD-approved PKIs, all DoD systems (e.g., web servers and web portals) must be properly configured to incorporate access control methods that do not rely solely on the possession of a certificate for access. Successful authentication must not automatically give an entity access to an asset or security boundary. Authorization procedures and controls must be implemented to ensure each authenticated entity also has a validated and current authorization. Authorization is the process of determining whether an entity, once authenticated, is permitted to access a specific asset. Information systems use access control policies and enforcement mechanisms to implement this requirement. Access control policies include: identity-based policies, role-based policies, and attribute-based policies. Access enforcement mechanisms include: access control lists, access control matrices, and cryptography. These policies and mechanisms must be employed by the application to control access between users (or processes acting on behalf of users) and objects (e.g., devices, files, records, processes, programs, and domains) in the information system. Satisfies: SRG-OS-000080-GPOS-00048, SRG-OS-000259-GPOS-00100, SRG-OS-000324-GPOS-00125
Fix
Define the STEPLIBLIST with update and allocate access to libraries residing in the /etc/steplib limited to systems programmers only. The STEPLIBLIST parameter specifies the pathname of the HFS file that contains the list of MVS data sets used as step libraries for programs that have the set-user-id or set group id permission bit set. The use of STEPLIBLIST is at the site's discretion, but if used, the value of STEPLIBLIST will be /etc/steplib. All WRITE and ALLOCATE access to the MVS data sets in the list will be logged and only systems programming personnel will be authorized to update the data sets.
Rating Info
DISA Cat II. NIST impact 3.
Expert Comment
None
ACF2-US-000050: IBM z/OS UNIX MVS HFS directory(s) with other write permission bit set must be properly defined.
On the OMVS Command line enter the following command string: find / -type d -perm -0002 ! -perm -1000 -exec ls -aldWE {} \; If there are no directories that have the other write permission bit set on without the sticky bit set on, this is not a finding. NOTE: In the symbolic permission bit display, the sticky bit is indicated as a "t" or "T" in the execute portion of the other permissions. For example, a display of the permissions of a directory with the sticky bit on could be "drwxrwxrwt". If all directories that have the other write permission bit set on do not contain any files with the setuid bit set on, this is not a finding. NOTE: In the symbolic permission bit display, the setuid bit is indicated as an "s" or "S" in the execute portion of the owner permissions. For example, a display of the permissions of a file with the setuid bit on could be "-rwsrwxrwx". If all directories that have the other write permission bit set on do not contain any files with the setgid bit set on, this is not a finding. NOTE: In the symbolic permission bit display, the setgid bit is indicated as an "s" or "S" in the execute portion of the group permissions. For example, a display of the permissions of a file with the setgid bit on could be "-rwxrwsrwx".
Discussion
Access control policies include: identity-based policies, role-based policies, and attribute-based policies. Access enforcement mechanisms include: access control lists, access control matrices, and cryptography. These policies and mechanisms must be employed by the application to control access between users (or processes acting on behalf of users) and objects (e.g., devices, files, records, processes, programs, and domains) in the information system.
Fix
Configure directory permissions as follows: There are no directories that have the other Write permission bit set on without the sticky bit set on. NOTE: In the symbolic permission bit display, the sticky bit is indicated as a "t" or "T" in the execute portion of the other permissions. For example, a display of the permissions of a directory with the sticky bit on could be "drwxrwxrwt". All directories that have the other write permission bit set on do not contain any files with the setuid bit set on. NOTE: In the symbolic permission bit display, the setuid bit is indicated as an "s" or "S" in the execute portion of the owner permissions. For example, a display of the permissions of a file with the setuid bit on could be "-rwsrwxrwx". All directories that have the other write permission bit set on do not contain any files with the setgid bit set on. NOTE: In the symbolic permission bit display, the setgid bit is indicated as an "s" or "S" in the execute portion of the group permissions. For example, a display of the permissions of a file with the setgid bit on could be "-rwxrwsrwx".
Rating Info
DISA Cat II. NIST impact 3.
Expert Comment
None
ACF2-OS-002440: IBM z/OS must employ a session manager configured for users to directly initiate a session lock for all connection types.
Ask the system administrator for the configuration parameters for the session manager in use. If there is no session manager in use, this is a finding. If the session manager in use does not allow users to directly initiate a session lock for all connection types, this is a finding.
Discussion
A session lock is a temporary action taken when a user stops work and moves away from the immediate physical vicinity of the information system but does not want to log out because of the temporary nature of the absence. The session lock is implemented at the point where session activity can be determined. Rather than be forced to wait for a period of time to expire before the user session can be locked, operating systems need to provide users with the ability to manually invoke a session lock so users may secure their session should the need arise for them to temporarily vacate the immediate physical vicinity.
Fix
Configure the session manage to allow users to directly initiate a session lock for all connection types.
Rating Info
DISA Cat II. NIST impact 3.
Expert Comment
None
ACF2-FT-000100: IBM z/OS startup parameters for the FTP Server must be defined in the SYSTCPD and SYSFTPD DD statements for configuration files.
Refer to the Profile configuration file specified on the PROFILE DD statement in the TCPIP started task JCL. If all the items below are true, this is not a finding. If any of the items below are untrue, this is a finding. The following items are in effect for the FTP daemon's started task JCL: The SYSTCPD and SYSFTPD DD statements specify the TCP/IP Data and FTP Data configuration files respectively. The ANONYMOUS keyword is not coded on the PARM parameter on the EXEC statement. The ANONYMOUS=logonid combination is not coded on the PARM parameter on the EXEC statement. The INACTIVE keyword is not coded on the PARM parameter on the EXEC statement. The AUTOLOG statement block can be configured to have TCP/IP start the FTP Server. The FTP entry (e.g., FTPD) can include the PARMSTRING parameter to pass parameters to the FTP procedure when started. NOTE: Parameters passed on the PARMSTRING parameter override parameters specified in the FTP procedure. If an FTP entry is configured in the AUTOLOG statement block in the TCP/IP Profile configuration file, ensure the following items are in effect: The ANONYMOUS keyword is not coded on the PARMSTRING parameter. The ANONYMOUS=logonid combination is not coded on the PARMSTRING parameter. The INACTIVE keyword is not coded on PARMSTRING parameter.
Discussion
Terminating an idle session within a short time period reduces the window of opportunity for unauthorized personnel to take control of a management session enabled on the console or console port that has been left unattended. In addition, quickly terminating an idle session will also free up resources committed by the managed network element. Terminating network connections associated with communications sessions includes, for example, de-allocating associated TCP/IP address/port pairs at the operating system level, and de-allocating networking assignments at the application level if multiple application sessions are using a single operating system-level network connection. This does not mean that the operating system terminates all sessions or network access; it only ends the inactive session and releases the resources associated with that session.
Fix
Review the FTP daemon's started task JCL. Ensure that the ANONYMOUS and INACTIVE startup parameters are not specified and configuration file names are specified on the appropriate DD statements. The FTP daemon program can accept parameters in the JCL procedure that is used to start the daemon. The ANONYMOUS and ANONYMOUS= keywords are designed to allow anonymous FTP connections. The INACTIVE keyword is designed to set the timeout value for inactive connections. Control of these options is recommended through the configuration file statements rather than the startup parameters. The systems programmer responsible for supporting ICS will ensure that the startup parameters for the FTP daemon does not include the ANONYMOUS, ANONYMOUS=, or INACTIVE keywords. During initialization the FTP daemon searches multiple locations for the TCPIP.DATA and FTP.DATA files according to fixed sequences. In the daemon's started task JCL, Data Definition (DD) statements will be used to specify the locations of the files. The SYSTCPD DD statement identifies the TCPIP.DATA file and the SYSFTPD DD statement identifies the FTP.DATA file. The systems programmer responsible for supporting ICS will ensure that the FTP daemon's started task JCL specifies the SYSTCPD and SYSFTPD DD statements for configuration files.
Rating Info
DISA Cat II. NIST impact 3.
Expert Comment
None
ACF2-ES-000010: CA-ACF2 OPTS GSO record must be set to ABORT mode.
From the ISPF Command Shell enter "ACF" to enter ACF2 Command shell. Enter "SHOW STATE". If the "GSO OPTS" record show a "MODE= ABORT", this is not a finding.
Discussion
Enterprise environments make account management challenging and complex. A manual process for account management functions adds the risk of a potential oversight or other errors. A comprehensive account management process that includes automation helps to ensure accounts designated as requiring attention are consistently and promptly addressed. Examples include, but are not limited to, using automation to take action on multiple accounts designated as inactive, suspended, or terminated, or by disabling accounts located in non-centralized account stores such as multiple servers. This requirement applies to all account types, including individual/user, shared, group, system, guest/anonymous, emergency, developer/manufacturer/vendor, temporary, and service. The automated mechanisms may reside within the operating system itself or may be offered by other infrastructure providing automated account management capabilities. Automated mechanisms may be composed of differing technologies that, when placed together, contain an overall automated mechanism supporting an organization's automated account management requirements. Account management functions include: assigning group or role membership; identifying account type; specifying user access authorizations (i.e., privileges); account removal, update, or termination; and administrative alerts. The use of automated mechanisms can include, for example: using email or text messaging to automatically notify account managers when users are terminated or transferred; using the information system to monitor account usage; and using automated telephonic notification to report atypical system account usage. Satisfies: SRG-OS-000001-GPOS-00001, SRG-OS-000480-GPOS-00229
Fix
Configure the GSO Option for "MODE" to equal "ABORT".
Rating Info
DISA Cat I. NIST impact 4.
Expert Comment
None
ACF2-ES-000600: CA-ACF2 database must be on a separate physical volume from its backup and recovery data sets.
From the ACF Command screen, enter: SET CONTROL(GSO) SHOW DDSN Exexute the ISPF Data Set List Utility for each dataset listed to determine the volume. If the ACF2 database is not located on the same volume as either its alternate or backup file, this is not a finding. If the ACF2 database is collocated with either its alternate or backup, this is a finding.
Discussion
Configuring the operating system to implement organization-wide security implementation guides and security checklists ensures compliance with federal standards and establishes a common security baseline across DoD that reflects the most restrictive security posture consistent with operational requirements.
Fix
Configure the placement of ACF2 files are on a separate volume from its backup and recovery data sets to provide backup and recovery in the event of physical damage to a volume. Identify the ACF2 database(s), backup database(s), and recovery data set(s). Develop a plan to keep these data sets on different physical volumes. Implement the movement of these critical ACF2 files. File location is an often overlooked factor in system integrity. It is important to ensure that the effects of hardware failures on system integrity and availability are minimized. Avoid collocation of files such as primary and alternate databases. For example, the loss of the physical volume containing the ACF2 database should not also cause the loss of the ACF2 backup database as a result of their collocation. Files that will be segregated from each other on separate physical volumes include, but are not limited to, the ACF2 database and its alternate or backup file.
Rating Info
DISA Cat II. NIST impact 3.
Expert Comment
None
ACF2-ES-000490: The EXITS GSO record value must specify the module names of site written ACF2 exit routines.
From the ACF Command enter: SET CONTROL(GSO) LIST LIKE(EXIT-) If the GSO EXITS record values conform to the following requirements, this is not a finding. Specifies the module names of site written ACF2 exit routines. NOTE: The DSNPOST exit is optional and is not required to be specified in the GSO EXITS record. DSNPOST(module) SEVPRE(SEVPRE01) SEVPOST(SEVPST01) NOTE: No other exits are authorized at this time. NOTE: Local changes will be documented in writing with supporting documentation. If there is any deviation from the above requirements in the GSO EXITS record values, this is a finding.
Discussion
Configuring the operating system to implement organization-wide security implementation guides and security checklists ensures compliance with federal standards and establishes a common security baseline across DoD that reflects the most restrictive security posture consistent with operational requirements.
Fix
Configure the EXITS GSO value to specify the module names of site written ACF2 exit routines. Specifies the module names of site written ACF2 exit routines. NOTE: The DSNPOST exit is optional and is not required to be specified in the GSO EXITS record. DSNPOST(module) SEVPRE(SEVPRE01) SEVPOST(SEVPST01) Example: SET C(GSO) INSERT EXITS DSNPOST(module) SEVPRE(SEVPRE01) SEVPOST(SEVPST01) F ACF2,REFRESH(EXITS) NOTE: No other exits are authorized at this time. NOTE: Local changes will be justified in writing with supporting documentation.
Rating Info
DISA Cat II. NIST impact 3.
Expert Comment
None
ACF2-OS-000100: IBM z/OS must specify SMF data options to assure appropriate activation.
Refer to IEASYS00 member in SYS1.PARMLIB Concatenation. Determine proper SMFPRMxx member. If the following SMF collection options are specified as stated below, this is not a finding. The settings for several parameters are critical to the collection process: ACTIVE - Activates the collection of SMF data. MAXDORM - Specifies the amount of real time that SMF allows data to remain in an SMF buffer before it is written to a recording data set. Value is site defined. SID - Specifies the system ID to be recorded in all SMF records. SYS(DETAIL) - Controls the level of detail recorded. SYS(INTERVAL) - Ensures the periodic recording of data for long running jobs. SYS - Specifies the types and sub types of SMF records that are to be collected. SYS(TYPE) indicates that the supplied list is inclusive (i.e., specifies the record types to be collected). Record types not listed are not collected. SYS(NOTYPE) indicates that the supplied list is exclusive (i.e., specifies those record types not to be collected). Record types listed are not collected. The site may use either form of this parameter to specify SMF record type collection. However, at a minimum all record types listed.
Discussion
Without establishing when events occurred, it is impossible to establish, correlate, and investigate the events leading up to an outage or attack. In order to compile an accurate risk assessment and provide forensic analysis, it is essential for security personnel to know when events occurred (date and time). Associating event types with detected events in the operating system audit logs provides a means of investigating an attack; recognizing resource utilization or capacity thresholds; or identifying an improperly configured operating system. SMF data collection is the basic unit of tracking of all system functions and actions. Included in this tracking data are the audit trails from each of the ACPs. If the control options for the recording of this tracking are not properly maintained, then accountability cannot be monitored, and its use in the execution of a contingency plan could be compromised. Satisfies: SRG-OS-000038-GPOS-00016, SRG-OS-000039-GPOS-00017, SRG-OS-000040-GPOS-00018, SRG-OS-000041-GPOS-00019, SRG-OS-000042-GPOS-00021, SRG-OS-000254-GPOS-00095, SRG-OS-000269-GPOS-00103
Fix
Ensure that collection options for SMF Data are consistent with options specified below. Review all SMF recording specifications found in SMFPRMxx members. Ensure that SMF recording options used are consistent with those outlined below. The settings for several parameters are critical to the collection process: ACTIVE Activates the collection of SMF data. MAXDORM(mmss) Specifies the amount of real time that SMF allows data to remain in an SMF buffer before it is written to a recording data set. Use the MAXDORM parameter to minimize the amount of data lost because of system failure. This value is site determined and should be carefully configured. SID Specifies the system ID to be recorded in all SMF records. SYS(DETAIL) Controls the level of detail recorded. SYS(INTERVAL) Ensures the periodic recording of data for long running jobs. SYS Specifies the types and sub types of SMF records that are to be collected. SYS(TYPE) indicates that the supplied list is inclusive (i.e., specifies the record types to be collected). Record types not listed are not collected. SYS(NOTYPE) indicates that the supplied list is exclusive (i.e., specifies those record types not to be collected). Record types not listed are not collected. The site may use either form of this parameter to specify SMF record type collection. However, at a minimum all record types listed.
Rating Info
DISA Cat II. NIST impact 3.
Expert Comment
None
ACF2-TC-000030: IBM z/OS TCP/IP resources must be properly protected.
From the ACF command screen enter: SET RESOURCE(SER) SET VERBOSE The SERVAUTH resource class is mapped to the standard resource type SER. LIST LIKE (-) If no access is given to the EZA, EZB, and IST high level resources of the SERVAUTH resource class, and default access of PREVENT is specified, this is not a finding. If the product CSSMTP is on the system, no access is given to EZB.CSSMTP of the SERVAUTH resource class, this is not a finding. If the product CSSMTP is on the system, EZB.CSSMTP.sysname.writername.JESnode will be specified and made available to the CSSMTP started task and authenticated users that require access to use CSSMTP for email services. Authenticated users that require access will be permitted access to the second level of the resources in the SERVAUTH resource class. Examples are the network (NETACCESS), port (PORTACCESS), stack (STACKACCESS), and FTP resources in the SERVAUTH resource class. If the EZB.STACKACCESS. resource access authorizations restrict access to those started tasks with valid requirements and users with valid FTP access requirements, this is not a finding. If the EZB.FTP.*.*.ACCESS.HFS resource access authorizations restrict access to FTP users with specific written documentation showing a valid requirement exists to access OMVS files and Directories, this is not a finding. If the EZB.INITSTACK.sysname.tcpname resource access authorizations restrict access before policies have been installed, to users authorized by the system security plan requiring access to the TCP/IP stack, this is not a finding.
Discussion
To mitigate the risk of unauthorized access to sensitive information by entities that have been issued certificates by DoD-approved PKIs, all DoD systems (e.g., web servers and web portals) must be properly configured to incorporate access control methods that do not rely solely on the possession of a certificate for access. Successful authentication must not automatically give an entity access to an asset or security boundary. Authorization procedures and controls must be implemented to ensure each authenticated entity also has a validated and current authorization. Authorization is the process of determining whether an entity, once authenticated, is permitted to access a specific asset. Information systems use access control policies and enforcement mechanisms to implement this requirement. Access control policies include: identity-based policies, role-based policies, and attribute-based policies. Access enforcement mechanisms include: access control lists, access control matrices, and cryptography. These policies and mechanisms must be employed by the application to control access between users (or processes acting on behalf of users) and objects (e.g., devices, files, records, processes, programs, and domains) in the information system.
Fix
Develop a plan of action to implement the required changes. Ensure the following items are in effect for TCP/IP resources. (Note: The resource class, resources, and/or resource prefixes identified below are examples of a possible installation. The actual resource class, resources, and/or resource prefixes are determined when the product is actually installed on a system through the product's installation guide and can be site specific.) The SERVAUTH resource class is mapped to the required resource type SER. Ensure that the EZA, EZB, and IST resources are defined to the SERVAUTH resource class with a default access of PREVENT. If the product CSSMTP is on the system, no access is given to EZB.CSSMTP of the SERVAUTH resource class. EZB.CSSMTP.sysname.writername.JESnode will be specified and made available to the CSSMTP started task and authenticated users that require access to use CSSMTP for email services. Only authenticated users that require access are permitted access to the second level of the resources in the SERVAUTH resource class. Examples are the network (NETACCESS), port (PORTACCESS), stack (STACKACCESS), and FTP resources in the SERVAUTH resource class. The EZB.STACKACCESS. resource access authorizations restrict access to those started tasks with valid requirements and users with valid FTP access requirements. The EZB.FTP.*.*.ACCESS.HFS) resource access authorizations restrict access to FTP users with specific written documentation showing a valid requirement exists to access OMVS files and Directories. The EZB.INITSTACK.sysname.tcpname resource access authorizations restrict access to TCP/IP stack before policies have been installed to users authorized by the system security plan. The following commands are provided as a sample for implementing resource controls: $KEY(EZB) TYPE(SER) - UID(*) PREVENT CSSMTP. - UID(*) PREVENT CSSMTP.sysname.writername.JESnode UID(authusers) SERVICE(READ) ALLOW FTP.- UID(authusers) SERVICE(READ) ALLOW FTP.sysname.ftpstc.ACCESS.HFS UID(ftpprofile) SERVICE(READ) ALLOW NETACCESS.- UID(authusers) SERVICE(READ) ALLOW PORTACCESS.- UID(authusers) SERVICE(READ) ALLOW STACKACCESS.- UID(authusers) SERVICE(READ) ALLOW STACKACCESS.sysname.TCPIP UID(ftpprofile) SERVICE(READ) ALLOW INITSTACK.- UID(authusers) SERVICE(READ) ALLOW COMPILE 'ACF2.MVA.SER(EZB)' STORE F ACF2,REBUILD(SER)
Rating Info
DISA Cat II. NIST impact 3.
Expert Comment
None
ACF2-CE-000010: IBM z/OS Certificate Name Filtering must be implemented with appropriate authorization and documentation.
If Certificate Name Filtering is in use, collect documentation describing each active filter rule and written approval from the ISSM to use the rule. Issue the following ACF2 commands to list the certificate name filters defined to ACF2: SET CONTROL(GSO) SHOW CERTMAP If no CERTMAP FILTERING TABLES are present, this not a finding. NOTE: Certificate name filters are only valid when their Status is TRUST. Therefore, you may ignore filters with the NOTRUST status. If CERTMAP FILTERING TABLES are present and certificate name filters have a Status of TRUST, certificate name filtering is in use. If Certificate Name Filtering is in use and filtering rules have been documented and approved by the ISSM, this is not a finding. If Certificate Name Filtering is in use and filtering rules have not been documented and approved by the ISSM, this is a finding.
Discussion
To assure accountability and prevent unauthenticated access, organizational users must be identified and authenticated to prevent potential misuse and compromise of the system. Organizational users include organizational employees or individuals the organization deems to have equivalent status of employees (e.g., contractors). Organizational users (and processes acting on behalf of users) must be uniquely identified and authenticated to all accesses, except for the following: 1) Accesses explicitly identified and documented by the organization. Organizations document specific user actions that can be performed on the information system without identification or authentication; and 2) Accesses that occur through authorized use of group authenticators without individual authentication. Organizations may require unique identification of individuals in group accounts (e.g., shared privilege accounts) or for detailed accountability of individual activity.
Fix
Define any Certificate Name Filtering rules when required with documentation and approval by the ISSM.
Rating Info
DISA Cat II. NIST impact 3.
Expert Comment
None
ACF2-SM-000010: IBM z/OS DFSMS resource class(es) must be defined to the GSO CLASMAP record in accordance with security requirements.
From the ISPF Command Shell enter: ACF SET CONTROL(GSO) SHOW CLASMAP If both MGMTCLAS and STORCLAS resource classes are uniquely defined (i.e., not type SAF), this is not a finding.
Discussion
To mitigate the risk of unauthorized access to sensitive information by entities that have been issued certificates by DoD-approved PKIs, all DoD systems (e.g., web servers and web portals) must be properly configured to incorporate access control methods that do not rely solely on the possession of a certificate for access. Successful authentication must not automatically give an entity access to an asset or security boundary. Authorization procedures and controls must be implemented to ensure each authenticated entity also has a validated and current authorization. Authorization is the process of determining whether an entity, once authenticated, is permitted to access a specific asset. Information systems use access control policies and enforcement mechanisms to implement this requirement. The system-wide options control the default settings for determining how the ACP will function when handling requests for access to the operating system environment, ACP, and customer data. The ACP provides the ability to set a number of these fields at the subsystem level. If no setting is found, the system-wide defaults will be used. The improper setting of any one of these fields, individually or in combination with another, can compromise the security of the processing environment. In addition, failure to establish standardized settings for the ACP control options introduces the possibility of exposure during a migration process or contingency plan activation.
Fix
Define the GSO CLASMAP record with the following definitions: MGMTCLAS STORCLAS Ensure both resource classes above are defined uniquely. Example: SHOW SAFDEF SET CONTROL(GSO) INSERT CLASMAP.MGMTCLAS RESOURCE(MGMTCLAS) RSRCTYPE(MGM) ENTITYTLN(8) INSERT CLASMAP.STORCLAS RESOURCE(STORCLAS) RSRCTYPE(STR) ENTITYTLN(8 F ACF2,REFRESH(ALL)
Rating Info
DISA Cat II. NIST impact 3.
Expert Comment
None
ACF2-OS-000140: IBM z/OS NOBUFFS in SMFPRMxx must be properly set (Default is MSG).
Refer to IEASYS00 member in SYS1.PARMLIB Concatenation. Determine proper SMFPRMxx member in SYS1.PARMLIB. If NOBUFFS is set to HALT, this is not a finding. Note: If availability is an overriding concern NOBUFFS can be set to MSG.
Discussion
It is critical that when the operating system is at risk of failing to process audit logs as required, it takes action to mitigate the failure. Audit processing failures include: software/hardware errors; failures in the audit capturing mechanisms; and audit storage capacity being reached or exceeded. Responses to audit failure depend upon the nature of the failure mode. When availability is an overriding concern, other approved actions in response to an audit failure are as follows: 1) If the failure was caused by the lack of audit record storage capacity, the operating system must continue generating audit records if possible (automatically restarting the audit service if necessary), overwriting the oldest audit records in a first-in-first-out manner. 2) If audit records are sent to a centralized collection server and communication with this server is lost or the server fails, the operating system must queue audit records locally until communication is restored or until the audit records are retrieved manually. Upon restoration of the connection to the centralized collection server, action should be taken to synchronize the local audit data with the collection server.
Fix
Configure NOBUFFS to HALT unless availability is an overriding concern then NOBUFFS can be set to MSG.
Rating Info
DISA Cat II. NIST impact 3.
Expert Comment
None
ACF2-ES-000780: ACF2 LOGONIDs must be defined with the required fields completed.
From an ACF Command Screen enter: SET LID LIST * If the below listed fields are complete for all logonids, this is not a finding. NAME User's name UID-String All fields defined in the ACFFDR @UID macro NOTE: A completed NAME field that can either be traced back to a current DD Form 2875 or a Vendor Requirement (example: A Started Task). NOTE: A user may be required to have more than one logonid but users must not share userids.
Discussion
To assure accountability and prevent unauthenticated access, organizational users must be identified and authenticated to prevent potential misuse and compromise of the system. Organizational users include organizational employees or individuals the organization deems to have equivalent status of employees (e.g., contractors). Organizational users (and processes acting on behalf of users) must be uniquely identified and authenticated to all accesses, except for the following: 1) Accesses explicitly identified and documented by the organization. Organizations document specific user actions that can be performed on the information system without identification or authentication; and 2) Accesses that occur through authorized use of group authenticators without individual authentication. Organizations may require unique identification of individuals in group accounts (e.g., shared privilege accounts) or for detailed accountability of individual activity.
Fix
Define every user to ACF2 with a unique userid. (ACF2 calls this a logonid.) To ACF2, a user is an individual, a started task, or a batch job. Every user will be fully identified within ACF2. Complete the following fields for every logonid: NAME - User's name UID-String - All fields defined in the ACFFDR @UID macro All fields that comprise the standard UID string will be filled out for each user as a logonid is added. Example: SET LID INSERT logonid UID(uid string) NAME(user name)
Rating Info
DISA Cat II. NIST impact 3.
Expert Comment
None
ACF2-ES-000670: IBM z/OS Started Tasks must be properly identified and defined to ACF2.
Refer to the site security plan, the system administrator, and system libraries to determine list of stated tasks available on the system. From the ACF command screen enter: SET LID SET VERBOSE LIST IF(STC) If all logonids identified as started tasks have the STC attribute specified, this is not a finding.
Discussion
Started procedures have system generated job statements that do not contain the user, group, or password statements. To enable the started procedure to access the same protected resources that users and groups access, started procedures must have an associated USERID. If a USERID is not associated with the started procedure, the started procedure will not have access to the resources. To ensure accountability and prevent unauthenticated access, organizational users must be identified and authenticated to prevent potential misuse and compromise of the system.
Fix
All started tasks will be assigned an individual logonid. The logonid for a Started Task Control (STC) will be granted the minimum privileges necessary for the STC to function. In addition to the default LID field settings, all STC logonids will have the following field setting: STC Example: SET LID INSERT logonid STC
Rating Info
DISA Cat II. NIST impact 3.
Expert Comment
None
ACF2-FT-000040: IBM z/OS FTP.DATA configuration statements must have a proper BANNER statement with the Standard Mandatory DoD Notice and Consent Banner.
Refer to the FTP.DATA file specified on the SYSFTPD DD statement in the FTP started task JCL. The SYSFTPD DD statement is optional. The search order for FTP.DATA is: /etc/ftp.data SYSFTPD DD statement jobname.FTP.DATA SYS1.TCPPARMS(FTPDATA) tcpip.FTP.DATA Examine the BANNER statement. If the BANNER statement in the FTP Data configuration file specifies an HFS file or data set that contains a logon banner as specified below this is not a finding. The below banner is mandatory and deviations are not permitted except as authorized in writing by the DoD Chief Information Officer. The thrust of this new policy is to make it clear that there is no expectation of privacy when using DoD information systems and all use of DoD information systems is subject to searching, auditing, inspecting, seizing, and monitoring, even if some personal use of a system is permitted: STANDARD MANDATORY DOD NOTICE AND CONSENT BANNER You are accessing a U.S. Government (USG) Information System (IS) that is provided for USG-authorized use only. By using this IS (which includes any device attached to this IS), you consent to the following conditions: -The USG routinely intercepts and monitors communications on this IS for purposes including, but not limited to, penetration testing, COMSEC monitoring, network operations and defense, personnel misconduct (PM), law enforcement (LE), and counterintelligence (CI) investigations. -At any time, the USG may inspect and seize data stored on this IS. -Communications using, or data stored on, this IS are not private, are subject to routine monitoring, interception, and search, and may be disclosed or used for any USG authorized purpose. -This IS includes security measures (e.g., authentication and access controls) to protect USG interests--not for your personal benefit or privacy. -Notwithstanding the above, using this IS does not constitute consent to PM, LE or CI investigative searching or monitoring of the content of privileged communications, or work product, related to personal representation or services by attorneys, psychotherapists, or clergy, and their assistants. Such communications and work product are private and confidential. See User Agreement for details.
Discussion
Display of a standardized and approved use notification before granting access to the operating system ensures privacy and security notification verbiage used is consistent with applicable federal laws, Executive Orders, directives, policies, regulations, standards, and guidance. System use notifications are required only for access via logon interfaces with human users and are not required when such human interfaces do not exist. Satisfies: SRG-OS-000023-GPOS-00006, SRG-OS-000024-GPOS-00007
Fix
Ensure the BANNER statement in the FTP Data configuration file specifies an HFS file or z/OS data set that contains a logon banner. The below banner is mandatory and deviations are not permitted except as authorized in writing by the DoD Chief Information Officer. The thrust of this new policy is to make it clear that there is no expectation of privacy when using DoD information systems and all use of DoD information systems is subject to searching, auditing, inspecting, seizing, and monitoring, even if some personal use of a system is permitted: STANDARD MANDATORY DOD NOTICE AND CONSENT BANNER You are accessing a U.S. Government (USG) Information System (IS) that is provided for USG-authorized use only. By using this IS (which includes any device attached to this IS), you consent to the following conditions: -The USG routinely intercepts and monitors communications on this IS for purposes including, but not limited to, penetration testing, COMSEC monitoring, network operations and defense, personnel misconduct (PM), law enforcement (LE), and counterintelligence (CI) investigations. -At any time, the USG may inspect and seize data stored on this IS. -Communications using, or data stored on, this IS are not private, are subject to routine monitoring, interception, and search, and may be disclosed or used for any USG authorized purpose.
Rating Info
DISA Cat II. NIST impact 3.
Expert Comment
None
ACF2-ES-000210: CA-ACF2 must limit all system PROCLIB data sets to appropriate authorized users.
Refer to the following for the PROCLIB data sets that contain the STCs and TSO logons from the following sources: - MSTJCLxx member used during an IPL. The PROCLIB data sets are obtained from the IEFPDSI and IEFJOBS DD statements. - PROCxx DD statements and JES2 Dynamic PROCLIBs. Where "xx" is the PROCLIB entries for the STC and TSU JOBCLASS configuration definitions. Verify that the accesses to the above PROCLIB data sets are properly restricted. If the following guidance is true, this is not a finding. If the ESM data set access authorizations restrict READ access to all authorized users, this is not a finding. If the ESM data set access authorizations restrict WRITE and/or greater access to systems programming personnel, this is not a finding.
Discussion
To mitigate the risk of unauthorized access to sensitive information by entities that have been issued certificates by DoD-approved PKIs, all DoD systems (e.g., web servers and web portals) must be properly configured to incorporate access control methods that do not rely solely on the possession of a certificate for access. Successful authentication must not automatically give an entity access to an asset or security boundary. Authorization procedures and controls must be implemented to ensure each authenticated entity also has a validated and current authorization. Authorization is the process of determining whether an entity, once authenticated, is permitted to access a specific asset. Information systems use access control policies and enforcement mechanisms to implement this requirement. Access control policies include: identity-based policies, role-based policies, and attribute-based policies. Access enforcement mechanisms include: access control lists, access control matrices, and cryptography. These policies and mechanisms must be employed by the application to control access between users (or processes acting on behalf of users) and objects (e.g., devices, files, records, processes, programs, and domains) in the information system. Satisfies: SRG-OS-000080-GPOS-00048, SRG-OS-000324-GPOS-00125
Fix
Configure ESM data set rules to ensure that all WRITE and/or greater access to all PROCLIBs referenced in the Master JCL and JES2 or JES3 procedure for started tasks (STCs) and TSO logons are restricted to systems programming personnel only. Suggestion on how to update system to be compliant with this vulnerability: NOTE: All examples are only examples and may not reflect your operating environment. Obtain only the PROCLIB data sets that contain STC and TSO procedures. The data sets to be reviewed are obtained using the following steps: - All data sets contained in the MSTJCLxx member in the DD statement concatenation for IEFPDSI and IEFJOBS. - The data set in the PROCxx DD statement concatenation that are within the JES2 procedure or identified in the JES2 dynamic PROCLIB definitions. The specific PROCxx DD statement that is used is obtained from the PROCLIB entry for the JOBCLASSes of STC and TSU. The following is what data sets the process will obtain for analysis: MSTJCL00 //MSTJCL00 JOB MSGLEVEL=(1,1),TIME=1440 //EXEC PGM=IEEMB860,DPRTY=(15,15) //STCINRDR DD SYSOUT=(A,INTRDR) //TSOINRDR DD SYSOUT=(A,INTRDR) //IEFPDSI DD DSN=SYS3.PROCLIB,DISP=SHR <<=== //DD DSN=SYS2.PROCLIB,DISP=SHR <<=== //DD DSN=SYS1.PROCLIB,DISP=SHR <<=== //SYSUADS DD DSN=SYS1.UADS,DISP=SHR //SYSLBC DD DSN=SYS1.BRODCAST,DISP=SHR JES2 //JES2 PROC //IEFPROC EXEC PGM=HASJES20,PARM=NOREQ, //DPRTY=(15,15),TIME=1440,PERFORM=9 //ALTPARM DD DISP=SHR, //DSN=SYS1.PARMLIB(JES2BKUP) //HASPPARM DD DISP=SHR, //DSN=SYS1.PARMLIB(JES2PARM) //PROC00 DD DSN=SYS3.PROCLIB,DISP=SHR <<=== //DD DSN=SYS2.PROCLIB,DISP=SHR <<=== //DD DSN=SYS1.PROCLIB,DISP=SHR <<=== //PROC01 DD DSN=SYS4.USERPROC,DISP=SHR //DD DSN=SYS3.PROCLIB,DISP=SHR //DD DSN=SYS2.PROCLIB,DISP=SHR //DD DSN=SYS1.PROCLIB,DISP=SHR //IEFRDER DD SYSOUT=* //HASPLIST DD DDNAME=IEFRDER JES2 initialization parameter JOBCLASS PROCLIB entries JOBCLASS(*) ACCT=NO, /* ACCT # NOT REQUIRED (DEF.)*/ ... PROCLIB=01, /* DEFAULT TO //PROC01 DD (DEF.)*/ ... JOBCLASS(STC) AUTH=ALL, /* ALLOW ALL COMMANDS (DEF.)*/ ... PROCLIB=00, /* USE //PROC00 DD (DEF.)*/ ... JOBCLASS(TSU) AUTH=ALL, /* ALLOW ALL COMMANDS (DEF.)*/ ... PROCLIB=00, /* USE //PROC00 DD (DEF.)*/ ... PROCLIB data set that will be used in the access authorization process: SYS3.PROCLIB SYS2.PROCLIB SYS1.PROCLIB The following PROCLIB data set will NOT be used or evaluated: SYS4.USERPROC Recommendation for sites: The following are recommendations for the sites to ensure only PROCLIB data sets that contain the STC and TSO procedures are protected. - Remove all application PROCLIB data sets from MSTJCLxx and JES2 procedures. The customer will have all JCL changed to use the JCLLIB JCL statement to refer to the application PROCLIB data sets. Example: //USERPROC JCLLIB ORDER=(SYS4.USERPROC) - Remove all access to the application PROCLIB data sets and only authorize system programming personnel WRITE and/or greater access to these data sets. - Document the application PROCLIB data set access for the customers that require WRITE and/or greater access. Use this documentation as justification for the inappropriate access created by the scripts. - Change MSTJCLxx and JES2 procedure to identify STC and TSO PROCLIB data sets separate from application PROCLIB data sets. The following is a list of actions that can be performed to accomplish this recommendation: a. Ensure that MSTJCLxx contains only PROCLIB data sets that contain STC and TSO procedures. b. If an application PROCLIB data set is required for JES2, ensure that the JES2 procedure specifies more than one PROCxx DD statement concatenation or identified in the JES2 dynamic PROCLIB definitions. Identify one PROCxx DD statement data set concatenation that contains the STC and TSO PROCLIB data sets. Identify one or more additional PROCxx DD statements that can contain any other PROCLIB data sets. The concatenation of the additional PROCxx DD statements can contain the same data sets that are identified in the PROCxx DD statement for STC and TSO. The following is an example of the JES2 procedure: //JES2 PROC //IEFPROC EXEC PGM=HASJES20,PARM=NOREQ, //DPRTY=(15,15),TIME=1440,PERFORM=9 //ALTPARM DD DISP=SHR, //DSN=SYS1.PARMLIB(JES2BKUP) //HASPPARM DD DISP=SHR, //DSN=SYS1.PARMLIB(JES2PARM) //PROC00 DD DSN=SYS3.PROCLIB,DISP=SHR //DD DSN=SYS2.PROCLIB,DISP=SHR //DD DSN=SYS1.PROCLIB,DISP=SHR //PROC01 DD DSN=SYS4.USERPROC,DISP=SHR //DD DSN=SYS3.PROCLIB,DISP=SHR //DD DSN=SYS2.PROCLIB,DISP=SHR //DD DSN=SYS1.PROCLIB,DISP=SHR //IEFRDER DD SYSOUT=* //HASPLIST DD DDNAME=IEFRDER c. Ensure that the JES2 configuration file is changed to specify that the PROCLIB entry for the STC and TSU JOBCLASSes point to the proper PROCxx entry within the JES2 procedure or JES2 dynamic PROCLIB definitions that contain the STC and/or TSO procedures. All other JOBCLASSes can specify a PROCLIB entry that uses the same PROCxx or any other PROCxx DD statement identified in the JES2 procedure or identified in the JES2 dynamic PROCLIB definitions. The following is an example of the JES2 initialization parameters: JOBCLASS(*) ACCT=NO, /* ACCT # NOT REQUIRED (DEF.)*/ ... PROCLIB=01, /* DEFAULT TO //PROC01 DD (DEF.)*/ ... JOBCLASS(STC) AUTH=ALL, /* ALLOW ALL COMMANDS (DEF.)*/ ... PROCLIB=00, /* USE //PROC00 DD (DEF.)*/ ... JOBCLASS(TSU) AUTH=ALL, /* ALLOW ALL COMMANDS (DEF.)*/ ... PROCLIB=00, /* USE //PROC00 DD (DEF.)*/ ... d. Ensure that only system programming personnel are authorized WRITE and/or greater access to PROCLIB data sets that contain STC and TSO procedures.
Rating Info
DISA Cat I. NIST impact 4.
Expert Comment
None
ACF2-ES-000130: CA-ACF2 must limit access to SYS(x).TRACE to system programmers only.
Execute a data set list of access for SYS(x).TRACE files. If the ESM data set rule for SYS1.TRACE restricts access to systems programming personnel and started tasks that perform GTF processing, this is not a finding. If the ESM data set rule for SYS1.TRACE restricts access to others as documented and approved by ISSM, this is not a finding.
Discussion
To mitigate the risk of unauthorized access to sensitive information by entities that have been issued certificates by DoD-approved PKIs, all DoD systems (e.g., web servers and web portals) must be properly configured to incorporate access control methods that do not rely solely on the possession of a certificate for access. Successful authentication must not automatically give an entity access to an asset or security boundary. Authorization procedures and controls must be implemented to ensure each authenticated entity also has a validated and current authorization. Authorization is the process of determining whether an entity, once authenticated, is permitted to access a specific asset. Information systems use access control policies and enforcement mechanisms to implement this requirement. Satisfies: SRG-OS-000080-GPOS-00048, SRG-OS-000324-GPOS-00125
Fix
Configure the ESM access to SYS1.TRACE to be limited to system programmers or started tasks that perform GTF processing. Other user access can be granted as documented and approved by the ISSM.
Rating Info
DISA Cat II. NIST impact 3.
Expert Comment
None
ACF2-OS-002350: IBM z/OS must employ a session manager that conceal, via the session lock, information previously visible on the display with a publicly viewable image.
Ask the system administrator for the configuration parameters for the session manager in use. If there is no session manager in use, this is a finding. If the session manager is not configured to conceal, via the session lock, information previously visible on the display with a publicly viewable image, this is a finding.
Discussion
A session lock is a temporary action taken when a user stops work and moves away from the immediate physical vicinity of the information system but does not log out because of the temporary nature of the absence. The session lock is implemented at the point where session activity can be determined. The operating system session lock event must include an obfuscation of the display screen so as to prevent other users from reading what was previously displayed. Publicly viewable images can include static or dynamic images, for example, patterns used with screen savers, photographic images, solid colors, a clock, a battery life indicator, or a blank screen, with the additional caveat that none of the images convey sensitive information.
Fix
Configure the session manager to conceal, via the session lock, information previously visible on the display with a publicly viewable image.
Rating Info
DISA Cat II. NIST impact 3.
Expert Comment
None
ACF2-ES-000050: The number of ACF2 users granted the special privilege ALLCMDS must be justified.
From the ISPF Command Shell enter: ACF SET LID SET VERBOSE LIST IF(ALLCMDS) If the number of users granted the special privilege ALLCMDS is strictly controlled and access is granted on an as needed basis, this is not a finding. If the number of users granted the special privilege ALLCMDS is not strictly controlled and access is granted on an as needed basis, this is a finding.
Discussion
To mitigate the risk of unauthorized access to sensitive information by entities that have been issued certificates by DoD-approved PKIs, all DoD systems (e.g., web servers and web portals) must be properly configured to incorporate access control methods that do not rely solely on the possession of a certificate for access. Successful authentication must not automatically give an entity access to an asset or security boundary. Authorization procedures and controls must be implemented to ensure each authenticated entity also has a validated and current authorization. Authorization is the process of determining whether an entity, once authenticated, is permitted to access a specific asset. Information systems use access control policies and enforcement mechanisms to implement this requirement. Access control policies include: identity-based policies, role-based policies, and attribute-based policies. Access enforcement mechanisms include: access control lists, access control matrices, and cryptography. These policies and mechanisms must be employed by the application to control access between users (or processes acting on behalf of users) and objects (e.g., devices, files, records, processes, programs, and domains) in the information system.
Fix
Ensure that access to the special privilege ALLCMDS is kept to a minimum and is controlled and documented. Documentation providing justification for access is maintained and filed with the ISSO. Remove any unjustified access.
Rating Info
DISA Cat II. NIST impact 3.
Expert Comment
None
ACF2-ES-000680: ACF2 emergency LOGONIDS with the REFRESH attribute must have the SUSPEND attribute specified.
From the ACF Command screen enter: SET LID LIST IF(REFRESH) If the logonid is an emergency logonid and the REFRESH attribute is not in SUSPEND status, this is a finding.
Discussion
Activity under unusual conditions can indicate hostile activity. For example, what is normal activity during business hours can indicate hostile activity if it occurs during off hours. Depending on mission needs and conditions, account usage restrictions based on conditions and circumstances may be critical to limit access to resources and data to comply with operational or mission access control requirements. Thus, the operating system must be configured to enforce the specific conditions or circumstances under which organization-defined accounts can be used (e.g., by restricting usage to certain days of the week, time of day, or specific durations of time).
Fix
The emergency logonids with the REFRESH attribute must be in SUSPEND status unless actually in use. Example: SET LID CHANGE logonid SUSPEND
Rating Info
DISA Cat II. NIST impact 3.
Expert Comment
None
ACF2-OS-000200: IBM z/OS PASSWORD data set and OS passwords must not be used.
Ask the system administrator to determine if the system PASSWORD data set and OS passwords are being used. If, based on the information provided, it can be determined that the system PASSWORD data set and OS passwords are not used, this is not a finding. If it is evident that OS passwords are utilized, this is a finding.
Discussion
Configuring the operating system to implement organization-wide security implementation guides and security checklists ensures compliance with federal standards and establishes a common security baseline across DoD that reflects the most restrictive security posture consistent with operational requirements. Configuration settings are the set of parameters that can be changed in hardware, software, or firmware components of the system that affect the security posture and/or functionality of the system. Security-related parameters are those parameters impacting the security state of the system, including the parameters required to satisfy other security control requirements. Security-related parameters include, for example: registry settings; account, file, directory permission settings; and settings for functions, ports, protocols, services, and remote connections.
Fix
System programmers will ensure that the old OS Password Protection is not used and any data protected by the old OS Password technology is removed and protection is replaced by the ACP. Review the contents of the PASSWORD data set. Ensure that any protections it provides are provided by the ACP and delete the PASSWORD data set. Access to data sets on z/OS systems can be protected using the OS password capability of MVS. This capability has been available in MVS for many years, and its use is commonly found in data centers. Since the advent of ACPs, the use of OS passwords for file protection has diminished, and is commonly considered archaic and of little use. The use of z/OS passwords is not supported by all the ACPs.
Rating Info
DISA Cat II. NIST impact 3.
Expert Comment
None
ACF2-TN-000010: IBM z/OS PROFILE.TCPIP configuration INACTIVITY statement must be configured to 900 seconds.
Refer to the Profile configuration file specified on the PROFILE DD statement in the TCPIP started task JCL. NOTE: If the INCLUDE statement is coded in the TCP/IP Profile configuration file, the data set specified on this statement must be checked for the following items as well. TELNETPARMS Block (one defined for each port the server is listening to, typically ports 23 and 992) If the TELNETPARMS INACTIVE statement is coded within each TELNETPARMS statement block and specifies a value between 1 and 900, this is not a finding. NOTE: Effective in z/OS release 1.2, the INACTIVE statement can appear in both TELNETGLOBAL and TELNETPARM statement blocks.
Discussion
Automatic session termination addresses the termination of user-initiated logical sessions in contrast to the termination of network connections that are associated with communications sessions (i.e., network disconnect). A logical session (for local, network, and remote access) is initiated whenever a user (or process acting on behalf of a user) accesses an organizational information system. Such user sessions can be terminated (and thus terminate user access) without terminating network sessions. Session termination terminates all processes associated with a user's logical session except those processes that are specifically created by the user (i.e., session owner) to continue after the session is terminated. Conditions or trigger events requiring automatic session termination can include, for example, organization-defined periods of user inactivity, targeted responses to certain types of incidents, and time-of-day restrictions on information system use. This capability is typically reserved for specific operating system functionality where the system owner, data owner, or organization requires additional assurance.
Fix
Configure the PROFILE.TCPIP file as specified below: NOTE: If the INCLUDE statement is coded in the TCP/IP Profile configuration file, the data set specified on this statement must be checked for the following items as well. TELNETPARMS Block (one defined for each port the server is listening to, typically ports 23 and 992) The TELNETPARMS INACTIVE statement is coded within each TELNETPARMS statement block and specifies a value between 1 and 900. INACTIVE statements should not be coded with a value greater than 900 or 0. 0 disables the inactivity timer check. NOTE: Effective in z/OS release 1.2, the INACTIVE statement can appear in both TELNETGLOBAL and TELNETPARM statement blocks.
Rating Info
DISA Cat II. NIST impact 3.
Expert Comment
None
ACF2-ES-000120: CA-ACF2 must limit access to SYSTEM DUMP data sets to appropriate authorized users.
Ask the system administrator and/or DASD administrator to determine the System Dump data sets. Refer to data sets SYS1.DUMPxx. Dump data sets can be identified by reviewing the logical parmlib concatenation data sets for the current COMMNDxx member. Find the COM= that specifies the DUMPDS NAME (DD NAME=name-pattern) entry. The name-pattern is used to identify additional Dump data sets. If ACF2 data set rules for System Dump data sets do not restrict READ, WRITE, and/or ALLOCATE access to only systems programming personnel, this is a finding. If ACF2 data set rules for all System Dump data sets do not restrict READ access to personnel having justification to review these Dump data sets, this is a finding.
Discussion
Access control policies include: identity-based policies, role-based policies, and attribute-based policies. Access enforcement mechanisms include: access control lists, access control matrices, and cryptography. These policies and mechanisms must be employed by the application to control access between users (or processes acting on behalf of users) and objects (e.g., devices, files, records, processes, programs, and domains) in the information system.
Fix
Configure data set rules for access to SYSTEM DUMP data set(s) to be limited to system programmers only, unless a letter justifying access is filed with the ISSO in the site security plan. Evaluate the impact of correcting the deficiency. Develop a plan of action and implement the changes required to restrict access to these data sets.
Rating Info
DISA Cat II. NIST impact 3.
Expert Comment
None
ACF2-JS-000040: IBM z/OS JES2 system commands must be protected in accordance with security requirements.
NOTE: If CLASMAP defines OPERCMDS as anything other than TYPE(OPR), replace OPR below with the appropriate three letters. From the ACF command screen enter: SET RESOURCE(OPR) LIST LIKE(JES-) If the JES2.- resource is defined to the OPERCMDS class with a default access of PREVENT and all access is logged, this is not a finding. If access to JES2 system commands defined in the table in the IBM JES2 Initialization and Tuning Guide titled "JES2 commands with profile names and minimum required authority" is restricted to the appropriate personnel (e.g., operations staff, systems programming personnel, general users), this is not a finding. If all elevated access to JES2 system commands is logged, this is not a finding.
Discussion
To mitigate the risk of unauthorized access to sensitive information by entities that have been issued certificates by DoD-approved PKIs, all DoD systems (e.g., web servers and web portals) must be properly configured to incorporate access control methods that do not rely solely on the possession of a certificate for access. Successful authentication must not automatically give an entity access to an asset or security boundary. Authorization procedures and controls must be implemented to ensure each authenticated entity also has a validated and current authorization. Authorization is the process of determining whether an entity, once authenticated, is permitted to access a specific asset. Information systems use access control policies and enforcement mechanisms to implement this requirement. Access control policies include: identity-based policies, role-based policies, and attribute-based policies. Access enforcement mechanisms include: access control lists, access control matrices, and cryptography. These policies and mechanisms must be employed by the application to control access between users (or processes acting on behalf of users) and objects (e.g., devices, files, records, processes, programs, and domains) in the information system.
Fix
Review the GSO definitions. If CLASMAP defines OPERCMDS as anything other than TYPE(OPR), replace OPR below with the appropriate three letters. Review resource rules for TYPE(OPR). Define the JES2.- resource is defined to the OPERCMDS class with a default access of PREVENT and all access is logged. Define access to JES2 system commands defined in the JES2 system commands defined in the table in the IBM JES2 Initialization and Tuning Guide entitled 'JES2 commands with profile names and minimum required authority' is restricted to the appropriate personnel (e.g., operations staff, systems programming personnel, general users). Define access to specific JES2 system commands is logged as indicated in the table JES2 system commands defined in the table in the IBM JES2 Initialization and Tuning Guide titled "JES2 commands with profile names and minimum required authority". Assure that elevated access is logged. Some ACF2 Examples: $KEY(JES2) TYPE(OPR) CANCEL.BAT UID(oper) SERVICE(READ,UPDATE) LOG DISPLAY.JOB UID(*) SERVICE(READ) LOG START.INITIATOR UID(oper) SERVICE(DELETE) LOG START.LINE UID(oper) SERVICE(DELETE) LOG STOP.INITIATOR UID(oper) SERVICE(DELETE) LOG STOP.LINE UID(oper) SERVICE(DELETE) LOG - UID(*) PREVENT
Rating Info
DISA Cat II. NIST impact 3.
Expert Comment
None
ACF2-SH-000040: IBM z/OS SSH daemon must be configured to only use the SSHv2 protocol.
Locate the SSH daemon configuration file, which may be found in /etc/ssh/ directory. Alternately: From UNIX System Services ISPF Shell navigate to ribbon select tools. Select option 1 - Work with Processes. If SSH Daemon is not active, this is not a finding. Examine SSH daemon configuration file. If the variables "Protocol 2,1" or "Protocol 1" are defined on a line without a leading comment, this is a finding.
Discussion
In order to prevent unauthorized connection of devices, unauthorized transfer of information, or unauthorized tunneling (i.e., embedding of data types within data types), organizations must disable or restrict unused or unnecessary physical and logical ports/protocols on information systems. Operating systems are capable of providing a wide variety of functions and services. Some of the functions and services provided by default may not be necessary to support essential organizational operations. Additionally, it is sometimes convenient to provide multiple services from a single component (e.g., VPN and IPS); however, doing so increases risk over limiting the services provided by any one component. To support the requirements and principles of least functionality, the operating system must support the organizational requirements, providing only essential capabilities and limiting the use of ports, protocols, and/or services to only those required, authorized, and approved to conduct official business or to address authorized quality of life issues.
Fix
Edit the sshd_config file and set the "Protocol" setting to "2".
Rating Info
DISA Cat I. NIST impact 4.
Expert Comment
None
ACF2-OS-000120: IBM z/OS system administrators must develop an automated process to collect and retain SMF data.
Ask the system administrator if there is an automated process is in place to collect and retain all SMF data produced on the system. If, based on the information provided, it can be determined that an automated process is in place to collect and retain all SMF data produced on the system, this is not a finding. If it cannot be determined this process exists and is being adhered to, this is a finding.
Discussion
Information stored in one location is vulnerable to accidental or incidental deletion or alteration. Off-loading is a common process in information systems with limited audit storage capacity.
Fix
The ISSO will ensure that an automated process is in place to collect SMF data. Review SMF data collection and retention processes. Verify processes are automatically started to dump SMF collection files immediately upon their becoming full. To ensure that all SMF data is collected in a timely manner, and to reduce the risk of data loss, the site will ensure that automated mechanisms are in place to collect and retain all SMF data produced on the system. Dump the SMF files (MANx) in systems based on the following guidelines: Dump each SMF file as it fills up during the normal course of daily processing. - Dump all remaining SMF data at the end of each processing day, or - Establish a process using Audit logging.
Rating Info
DISA Cat II. NIST impact 3.
Expert Comment
None
ACF2-ES-000250: CA-ACF2 must limit Write or greater access to SYS1.LPALIB to system programmers only.
Execute a data set list of access for SYS1.LPALIB. If any of the following is true, this is a finding. - The ACF2 data set rules for SYS1.LPALIB do not restrict WRITE and/or ALLOCATE access to only z/OS systems programming personnel. - The ACF2 data set rules for SYS1.LPALIB do not specify that all (i.e., failures and successes) WRITE and/or ALLOCATE access will be logged.
Discussion
To mitigate the risk of unauthorized access to sensitive information by entities that have been issued certificates by DoD-approved PKIs, all DoD systems (e.g., web servers and web portals) must be properly configured to incorporate access control methods that do not rely solely on the possession of a certificate for access. Successful authentication must not automatically give an entity access to an asset or security boundary. Authorization procedures and controls must be implemented to ensure each authenticated entity also has a validated and current authorization. Authorization is the process of determining whether an entity, once authenticated, is permitted to access a specific asset. Information systems use access control policies and enforcement mechanisms to implement this requirement. Access control policies include: identity-based policies, role-based policies, and attribute-based policies. Access enforcement mechanisms include: access control lists, access control matrices, and cryptography. These policies and mechanisms must be employed by the application to control access between users (or processes acting on behalf of users) and objects (e.g., devices, files, records, processes, programs, and domains) in the information system. Satisfies: SRG-OS-000080-GPOS-00048, SRG-OS-000259-GPOS-00100, SRG-OS-000324-GPOS-00125
Fix
Review access authorization to critical system files. Evaluate the impact of correcting the deficiency. Develop a plan of action and implement the changes required to protect SYS1.LPALIB. Configure update and allocate access to SYS1.LPALIB to be limited to system programmers only and all update and allocate access is logged.
Rating Info
DISA Cat I. NIST impact 4.
Expert Comment
None
ACF2-US-000080: IBM z/OS UNIX MVS data sets with z/OS UNIX components must be properly protected.
If the ESM data set rules for each of the data sets listed in the table below restrict UPDATE and ALLOCATE access to systems programming personnel, this is not a finding. MVS DATA SETS WITH z/OS UNIX COMPONENTS DATA SET NAME/MASK MAINTENANCE TYPE FUNCTION SYS1.ABPX* Distribution IBM z/OS UNIX ISPF panels, messages, tables, clists SYS1.AFOM* Distribution IBM z/OS UNIX Application Services SYS1.BPA.ABPA* Distribution IBM z/OS UNIX Connection Scaling Process Mgr. SYS1.CMX.ACMX* Distribution IBM z/OS UNIX Connection Scaling Connection Mgr. SYS1.SBPX* Target IBM z/OS UNIX ISPF panels, messages, tables, clists SYS1.SFOM* Target IBM z/OS UNIX Application Services SYS1.CMX.SCMX* Target IBM z/OS UNIX Connection Scaling Connection Mgr.
Discussion
Access control policies include: identity-based policies, role-based policies, and attribute-based policies. Access enforcement mechanisms include: access control lists, access control matrices, and cryptography. These policies and mechanisms must be employed by the application to control access between users (or processes acting on behalf of users) and objects (e.g., devices, files, records, processes, programs, and domains) in the information system. Satisfies: SRG-OS-000080-GPOS-00048, SRG-OS-000259-GPOS-00100
Fix
Define ESM data set rules for each of the data sets listed in the table below restrict UPDATE and ALLOCATE access to systems programming personnel. The data sets designated as distribution data sets should have all access restricted to systems programming personnel. TSO/E users who also use z/OS UNIX should have read access to the SYS1.SBPX* data sets. Read access for all users to the remaining target data sets is at the site's discretion. All other access must be restricted to systems programming personnel. MVS DATA SETS WITH z/OS UNIX COMPONENTS DATA SET NAME/MASK MAINTENANCE TYPE FUNCTION SYS1.ABPX* Distribution IBM z/OS UNIX ISPF panels, messages, tables, clists SYS1.AFOM* Distribution IBM z/OS UNIX Application Services SYS1.BPA.ABPA* Distribution IBM z/OS UNIX Connection Scaling Process Mgr. SYS1.CMX.ACMX* Distribution IBM z/OS UNIX Connection Scaling Connection Mgr. SYS1.SBPX* Target IBM z/OS UNIX ISPF panels, messages, tables, clists SYS1.SFOM* Target IBM z/OS UNIX Application Services SYS1.CMX.SCMX* Target IBM z/OS UNIX Connection Scaling Connection Mgr.
Rating Info
DISA Cat II. NIST impact 3.
Expert Comment
None
ACF2-TC-000090: IBM z/OS TCPIP.DATA configuration statement must contain the DOMAINORIGIN or DOMAIN specified for each TCP/IP defined.
Refer to the Data configuration file specified on the SYSTCPD DD statement in the TCPIP started task JCL. Note: If GLOBALTCPIPDATA is specified, any TCPIP.DATA statements contained in the specified file or data set take precedence over any TCPIP.DATA statements found using the appropriate environment's (native MVS or z/OS UNIX) search order. If GLOBALTCPIPDATA is not specified, the appropriate environment's (Native MVS or z/OS UNIX) search order is used to locate TCPIP.DATA. If the configuration statements specified in the TCP/IP Data configuration file guidance are true, this is not a finding. DOMAINORIGIN/DOMAIN (The DOMAIN statement is functionally equivalent to the DOMAINORIGIN Statement)
Discussion
If data origin authentication and data integrity verification are not performed, the resultant response could be forged, it may have come from a poisoned cache, the packets could have been intercepted without the resolver's knowledge, or resource records could have been removed which would result in query failure or denial of service. Data origin authentication verification must be performed to thwart these types of attacks. Each client of name resolution services either performs this validation on its own or has authenticated channels to trusted validation providers. Information systems that provide name and address resolution services for local clients include, for example, recursive resolving or caching Domain Name System (DNS) servers. DNS client resolvers either perform validation of DNSSEC signatures, or clients use authenticated channels to recursive resolvers that perform such validations. This is not applicable if DNSSEC is not implemented on the local network.
Fix
Configure the TCPIP.DATA file to include the following: DOMAINORIGIN/DOMAIN - Specifies the default domain name used for DNS searches. Note: If GLOBALTCPIPDATA is specified, any TCPIP.DATA statements contained in the specified file or data set take precedence over any TCPIP.DATA statements found using the appropriate environment's (native MVS or z/OS UNIX) search order. If GLOBALTCPIPDATA is not specified, the appropriate environment's (Native MVS or z/OS UNIX) search order is used to locate TCPIP.DATA.
Rating Info
DISA Cat II. NIST impact 3.
Expert Comment
None
ACF2-OS-000180: IBM z/OS SMF collection files (i.e., SYS1.MANx) access must be limited to appropriate users and/or batch jobs that perform SMF dump processing.
Refer to the SMFPRMxx member in SYS1.PARMLIB. Determine the SMF and/or Logstream data set name. If the following statements are true, this is not a finding. - The ACF2 data set rules for the SMF data collection files (e.g., SYS1.MAN* or IFASMF.SYS1.*) restrict ALLOCATE access to only z/OS systems programming personnel. - The ACF2 data set rules for the SMF data collection files (e.g., SYS1.MAN* or IFASMF.SYS1.*) restrict WRITE access to z/OS systems programming personnel and/or batch jobs that perform SMF dump processing and others as approved by the ISSM. - The ACF2 data set rules for the SMF data collection files (e.g., SYS1.MAN* or IFASMF.SYS1.*) restrict READ access to auditors and others approved by the ISSM. - The ACF2 data set rules for SMF data collection files (e.g., SYS1.MAN* or IFASMF.SYS1.*) specify that all (i.e., failures and successes) WRITE and/or ALLOCATE access is logged.
Discussion
SMF data collection is the system activity journaling facility of the z/OS system. Unauthorized access could result in the compromise of logging and recording of the operating system environment, ACF2, and customer data. Unauthorized disclosure of audit records can reveal system and configuration data to attackers, thus compromising its confidentiality. Audit information includes all information (e.g., audit records, audit settings, audit reports) needed to successfully audit operating system activity. Satisfies: SRG-OS-000057-GPOS-00027, SRG-OS-000058-GPOS-00028, SRG-OS-000059-GPOS-00029, SRG-OS-000256-GPOS-00097, CCI-001494, SRG-OS-000257-GPOS-00098, SRG-OS-000258-GPOS-00099, SRG-OS-000080-GPOS-00048, SRG-OS-000206-GPOS-00084, SRG-OS-000324-GPOS-00125
Fix
Ensure that WRITE or greater authority to SMF collection files is limited to only systems programming staff and and/or batch jobs that perform SMF dump processing, access can be granted to others as determined by ISSM. Ensure that read access is limited to auditors. READ access may be granted to others as determined by the ISSM. Ensure the accesses are being logged. Ensure that all (i.e., failures and successes) WRITE and/or ALLOCATE access are logged. Ensure read access failures are logged.
Rating Info
DISA Cat II. NIST impact 3.
Expert Comment
None
ACF2-ES-000650: ACF2 LOGONIDs with the ACCOUNT, LEADER, or SECURITY attribute must be properly scoped.
From the ACF command screen enter: SET LID LIST IF(ACCOUNT) LIST IF(LEADER) LIST IF(SECURITY) Review all logonids for specific groups with the attributes ACCOUNT, LEADER, or SECURITY. If each has the SCPLIST attribute specified properly according to job function and areas of responsibility, this is not a finding. NOTE: SCPLST attributes are not required for Domain Level Security Admin Logonids and BATCH Logonids that administer and modify the entire ACF2 environment to include GSO records, data set and resource rules, etc. or run audit reports.
Discussion
Activity under unusual conditions can indicate hostile activity. For example, what is normal activity during business hours can indicate hostile activity if it occurs during off hours. Depending on mission needs and conditions, account usage restrictions based on conditions and circumstances may be critical to limit access to resources and data to comply with operational or mission access control requirements. Thus, the operating system must be configured to enforce the specific conditions or circumstances under which organization-defined accounts can be used (e.g., by restricting usage to certain days of the week, time of day, or specific durations of time).
Fix
The following user attributes allow update of the ACF2 databases for administering users, data set access rules, and Infostorage records. When granted to a logonid, restrict the scope of the following attributes using an associated SCPLIST (scope list) record: ACCOUNT LEADER SECURITY NOTE: SCPLST attributes are not required for Domain Level Security Admin Logonids and BATCH Logonids that administer and modify the entire ACF2 environment to include GSO records, data set and resource rules, etc. or run audit reports.
Rating Info
DISA Cat II. NIST impact 3.
Expert Comment
None
ACF2-ES-000970: ACF2 security data sets and/or databases must be properly protected.
Determine all associated ACF2 security data sets and/or databases. If the ACF2 data set rules for ACF2 security data sets and/or databases restrict READ access to auditors and DASD batch, this is not a finding. If the ACF2 data set rules for ACF2 security data sets and/or databases restrict READ and/or greater access to z/OS systems programming personnel, security personnel, and/or batch jobs that perform ACP maintenance, this is not a finding. If all (i.e., failures and successes) data set access authorities (i.e., READ, WRITE, ALLOCATE, and CONTROL) for ACP security data sets and/or databases are logged, this is not a finding.
Discussion
An isolation boundary provides access control and protects the integrity of the hardware, software, and firmware that perform security functions. Security functions are the hardware, software, and/or firmware of the information system responsible for enforcing the system security policy and supporting the isolation of code and data on which the protection is based. Operating systems implement code separation (i.e., separation of security functions from nonsecurity functions) in a number of ways, including through the provision of security kernels via processor rings or processor modes. For non-kernel code, security function isolation is often achieved through file system protections that serve to protect the code on disk and address space protections that protect executing code. Developers and implementers can increase the assurance in security functions by employing well-defined security policy models; structured, disciplined, and rigorous hardware and software development techniques; and sound system/security engineering principles. Implementation may include isolation of memory space and libraries. Operating systems restrict access to security functions through the use of access control mechanisms and by implementing least privilege capabilities. Preventing non-privileged users from executing privileged functions mitigates the risk that unauthorized individuals or processes may gain unnecessary access to information or privileges. Privileged functions include, for example, establishing accounts, performing system integrity checks, or administering cryptographic key management activities. Non-privileged users are individuals that do not possess appropriate authorizations. Circumventing intrusion detection and prevention mechanisms or malicious code protection mechanisms are examples of privileged functions that require protection from non-privileged users. Satisfies: SRG-OS-000134-GPOS-00068, SRG-OS-000080-GPOS-00048, SRG-OS-000259-GPOS-00100, SRG-OS-000324-GPOS-00125
Fix
Configure ACF2 READ and/or greater access rules for ACF2 files and/or databases as limited to system programmers and/or security personnel, and/or batch jobs that perform ACP maintenance. READ access can be given to auditors and DASD batch. All accesses to ACP files and/or databases are logged.
Rating Info
DISA Cat I. NIST impact 4.
Expert Comment
None
ACF2-IC-000010: IBM Integrated Crypto Service Facility (ICSF) Configuration parameters must be correctly specified.
Refer to the CSFPRMxx member in the logical PARMLIB concatenation. If the configuration parameters are specified as follows, this is not a finding. REASONCODES(ICSF) COMPAT(NO) SSM(NO) SSM can be dynamically set by defining the CSF.SSM.ENABLE SAF profile within the XFACILIT resource Class. If this profile is not limited to authorized personnel this is a finding. CHECKAUTH(YES) FIPSMODE(YES,FAIL(YES)) AUDITKEYLIFECKDS (TOKEN(YES),LABEL(YES)). AUDITKEYLIFEPKDS (TOKEN(YES),LABEL(YES)). AUDITKEYLIFETKDS (TOKENOBJ(YES),SESSIONOBJ(YES)). AUDITKEYUSGCKDS (TOKEN(YES),LABEL(YES),INTERVAL(n)). AUDITKEYUSGPKDS (TOKEN(YES),LABEL(YES),INTERVAL(n)). AUDITPKCS11USG (TOKENOBJ(YES),SESSIONOBJ(YES),NOKEY(YES),INTERVAL(n)). DEFAULTWRAP - This parameter can be determined by the site. ENHANCED wrapping specifies the new X9.24 compliant CBC wrapping is used. If DEFAULTWRAP is not specified, the default wrapping method will be ORIGINAL for both internal and external tokens. Starting with ICSF FMID HCR77C0, the value for this option can be updated without restarting ICSF by using either the SETICSF command or the ICSF Multi-Purpose service. If this access is not restricted to appropriate personnel, this is a finding. Note: Other options may be site-defined.
Discussion
IBM Integrated Crypto Service Facility (ICSF) product has the ability to use privileged functions and/or have access to sensitive data. Failure to properly configure parameter values could potentially the integrity of the base product which could result in compromising the operating system or sensitive data.
Fix
Evaluate the impact associated with implementation of the control options. Develop a plan of action to implement the control options for CSFPRMxx as specified below: REASONCODES(ICSF) COMPAT(NO) SSM(NO) SSM can be dynamically set by defining the CSF.SSM.ENABLE SAF profile within the XFACILIT resource class. This profile must limited to authorized personnel. CHECKAUTH(YES) FIPSMODE(YES,FAIL(YES)) AUDITKEYLIFECKDS (TOKEN(YES),LABEL(YES)). AUDITKEYLIFEPKDS (TOKEN(YES),LABEL(YES)). AUDITKEYLIFETKDS (TOKENOBJ(YES),SESSIONOBJ(YES)). AUDITKEYUSGCKDS (TOKEN(YES),LABEL(YES),INTERVAL(n)). AUDITKEYUSGPKDS (TOKEN(YES),LABEL(YES),INTERVAL(n)). AUDITPKCS11USG (TOKENOBJ(YES),SESSIONOBJ(YES),NOKEY(YES),INTERVAL(n)). DEFAULTWRAP - This parameter can be determined by the site. ENHANCED wrapping specifies the new X9.24 compliant CBC wrapping is used. If DEFAULTWRAP is not specified, the default wrapping method will be ORIGINAL for both internal and external tokens. Starting with ICSF FMID HCR77C0, the value for this option can be updated without restarting ICSF by using either the SETICSF command or the ICSF Multi-Purpose service. This access must be restricted to appropriate personnel. Note: Other options may be site-defined.
Rating Info
DISA Cat II. NIST impact 3.
Expert Comment
None
ACF2-ES-000740: ACF2 BLPPGM GSO record must not be defined.
From the ISPF Command Shell enter: ACF SET CONTROL(GSO) LIST BLPPGM If the BLPPGM record is defined, this is a finding.
Discussion
In order to prevent unauthorized connection of devices, unauthorized transfer of information, or unauthorized tunneling (i.e., embedding of data types within data types), organizations must disable or restrict unused or unnecessary physical and logical ports/protocols on information systems. Operating systems are capable of providing a wide variety of functions and services. Some of the functions and services provided by default may not be necessary to support essential organizational operations. Additionally, it is sometimes convenient to provide multiple services from a single component (e.g., VPN and IPS); however, doing so increases risk over limiting the services provided by any one component. To support the requirements and principles of least functionality, the operating system must support the organizational requirements, providing only essential capabilities and limiting the use of ports, protocols, and/or services to only those required, authorized, and approved to conduct official business or to address authorized quality of life issues.
Fix
The BLPPGM GSO value indicates that ACF2 does not control the programs authorized to use tape bypass label processing (BLP). Delete the BLPPGM from GSO options.
Rating Info
DISA Cat II. NIST impact 3.
Expert Comment
None
ACF2-OS-000360: IBM z/OS Policy agent must contain a policy that protects against or limits the effects of Denial of Service (DoS) attacks by ensuring the operating system is implementing rate-limiting measures on impacted network interfaces.
Examine the Policy Agent policy statements. If it can be determined that policy that protects against or limits the effects of denial-of-service (DoS) attacks by ensuring the operating system is implementing rate-limiting measures on impacted network interfaces, this is not a finding.
Discussion
DoS is a condition when a resource is not available for legitimate users. When this occurs, the organization either cannot accomplish its mission or must operate at degraded capacity. This requirement addresses the configuration of the operating system to mitigate the impact of DoS attacks that have occurred or are ongoing on system availability. For each system, known and potential DoS attacks must be identified and solutions for each type implemented. A variety of technologies exist to limit or, in some cases, eliminate the effects of DoS attacks (e.g., limiting processes or establishing memory partitions). Employing increased capacity and bandwidth, combined with service redundancy, may reduce the susceptibility to some DoS attacks.
Fix
Develop Policy application and policy agent to protect against or limit the effects of denial-of-service (DoS) attacks by ensuring the operating system is implementing rate-limiting measures on impacted network interfaces.
Rating Info
DISA Cat II. NIST impact 3.
Expert Comment
None
ACF2-ES-000220: CA-ACF2 access to the System Master Catalog must be properly protected.
Refer to SYSCATxx member of SYS1.NUCLEUS. Multiple SYSCATxx members may be defined if so refer to Master Catalog message for IPL. If the member is not found, refer to the appropriate LOADxx member of SYS1.PARMLIB. If data set rules for the Master Catalog do not restrict greater than "READ" access to only z/OS systems programming personnel, this is a finding. If Products or procedures requiring system programmer access for system level maintenance meet the following specific case: - The batch job or procedure must be documented in the SITE Security Plan. - Reside in a data set that is restricted to systems programmers' access only. If the above is true, this is not a finding. If data set rules for the Master Catalog do not specify that all (i.e., failures and successes) greater than "READ" access will be logged, this is a finding.
Discussion
To mitigate the risk of unauthorized access to sensitive information by entities that have been issued certificates by DoD-approved PKIs, all DoD systems (e.g., web servers and web portals) must be properly configured to incorporate access control methods that do not rely solely on the possession of a certificate for access. Successful authentication must not automatically give an entity access to an asset or security boundary. Authorization procedures and controls must be implemented to ensure each authenticated entity also has a validated and current authorization. Authorization is the process of determining whether an entity, once authenticated, is permitted to access a specific asset. Information systems use access control policies and enforcement mechanisms to implement this requirement. Access control policies include: identity-based policies, role-based policies, and attribute-based policies. Access enforcement mechanisms include: access control lists, access control matrices, and cryptography. These policies and mechanisms must be employed by the application to control access between users (or processes acting on behalf of users) and objects (e.g., devices, files, records, processes, programs, and domains) in the information system. Satisfies: SRG-OS-000080-GPOS-00048, SRG-OS-000324-GPOS-00125
Fix
Review access authorization to critical system files. Evaluate the impact of correcting the deficiency. Develop a plan of action and implement the changes as required to protect the MASTER CATALOG. Configure the ESM rules for system master catalog to only allow access above "READ" to systems programmers and those authorized by the Site Security Plan. Configure ESM rules for the system master catalog to allow access above "READ" to systems programmers ONLY. Configure ESM rules for the system master catalog to allow any Products or procedures system programmer access for system level maintenance that meet the following specific case: - The batch job or procedure must be documented in the SITE Security Plan. - Reside in a data set that is restricted to systems programmers' access only. All greater than read access must be logged.
Rating Info
DISA Cat I. NIST impact 4.
Expert Comment
None
ACF2-OS-000090: IBM z/OS special privileges must be assigned on an as-needed basis to LOGONIDs associated with STCs and LOGONIDs that need to execute TSO in batch.
From the ISPF Command Shell enter: ACF SET LID SET VERBOSE LIST IF(ACCTPRIV OR CONSOLE OR OPERATOR OR MOUNT) If the ACCTPRIV privilege is restricted to security personnel, this is not a finding. If the CONSOLE and OPERATOR privileges are restricted to authorized systems personnel (e.g., systems programming personnel, operations staff, etc), this is not a finding. If the MOUNT privilege is restricted to DASD batch users only, this is not a finding.
Discussion
To mitigate the risk of unauthorized access to sensitive information by entities that have been issued certificates by DoD-approved PKIs, all DoD systems (e.g., web servers and web portals) must be properly configured to incorporate access control methods that do not rely solely on the possession of a certificate for access. Successful authentication must not automatically give an entity access to an asset or security boundary. Authorization procedures and controls must be implemented to ensure each authenticated entity also has a validated and current authorization. Authorization is the process of determining whether an entity, once authenticated, is permitted to access a specific asset. Information systems use access control policies and enforcement mechanisms to implement this requirement. Access control policies include: identity-based policies, role-based policies, and attribute-based policies. Access enforcement mechanisms include: access control lists, access control matrices, and cryptography. These policies and mechanisms must be employed by the application to control access between users (or processes acting on behalf of users) and objects (e.g., devices, files, records, processes, programs, and domains) in the information system.
Fix
Review all Logonids for the following and ensure that only authorized users with justification are given access to the privileges. The ACCTPRIV privilege is restricted for used to the domain level security personnel (ISSO/ISSM). The CONSOLE and OPERATOR privileges are restricted to authorized systems personnel (e.g., systems programming personnel, operations staff, etc). The MOUNT privilege is restricted to DASD batch users only on an as-needed basis to execute TSO in batch. Ensure that all privileges are kept to a minimum and are controlled and documented.
Rating Info
DISA Cat II. NIST impact 3.
Expert Comment
None
ACF2-US-000170: IBM z/OS User exits for the FTP Server must not be used without proper approval and documentation.
Refer to the Data configuration file specified on the SYSFTPD DD statement in the FTP started task JCL. Refer to the file(s) allocated by the STEPLIB DD statement in the FTP started task JCL. Refer to the libraries specified in the system Linklist and LPA. If any FTP Server exits are in use, identify them and validate that they were reviewed for integrity and approved by the site AO. If the following items are in effect for FTP Server user exits, this is not a finding: The FTCHKCMD, FTCHKIP, FTCHKJES, FTCHKPWD, FTPSMFEX and FTPOSTPR modules are not located in the FTP daemon's STEPLIB, Linklist, or LPA. NOTE: The ISPF ISRFIND utility can be used to search the system Linklist and LPA for specific modules.
Discussion
In order to prevent unauthorized connection of devices, unauthorized transfer of information, or unauthorized tunneling (i.e., embedding of data types within data types), organizations must disable or restrict unused or unnecessary physical and logical ports/protocols on information systems. Operating systems are capable of providing a wide variety of functions and services. Some of the functions and services provided by default may not be necessary to support essential organizational operations. Additionally, it is sometimes convenient to provide multiple services from a single component (e.g., VPN and IPS); however, doing so increases risk over limiting the services provided by any one component. To support the requirements and principles of least functionality, the operating system must support the organizational requirements, providing only essential capabilities and limiting the use of ports, protocols, and/or services to only those required, authorized, and approved to conduct official business or to address authorized quality of life issues. Several user exit points in the FTP Server component are available to permit customization of its operating behavior. These exits can be used to modify functions such as FTP command usage, client connection controls, post processing tasks, and SMF record modifications. Without proper review and adequate documentation of these exit programs, undesirable operations and degraded security may result. This exposure could lead to unauthorized access impacting data integrity or the availability of some system services, or contribute to the loss of accountability and hamper security audit activities.
Fix
Review the configuration statements in the FTP.DATA file. Review the FTP daemon STEPLIB, system Linklist, and Link Pack Area libraries. If FTP Server exits are enabled or present, and have not been approved by the site ISSM and not securely written and implemented by the site systems programmer, they should not be installed. Verify that none of the following exits are installed unless they have met the requirements listed above: FTCHKCMD FTCHKIP FTCHKJES FTCHKPWD FTPOSTPR FTPSMFEX
Rating Info
DISA Cat II. NIST impact 3.
Expert Comment
None
ACF2-OS-003430: IBM z/OS system administrator must develop a procedure to offload SMF files to a different system or media than the system being audited.
Ask the system administrator for the procedure to offload SMF files to a different system or media than the system being audited. If the procedure does not exist, this is a finding.
Discussion
Information stored in one location is vulnerable to accidental or incidental deletion or alteration. Off-loading is a common process in information systems with limited audit storage capacity.
Fix
Develop a procedure to offload SMF files to a different system or media than the system being audited.
Rating Info
DISA Cat II. NIST impact 3.
Expert Comment
None
ACF2-ES-000760: IBM z/OS user account for the UNIX kernel (OMVS) must be properly defined to the security database.
From the ISPF Command Shell enter: ACF SET LID SET VERBOSE LIST OMVS SECTION(ALL) PROFILE(OMVS) If OMVS is defined as follows, this is not a finding. No access to interactive on-line facilities (e.g., TSO, CICS, etc). Default group specified as OMVSGRP or STCOMVS UID(0) HOME directory specified as "/" Shell program specified as "/bin/sh" If OMVS is not defined as specified in above, this is a finding.
Discussion
To assure accountability and prevent unauthenticated access, organizational users must be identified and authenticated to prevent potential misuse and compromise of the system. Organizational users include organizational employees or individuals the organization deems to have equivalent status of employees (e.g., contractors). Organizational users (and processes acting on behalf of users) must be uniquely identified and authenticated to all accesses, except for the following: 1) Accesses explicitly identified and documented by the organization. Organizations document specific user actions that can be performed on the information system without identification or authentication; and 2) Accesses that occur through authorized use of group authenticators without individual authentication. Organizations may require unique identification of individuals in group accounts (e.g., shared privilege accounts) or for detailed accountability of individual activity.
Fix
Define the OMVS (IBM default name for USS Kernel), as specified below: No access to interactive on-line facilities (e.g., TSO, CICS, etc.) Default group specified as OMVSGRP or STCOMVS UID(0) HOME directory specified as "/" Shell program specified as "/bin/sh"
Rating Info
DISA Cat II. NIST impact 3.
Expert Comment
None
ACF2-ES-000290: CA-ACF2 must limit Write or greater access to all LPA libraries to system programmers only.
From any ISPF input line, enter TSO ISRDDN LPA. If all of the following are untrue, this is not a finding. If any of the following is true, this is a finding. The ACP data set rules for LPA libraries do not restrict WRITE and/or ALLOCATE access to only z/OS systems programming personnel. The ACP data set rules for LPA libraries do not specify that all (i.e., failures and successes) WRITE and/or ALLOCATE access will be logged.
Discussion
To mitigate the risk of unauthorized access to sensitive information by entities that have been issued certificates by DoD-approved PKIs, all DoD systems (e.g., web servers and web portals) must be properly configured to incorporate access control methods that do not rely solely on the possession of a certificate for access. Successful authentication must not automatically give an entity access to an asset or security boundary. Authorization procedures and controls must be implemented to ensure each authenticated entity also has a validated and current authorization. Authorization is the process of determining whether an entity, once authenticated, is permitted to access a specific asset. Information systems use access control policies and enforcement mechanisms to implement this requirement. Access control policies include: identity-based policies, role-based policies, and attribute-based policies. Access enforcement mechanisms include: access control lists, access control matrices, and cryptography. These policies and mechanisms must be employed by the application to control access between users (or processes acting on behalf of users) and objects (e.g., devices, files, records, processes, programs, and domains) in the information system. Satisfies: SRG-OS-000080-GPOS-00048, SRG-OS-000259-GPOS-00100, SRG-OS-000324-GPOS-00125
Fix
Review access authorization to critical system files. Evaluate the impact of correcting the deficiency. Develop a plan of action and implement the changes required to protect LPA Libraries. Configure the update and allocate access to all LPA libraries to be limited to system programmers only and all update and allocate access is logged.
Rating Info
DISA Cat I. NIST impact 4.
Expert Comment
None
ACF2-US-000040: IBM z/OS UNIX resources must be protected in accordance with security requirements.
From the ISPF Command Shell enter: ACF SET RESOURCE(SUR) SET VERBOSE LIST LIKE(BPX-) If the ACF2 rules for all BPX.SRV.user TYPE(SUR) resources specify a default access of NONE, this is not a finding. If the ACF2 rules for all BPX.SRV.user TYPE(SUR) resources restrict access to system software processes (e.g., web servers) that act as servers under z/OS UNIX, this is not a finding. If the ACF2 rules for all BPX.SRV.user SURROGAT resources restrict access to authorized users identified in the Site Security Plan, this is not a finding.
Discussion
To mitigate the risk of unauthorized access to sensitive information by entities that have been issued certificates by DoD-approved PKIs, all DoD systems (e.g., web servers and web portals) must be properly configured to incorporate access control methods that do not rely solely on the possession of a certificate for access. Successful authentication must not automatically give an entity access to an asset or security boundary. Authorization procedures and controls must be implemented to ensure each authenticated entity also has a validated and current authorization. Authorization is the process of determining whether an entity, once authenticated, is permitted to access a specific asset. Information systems use access control policies and enforcement mechanisms to implement this requirement.
Fix
Configure BPX. SRV.userid resources to be properly protected and access restricted to appropriate system tasks or systems programming personnel. SURROGAT class BPX resources are used in conjunction with server applications that are performing tasks on behalf of client users that may not supply an authenticator to the server. This can be the case when clients are otherwise validated or when the requested service is performed from userids representing groups. The default access for each BPX.SRV.userid resource must be no access. Access can be permitted only to system software processes that act as servers under OS/390 UNIX (e.g., web servers) and users whose access an approval are identified in the Site Security Plan. Example: SET R(SUR) $KEY(BPX) TYPE(SUR) SRV.INTERNAL UID(FJB****STC******IMWEBSRV) SERVICE(READ) LOG SRV.PRIVATE UID(FJB****STC******IMWEBSRV) SERVICE(READ) LOG SRV.PUBLIC UID(FJB****STC******IMWEBSRV) SERVICE(READ) LOG SRV.WEBADM UID(FJB****STC******IMWEBSRV) SERVICE(READ) LOG - UID(*) PREVENT
Rating Info
DISA Cat II. NIST impact 3.
Expert Comment
None
ACF2-SH-000010: IBM z/OS SMF recording options for the SSH daemon must be configured to write SMF records for all eligible events.
Locate the SSH daemon configuration file which may be found in "/etc/ssh/" directory. Alternately: From UNIX System Services ISPF Shell, navigate to ribbon select tools. Select option 1 - Work with Processes. If SSH Daemon is not active, this is not a finding. Examine SSH daemon configuration file. If ServerSMF is not coded with ServerSMF TYPE119_U83 or is commented out, this is a finding.
Discussion
Remote access services, such as those providing remote access to network devices and information systems, which lack automated monitoring capabilities, increase risk and make remote user access management difficult at best. Remote access is access to DoD nonpublic information systems by an authorized user (or an information system) communicating through an external, non-organization-controlled network. Remote access methods include, for example, dial-up, broadband, and wireless. Automated monitoring of remote access sessions allows organizations to detect cyber attacks and also ensure ongoing compliance with remote access policies by auditing connection activities of remote access capabilities, such as Remote Desktop Protocol (RDP), on a variety of information system components (e.g., servers, workstations, notebook computers, smartphones, and tablets). Satisfies: SRG-OS-000032-GPOS-00013, SRG-OS-000392-GPOS-00172
Fix
Configure the SERVERSMF statement in the SSH Daemon configuration file to TYPE119_U83.
Rating Info
DISA Cat II. NIST impact 3.
Expert Comment
None
ACF2-SM-000050: IBM z/OS DFSMS resources must be protected in accordance with the proper security requirements.
From the ISPF Command Shell enter: ACF SET RESOURCE(FAC) SET VERBOSE LIST LIKE(STG-) If all the following guidance is true, this is not a finding. The resource rule for FACILITY (FAC) $KEY(STGADMIN) has a default access of PREVENT. STGADMIN.DPDSRN.olddsname is restricted to System Programmers and all access is logged. The STGADMIN.IGD.ACTIVATE.CONFIGURATION is restricted to System Programmers and all access is logged. The STGADMIN.IGG.DEFDEL.UALIAS is restricted to Centralized and Decentralized Security personnel and System Programmers and all access is logged. The resource STGADMIN.IGG.CATALOG.SECURITY.CHANGE is defined with access of PREVENT. Note: the resource STGADMIN.IGG.CATALOG.SECURITY.CHANGE can be defined with read access for migration purposes. If it is a detailed migration plan must be documented and filed by the ISSM that determines a definite migration period. All access must be logged. At the completion of migration this resource must be configured with access = PREVENT. The following resources and prefixes may be available to the end-user. STGADMIN.ADR.COPY.CNCURRNT STGADMIN.ADR.COPY.FLASHCPY STGADMIN.ADR.COPY.TOLERATE.ENQF STGADMIN.ADR.DUMP.CNCURRNT STGADMIN.ADR.DUMP.TOLERATE.ENQF STGADMIN.ADR.RESTORE.TOLERATE.ENQF STGADMIN.ARC.ENDUSER. STGADMIN.IGG.ALTER.SMS The following resource is restricted to Application Production Support Team members, Automated Operations, DASD managers, and System programmers. STGADMIN.IDC.DCOLLECT The following resources are restricted to Application Production Support Team members, DASD managers, and System programmers. STGADMIN.ARC.CANCEL STGADMIN.ARC.LIST STGADMIN.ARC.QUERY STGADMIN.ARC.REPORT STGADMIN.DMO.CONFIG STGADMIN.IFG.READVTOC STGADMIN.IGG.DELGDG.FORCE The following resource prefixes, at a minimum, are restricted to DASD managers and System programmers. STGADMIN.ADR STGADMIN.ANT STGADMIN.ARC STGADMIN.DMO STGADMIN.ICK STGADMIN.IDC STGADMIN.IFG STGADMIN.IGG STGADMIN.IGWSHCDS The following Storage Administrator functions prefix is restricted to DASD managers and System programmers and all access is logged. STGADMIN.ADR.STGADMIN.
Discussion
To mitigate the risk of unauthorized access to sensitive information by entities that have been issued certificates by DoD-approved PKIs, all DoD systems (e.g., web servers and web portals) must be properly configured to incorporate access control methods that do not rely solely on the possession of a certificate for access. Successful authentication must not automatically give an entity access to an asset or security boundary. Authorization procedures and controls must be implemented to ensure each authenticated entity also has a validated and current authorization. Authorization is the process of determining whether an entity, once authenticated, is permitted to access a specific asset. Information systems use access control policies and enforcement mechanisms to implement this requirement. Access control policies include: identity-based policies, role-based policies, and attribute-based policies. Access enforcement mechanisms include: access control lists, access control matrices, and cryptography. These policies and mechanisms must be employed by the application to control access between users (or processes acting on behalf of users) and objects (e.g., devices, files, records, processes, programs, and domains) in the information system. Satisfies: SRG-OS-000080-GPOS-00048, SRG-OS-000324-GPOS-00125
Fix
Configure access requirements for SMS Resources as follows. Define the guidelines to ensure the resource type, resources, and/or generic equivalent are followed. (Note: The resource type, resources, and/or resource prefixes identified below are examples of a possible installation. The actual resource type, resources, and/or resource prefixes are determined when the product is actually installed on a system through the product's installation guide and can be site specific.) The ACF2 resources are defined with a default access of PREVENT. Ensure that the following items are in effect: Ensure that no access is given to the high-level STGADMIN resource. Example: $KEY(STGADMIN) TYPE(FAC) - UID(*) PREVENT Ensure no access is given to resource STGADMIN.IGG.CATALOG.SECURITY.CHANGE. Example: $KEY(STGADMIN) TYPE(FAC) IGG.STGADMIN.IGG.CATALOG.SECURITY.CHANGE-UID(*) PREVENT Note: the resource STGADMIN.IGG.CATALOG.SECURITY.CHANGE can be defined with read access for migration purposes. If it is a detailed migration plan must be documented and filed with the ISSM that determines a definite migration period. All access must be logged. At the completion of migration this resource must be configured with access = PREVENT The STGADMIN.DPDSRN.olddsname is restricted to System Programmers and all access is logged. Example: $KEY(STGADMIN) TYPE(FAC) DPDSRN.- UID(sysprgmr) SERVICE(READ) LOG DPDSRN.- UID(*) PREVENT The STGADMIN.IGD.ACTIVATE.CONFIGURATION is restricted to System Programmers and all access is logged. Example: $KEY(STGADMIN) TYPE(FAC) IGD.ACTIVATE.CONFIGURATION UID(sysprgmr) SERVICE(READ) LOG IGD.ACTIVATE.CONFIGURATION UID(*) PREVENT The STGADMIN.IGG.DEFDEL.UALIAS is restricted to System Programmers and Security personnel and all access is logged. Example: $KEY(STGADMIN) TYPE(FAC) IGG.DEFDEL.UALIAS UID(seca) SERVICE(READ) LOG IGG.DEFDEL.UALIAS UID(secd) SERVICE(READ) LOG IGG.DEFDEL.UALIAS UID(sysprgmr) SERVICE(READ) LOG IGG.DEFDEL.UALIAS UID(*) PREVENT The following resources and prefixes may be available to the end-user. STGADMIN.ADR.COPY.CNCURRNT STGADMIN.ADR.COPY.FLASHCPY STGADMIN.ADR.COPY.TOLERATE.ENQF STGADMIN.ADR.DUMP.CNCURRNT STGADMIN.ADR.DUMP.TOLERATE.ENQF STGADMIN.ADR.RESTORE.TOLERATE.ENQF STGADMIN.ARC.ENDUSER. STGADMIN.IGG.ALTER.SMS Example: $KEY(STGADMIN) TYPE(FAC) ADR.COPY.CNCURRNT.- UID(endusers) SERVICE(READ) The following resource is restricted to Application Production Support Team members, Automated Operations, DASD managers, and System programmers. STGADMIN.IDC.DCOLLECT Example: $KEY(STGADMIN) TYPE(FAC) IDC.DCOLLECT.- UID(apps) SERVICE(READ) IDC.DCOLLECT.- UID(auto) SERVICE(READ) IDC.DCOLLECT.- UID(dasb) SERVICE(READ) IDC.DCOLLECT.- UID(dasd) SERVICE(READ) IDC.DCOLLECT.- UID(sysprgmr) SERVICE(READ) IDC.DCOLLECT.- UID(*) PREVENT The following resources are restricted to Application Production Support Team members, DASD managers, and System programmers. STGADMIN.ARC.CANCEL STGADMIN.ARC.LIST STGADMIN.ARC.QUERY STGADMIN.ARC.REPORT STGADMIN.DMO.CONFIG STGADMIN.IFG.READVTOC STGADMIN.IGG.DELGDG.FORCE Example: $KEY(STGADMIN) TYPE(FAC) ARC.CANCEL.- UID(apps) SERVICE(READ) ARC.CANCEL.- UID(dasb) SERVICE(READ) ARC.CANCEL.- UID(dasd) SERVICE(READ) ARC.CANCEL.- UID(sysprgmr) SERVICE(READ) ARC.CANCEL.- UID(*) PREVENT The following resource prefixes, at a minimum, are restricted to DASD managers and System programmers. STGADMIN.ADR STGADMIN.ANT STGADMIN.ARC STGADMIN.DMO STGADMIN.ICK STGADMIN.IDC STGADMIN.IFG STGADMIN.IGG STGADMIN.IGWSHCDS Example: $KEY(STGADMIN) TYPE(FAC) ADR. - UID(dasb) SERVICE(READ) ADR.- UID(dasd) SERVICE(READ) ADR.- UID(sysprgmr) SERVICE(READ) ADR.- UID(*) PREVENT The following Storage Administrator functions prefix is restricted to DASD managers and System programmers and all access is logged. STGADMIN.ADR.STGADMIN. Example: $KEY(STGADMIN) TYPE(FAC) ADR.STGADMIN.- UID(dasb) SERVICE(READ) LOG ADR.STGADMIN.- UID(dasd) SERVICE(READ) LOG ADR.STGADMIN.- UID(sysprgmr) SERVICE(READ) LOG ADR.STGADMIN.- UID(*) PREVENT
Rating Info
DISA Cat II. NIST impact 3.
Expert Comment
None
ACF2-SL-000020: IBM z/OS Syslog daemon must be started at z/OS initialization.
SYSLOGD may be started from the shell, a cataloged procedure (STC), or the BPXBATCH program. Additionally, other mechanisms (e.g., a job scheduler) may be used to automatically start the Syslog daemon. To thoroughly analyze this requirement you may need to view the OS SYSLOG using SDSF, find the last IPL, and look for the initialization of SYSLOGD. If the Syslog daemon SYSLOGD is started automatically during the initialization of the z/S/ system, this is not a finding.
Discussion
To assure accountability and prevent unauthenticated access, organizational users must be identified and authenticated to prevent potential misuse and compromise of the system. Organizational users include organizational employees or individuals the organization deems to have equivalent status of employees (e.g., contractors). Organizational users (and processes acting on behalf of users) must be uniquely identified and authenticated to all accesses, except for the following: 1) Accesses explicitly identified and documented by the organization. Organizations document specific user actions that can be performed on the information system without identification or authentication; and 2) Accesses that occur through authorized use of group authenticators without individual authentication. Organizations may require unique identification of individuals in group accounts (e.g., shared privilege accounts) or for detailed accountability of individual activity.
Fix
Review the files used to initialize tasks during system IPL (e.g., /etc/rc, SYS1.PARMLIB, any Job scheduler definitions) to ensure the Syslog daemon is automatically started during z/OS system initialization. It is important that syslogd be started during the initialization phase of the z/OS system to ensure that significant messages are not lost. As with other z/OS UNIX daemons, there is more than one way to start SYSLOGD. It can be started as a process in the /etc/rc file or as a z/OS started task.
Rating Info
DISA Cat II. NIST impact 3.
Expert Comment
None
ACF2-ES-000660: ACF2 LOGONIDs associated with started tasks that have the MUSASS attribute and the requirement to submit jobs on behalf of its users must have the JOBFROM attribute as required.
From the ACF command screen enter: SET LID SET VERBOSE LIst IF(MUSASS & STC) If any started task logonid that has the MUSASS attribute and the requirement to submit jobs on behalf of its users does not have the JOBFROM attribute, this is a finding.
Discussion
Activity under unusual conditions can indicate hostile activity. For example, what is normal activity during business hours can indicate hostile activity if it occurs during off hours. Depending on mission needs and conditions, account usage restrictions based on conditions and circumstances may be critical to limit access to resources and data to comply with operational or mission access control requirements. Thus, the operating system must be configured to enforce the specific conditions or circumstances under which organization-defined accounts can be used (e.g., by restricting usage to certain days of the week, time of day, or specific durations of time).
Fix
Ensure that if MUSASS has the requirement to submit jobs on behalf of its users, the STC logonid has the JOBFROM attribute specified. If the MUSASS has the requirement to submit jobs on behalf of its users, the STC logonid will also have the following attribute: JOBFROM Example: SET LID CHANGE logonid STC JOBFROM
Rating Info
DISA Cat II. NIST impact 3.
Expert Comment
None
ACF2-US-000130: IBM z/OS UNIX HFS permission bits and audit bits for each directory must be properly protected or specified.
From the ISPF Command Shell enter: omvs cd / ls -alW If the HFS permission bits and user audit bits for each directory and file match or are more restrictive than the specified settings listed in the table below, this is not a finding. SYSTEM DIRECTORY SECURITY SETTINGS DIRECTORY PERMISSION BITS USER AUDIT BITS FUNCTION / [root] 755 faf Root level of all file systems. Holds critical mount points. /bin 1755 fff Shell scripts and executables for basic functions /dev 1755 fff Character-special files used when logging into the OMVS shell and during C language program compilation. Files are created during system IPL and on a per-demand basis. /etc 1755 faf Configuration programs and files (usually with locally customized data) used by z/OS UNIX and other product initialization processes /lib 1755 fff System libraries including dynamic link libraries and files for static linking /samples 1755 fff Sample configuration and other files /tmp 1777 fff Temporary data used by daemons, servers, and users. Note: /tmp must have the sticky bit on to restrict file renames and deletions. /u 1755 fff Mount point for user home directories and optionally for third-party software and other local site files /usr 1755 fff Shell scripts, executables, help (man) files and other data. Contains sub-directories (e.g., lpp) and mount points used by program products that may be in separate file systems. /var 1775 fff Dynamic data used internally by products and by elements and features of z/OS UNIX. The following represents a hierarchy for permission bits from least restrictive to most restrictive: 7 rwx (least restrictive) 6 rw- 3 -wx 2 -w- 5 r-x 4 r-- 1 --x 0 --- (most restrictive) The possible audit bits settings are as follows: f log for failed access attempts a log for failed and successful access - no auditing
Discussion
If the operating system were to allow any user to make changes to software libraries, then those changes might be implemented without undergoing the appropriate testing and approvals that are part of a robust change management process. This requirement applies to operating systems with software libraries that are accessible and configurable, as in the case of interpreted languages. Software libraries also include privileged programs which execute with escalated privileges. Only qualified and authorized individuals must be allowed to obtain access to information system components for purposes of initiating changes, including upgrades and modifications.
Fix
Define the UNIX permission bits and user audit bits on each of the HFS directory in the table below to be equal or more restrictive. SYSTEM DIRECTORY SECURITY SETTINGS DIRECTORY PERMISSION BITS USER AUDIT BITS FUNCTION / [root] 755 faf Root level of all file systems. Holds critical mount points. /bin 1755 fff Shell scripts and executables for basic functions /dev 1755 fff Character-special files used when logging into the OMVS shell and during C language program compilation. Files are created during system IPL and on a per-demand basis. /etc 1755 faf Configuration programs and files (usually with locally customized data) used by z/OS UNIX and other product initialization processes /lib 1755 fff System libraries including dynamic link libraries and files for static linking /samples 1755 fff Sample configuration and other files /tmp 1777 fff Temporary data used by daemons, servers, and users. Note: /tmp must have the sticky bit on to restrict file renames and deletions. /u 1755 fff Mount point for user home directories and optionally for third-party software and other local site files /usr 1755 fff Shell scripts, executables, help (man) files and other data. Contains sub-directories (e.g., lpp) and mount points used by program products that may be in separate file systems. /var 1775 fff Dynamic data used internally by products and by elements and features of z/OS UNIX. The following represents a hierarchy for permission bits from least restrictive to most restrictive: 7 rwx (least restrictive) 6 rw- 3 -wx 2 -w- 5 r-x 4 r-- 1 --x 0 --- (most restrictive) The possible audit bits settings are as follows: f log for failed access attempts a log for failed and successful access - no auditing The following commands are a sample of the commands to be used (from a user account with an effective UID(0)) to update the permission bits and audit bits: chmod 0755 / chaudit w=sf,rx+f / chmod 0755 /bin chaudit rwx=f /bin
Rating Info
DISA Cat II. NIST impact 3.
Expert Comment
None
ACF2-TN-000070: IBM z/OS PROFILE.TCPIP configuration for the TN3270 Telnet Server must have INACTIVE statement properly specified.
Refer to the Profile configuration file specified on the PROFILE DD statement in the TCPIP started task JCL. NOTE: If the INCLUDE statement is coded in the TCP/IP Profile configuration file, the data set specified on this statement must be checked for the following items as well. TELNETPARMS Block (one defined for each port the server is listening to, typically ports 23 and 992) If the TELNETPARMS INACTIVE statement is coded within each TELNETPARMS statement block and specifies a value between 1 and 900, this is not a finding. NOTE: Effective in z/OS release 1.2, the INACTIVE statement can appear in both TELNETGLOBAL and TELNETPARM statement blocks.
Discussion
Terminating an idle session within a short time period reduces the window of opportunity for unauthorized personnel to take control of a management session enabled on the console or console port that has been left unattended. In addition, quickly terminating an idle session will also free up resources committed by the managed network element. Terminating network connections associated with communications sessions includes, for example, de-allocating associated TCP/IP address/port pairs at the operating system level, and de-allocating networking assignments at the application level if multiple application sessions are using a single operating system-level network connection. This does not mean that the operating system terminates all sessions or network access; it only ends the inactive session and releases the resources associated with that session.
Fix
Configure the PROFILE.TCPIP file as specified below: NOTE: If the INCLUDE statement is coded in the TCP/IP Profile configuration file, the data set specified on this statement must be checked for the following items as well. "TELNETPARMS Block (one defined for each port the server is listening to, typically ports 23 and 992)" The TELNETPARMS INACTIVE statement is coded within each TELNETPARMS statement block and specifies a value between 1 and 900. INACTIVE statements should not be coded with a value greater than 900 or 0. 0 disables the inactivity timer check. NOTE: Effective in z/OS release 1.2, the INACTIVE statement can appear in both TELNETGLOBAL and TELNETPARM statement blocks.
Rating Info
DISA Cat II. NIST impact 3.
Expert Comment
None
ACF2-ES-000960: ACF2 RESVOLS GSO record value must be set to Volmask(-). Any other setting requires documentation justifying the change.
From an ACF command screen, enter: SET CONTROL(GSO) LIST RESVOLS If the GSO RESVOLS record values conform to the following requirements, this is not a finding. VOLMASK(-) NOTE: Local changes will be documented in writing with supporting documentation. If there is any deviation from the above requirements in the GSO RESVOLS record values, this is a finding.
Discussion
The RESVOLS record defines DASD and mass storage volumes for which CA ACF2 is to provide protection at the data set name level. Information at rest refers to the state of information when it is located on a secondary storage device (e.g., disk drive and tape drive, when used for backups) within an operating system. This requirement addresses protection of user-generated data, as well as operating system-specific configuration data. Organizations may choose to employ different mechanisms to achieve confidentiality and integrity protections, as appropriate, in accordance with the security category and/or classification of the information.
Fix
Define the GSO RESVOLS record values to conform to the following requirements. VOLMASK(-) Example: SET C(GSO) INSERT RESVOLS VOLMASK(-) F ACF2,REFRESH(SECVOLS)
Rating Info
DISA Cat II. NIST impact 3.
Expert Comment
None
ACF2-TN-000040: IBM z/OS TN3270 Telnet Server configuration statement MSG10 text must have the Standard Mandatory DoD Notice and Consent Banner.
Refer to the Profile configuration file specified on the PROFILE DD statement in the TCPIP started task JCL. If all USS tables referenced in BEGINVTAM USSTCP statements include MSG10 text that specifies the Standard logon banner this is not a finding. The below banner is mandatory and deviations are not permitted except as authorized in writing by the DoD Chief Information Officer. The thrust of this new policy is to make it clear that there is no expectation of privacy when using DoD information systems and all use of DoD information systems is subject to searching, auditing, inspecting, seizing, and monitoring, even if some personal use of a system is permitted: STANDARD MANDATORY DOD NOTICE AND CONSENT BANNER You are accessing a U.S. Government (USG) Information System (IS) that is provided for USG-authorized use only. By using this IS (which includes any device attached to this IS), you consent to the following conditions: -The USG routinely intercepts and monitors communications on this IS for purposes including, but not limited to, penetration testing, COMSEC monitoring, network operations and defense, personnel misconduct (PM), law enforcement (LE), and counterintelligence (CI) investigations. -At any time, the USG may inspect and seize data stored on this IS. -Communications using, or data stored on, this IS are not private, are subject to routine monitoring, interception, and search, and may be disclosed or used for any USG authorized purpose. -This IS includes security measures (e.g., authentication and access controls) to protect USG interests--not for your personal benefit or privacy. -Notwithstanding the above, using this IS does not constitute consent to PM, LE or CI investigative searching or monitoring of the content of privileged communications, or work product, related to personal representation or services by attorneys, psychotherapists, or clergy, and their assistants. Such communications and work product are private and confidential. See User Agreement for details. DOD requires that a logon warning banner be displayed. Within the TN3270 Telnet Server, the banner can be implemented through the USS table that is specified on a BEGINVTAM USSTCP statement. The text associated with message ID 10 (i.e., MSG10) in the USS table is sent to clients that are subject to USSTCP processing.
Discussion
A logon banner can be used to inform users about the environment during the initial logon. In the DISA environment, logon banners are used to warn users against unauthorized entry and the possibility of legal action for unauthorized users, and advise all users that system use constitutes consent to monitoring. Failure to display a logon warning banner without this type of information could adversely impact the ability to prosecute unauthorized users and users who abuse the system. Satisfies: SRG-OS-000023-GPOS-00006, SRG-OS-000024-GPOS-00007
Fix
Review all USS tables referenced in BEGINVTAM USSTCP statements in the PROFILE.TCPIP file. Ensure the MSG10 text specifies a logon banner in accordance with DISA requirements. See MGG10 below: STANDARD MANDATORY DOD NOTICE AND CONSENT BANNER You are accessing a U.S. Government (USG) Information System (IS) that is provided for USG-authorized use only. By using this IS (which includes any device attached to this IS), you consent to the following conditions: -The USG routinely intercepts and monitors communications on this IS for purposes including, but not limited to, penetration testing, COMSEC monitoring, network operations and defense, personnel misconduct (PM), law enforcement (LE), and counterintelligence (CI) investigations. -At any time, the USG may inspect and seize data stored on this IS. -Communications using, or data stored on, this IS are not private, are subject to routine monitoring, interception, and search, and may be disclosed or used for any USG authorized purpose. -This IS includes security measures (e.g., authentication and access controls) to protect USG interests--not for your personal benefit or privacy. -Notwithstanding the above, using this IS does not constitute consent to PM, LE or CI investigative searching or monitoring of the content of privileged communications, or work product, related to personal representation or services by attorneys, psychotherapists, or clergy, and their assistants. Such communications and work product are private and confidential. See User Agreement for details. DOD requires that a logon warning banner be displayed. Within the TN3270 Telnet Server, the banner can be implemented through the USS table that is specified on a BEGINVTAM USSTCP statement. The text associated with message ID 10 (i.e., MSG10) in the USS table is sent to clients that are subject to USSTCP processing.
Rating Info
DISA Cat II. NIST impact 3.
Expert Comment
None
ACF2-OS-000050: IBM z/OS system administrator must develop a process notify appropriate personnel when accounts are modified.
Ask the system Administrator for the documented process to notify appropriate personnel when accounts are modified. If there is no documented process, this is a finding.
Discussion
Once an attacker establishes access to a system, the attacker often attempts to create a persistent method of reestablishing access. One way to accomplish this is for the attacker to modify an existing account. Notification of account modification is one method for mitigating this risk. A comprehensive account management process will ensure an audit trail which documents the modification of operating system user accounts and notifies the system administrator and ISSO of changes. Such a process greatly reduces the risk that accounts will be surreptitiously created and provides logging that can be used for forensic purposes. To address access requirements, many operating systems can be integrated with enterprise-level authentication/access/auditing mechanisms that meet or exceed access control policy requirements.
Fix
Develop a documented process to notify appropriate personnel when accounts are modified.
Rating Info
DISA Cat II. NIST impact 3.
Expert Comment
None
ACF2-ES-000720: ACF2 LINKLST GSO record if specified must only contains trusted system data sets.
From the ACF Command screen enter: SET CONTROL(GSO) LIST LINKLST If the GSO LINKLST record values conform to the following requirements, this is not a finding. Specifies one or more partitioned data sets considered part of the system link (SYS1.LINKLIB) during data set access validation. Only trusted system data sets will be listed. Application libraries will never be included. Example: LIBRARY(SYS1.LINKLIB SYS2A.FDR.LOADLIB) If there is any deviation from the above requirements in the GSO LINKLST record values, this is a finding.
Discussion
Control of program execution is a mechanism used to prevent execution of unauthorized programs. Some operating systems may provide a capability that runs counter to the mission or provides users with functionality that exceeds mission requirements. This includes functions and services installed at the operating system level. Some of the programs, installed by default, may be harmful or may not be necessary to support essential organizational operations (e.g., key missions, functions). Removal of executable programs is not always possible; therefore, establishing a method of preventing program execution is critical to maintaining a secure system baseline. Methods for complying with this requirement include restricting execution of programs in certain environments, while preventing execution in other environments; or limiting execution of certain program functionality based on organization-defined criteria (e.g., privileges, subnets, sandboxed environments, or roles).
Fix
Configure the LINKLIST GSO value if specified only contains trusted system data sets. Specifies one or more partitioned data sets considered part of the system link (SYS1.LINKLIB) during data set access validation. Only trusted system data sets will be listed. Application libraries will never be included. Example: SET C(GSO) INSERT LINKLST LIBRARY(SYS1.LINKLIB SYS2A.FDR.LOADLIB) F ACF2,REFRESH(LINKLST)
Rating Info
DISA Cat II. NIST impact 3.
Expert Comment
None
ACF2-ES-000070: IBM z/OS Sensitive Utility Controls must be properly defined and protected.
Refer to the table of Sensitive Utilities resources and/or generic equivalent as detailed in the table. If the ACF2 resources are defined with a default access of PREVENT, this is not a finding. If the ACF2 resource access authorizations restrict access to the appropriate personnel according to the site security plan, this not a finding. If the ACF2 resource logging is correctly specified, this is not a finding. Sensitive Utility Controls Program Product Function AHLGTF z/OS System Activity Tracing HHLGTF IHLGTF ICPIOCP z/OS System Configuration IOPIOCP IXPIOCP IYPIOCP IZPIOCP BLSROPTR z/OS Data Management DEBE OS/DEBE Data Management DITTO OS/DITTO Data Management FDRZAPOP FDR Product Internal Modification GIMSMP SMP/E Change Management Product ICKDSF z/OS DASD Management IDCSC01 z/OS IDCAMS Set Cache Module IEHINITT z/OS Tape Management IFASMFDP z/OS SMF Data Dump Utility IND$FILE z/OS PC to Mainframe File Transfer (Applicable only for classified systems) CSQJU003 IBM WebSphereMQ CSQJU004 CSQUCVX CSQ1LOGP CSQUTIL WHOIS z/OS Share MOD to identify user name from USERID. Restricted to data center personnel only.
Discussion
To mitigate the risk of unauthorized access to sensitive information by entities that have been issued certificates by DoD-approved PKIs, all DoD systems (e.g., web servers and web portals) must be properly configured to incorporate access control methods that do not rely solely on the possession of a certificate for access. Successful authentication must not automatically give an entity access to an asset or security boundary. Authorization procedures and controls must be implemented to ensure each authenticated entity also has a validated and current authorization. Authorization is the process of determining whether an entity, once authenticated, is permitted to access a specific asset. Information systems use access control policies and enforcement mechanisms to implement this requirement. Access control policies include: identity-based policies, role-based policies, and attribute-based policies. Access enforcement mechanisms include: access control lists, access control matrices, and cryptography. These policies and mechanisms must be employed by the application to control access between users (or processes acting on behalf of users) and objects (e.g., devices, files, records, processes, programs, and domains) in the information system.
Fix
Refer to the Site Security plan for Sensitive Programs/Utilities for lists the resources, access requirements, and logging requirements for Sensitive Utilities. Configure ACF2 resources to be defined with a default access of PREVENT. Configure ACF2 resource access authorizations to restrict access to the appropriate personnel. Configure ACF2 resource logging to be correctly specified. The following commands are provided as a sample for implementing resource controls: $KEY(AHLGTF) TYPE(PGM) UID(stcg) LOG UID(*) PREVENT F ACF2,REBUILD(PGM)
Rating Info
DISA Cat II. NIST impact 3.
Expert Comment
None
ACF2-JS-000050: IBM z/OS JES2 spool resources must be controlled in accordance with security requirements.
From there ACF Command screen enter: SET RESOURCE(SPL) LIST LIKE(localnodeid-) If the accesses to the JESSPOOL resources are properly restricted using the following guidance, this is not a finding. NOTE: If CLASMAP defines JESSPOOL as anything other than TYPE(SPL), replace SPL below with the appropriate three letters. Review the JESSPOOL report for resource rules with the following naming convention. These rules may be fully qualified, be specified as generic, or be specified with masking as indicated below: localnodeid.logonid.jobname.jobid.dsnumber.name localnodeid - The name of the node on which the SYSIN or SYSOUT data set currently resides. logonid - The logonid associated with the job. This is the logonid ACF2 uses for validation purposes when the job runs. jobname - The name that appears in the name field of the JOB statement. jobid - The job number JES2 assigned to the job. dsnumber - The unique data set number JES2 assigned to the spool data set. A D is the first character of this qualifier. name -The name of the data set specified in the DSN= parameter of the DD statement. If the JCL did not specify DSN= on the DD statement that creates the spool data set, JES2 uses a question mark (?). All users have access to their own JESSPOOL resources. The localnodeid. resource will be restricted to only system programmers, operators, and automated operations personnel, with access to allow all SERVICEs or any combination of SERVICE(...). All access will be logged. (localnodeid. resource includes all generic and/or masked permissions, example: localnodeid.-.-, localnodeid.-, etc) The JESSPOOL localnodeid.userid.jobname.jobid.dsnumber.name, whether generic and/or masked, can be made available to users, when approved by the ISSO. Access will be identified at the minimum access for the user to accomplish the users function, SERVICE(READ, UPDATE, DELETE, ADD). All access will be logged. An example is team members within a team, providing the capability to view, help, and/or debug other team member jobs/processes. CSSMTP will be restricted to localnodeid.userid.jobname.jobid.dsnumber.name, whether generic and/or masked when approved by the ISSO. All access will be logged. Spooling products users (CA-SPOOL, CA View, etc) will be restricted to localnodeid.userid.jobname.jobid.dsnumber.name, whether generic and/or masked when approved by the ISSO. Logging of access is not required.
Discussion
To mitigate the risk of unauthorized access to sensitive information by entities that have been issued certificates by DoD-approved PKIs, all DoD systems (e.g., web servers and web portals) must be properly configured to incorporate access control methods that do not rely solely on the possession of a certificate for access. Successful authentication must not automatically give an entity access to an asset or security boundary. Authorization procedures and controls must be implemented to ensure each authenticated entity also has a validated and current authorization. Authorization is the process of determining whether an entity, once authenticated, is permitted to access a specific asset. Information systems use access control policies and enforcement mechanisms to implement this requirement. Access control policies include: identity-based policies, role-based policies, and attribute-based policies. Access enforcement mechanisms include: access control lists, access control matrices, and cryptography. These policies and mechanisms must be employed by the application to control access between users (or processes acting on behalf of users) and objects (e.g., devices, files, records, processes, programs, and domains) in the information system.
Fix
Configure JESSPOOL resources as defined below. The JESSPOOL resources may be fully qualified, be specified as generic, or be specified with masking as indicated below: localnodeid.userid.jobname.jobid.dsnumber.name localnodeid - The name of the node on which the SYSIN or SYSOUT data set currently resides. userid - The userid associated with the job. This is the userid used for validation purposes when the job runs. jobname - The name that appears in the name field of the JOB statement. jobid - The job number JES2 assigned to the job. dsnumber - The unique data set number JES2 assigned to the spool data set. A D is the first character of this qualifier. name - The name of the data set specified in the DSN= parameter of the DD statement. If the JCL did not specify DSN= on the DD statement that creates the spool data set, JES2 uses a question mark (?). The CLASMAP defines JESSPOOL as TYPE(SPL). Example: SHOW CLASMAP By default a user has access only to that user's own JESSPOOL resources. However, situations exist where a user legitimately requires access to jobs that run under another user's userid. In particular, if a user routes SYSOUT to an external writer, the external writer should have access to that user's SYSOUT. The localnodeid. resource will be restricted to only system programmers, operators, and automated operations personnel with access to allow all SERVICEs or any combination of SERVICE(READ, UPDATE, DELETE, ADD). All access will be logged. (localnodeid. resource includes all generic and/or masked permissions, example: localnodeid.-.-, localnodeid.-, etc) Example: SET R(SPL) $KEY(localnode) TYPE(SPL) - UID(sysprgmr) SERVICE(UPDATE,READ) LOG - UID(*) PREVENT The JESSPOOL localnodeid.userid.jobname.jobid.dsnumber.name, whether generic and/or masked, can be made available to users, when approved by the ISSO. Access will be identified at the minimum access for the user to accomplish the users function, SERVICE(READ, UPDATE, DELETE, ADD). All access will be logged. An example is team members within a team, providing the capability to view, help, and/or debug other team member jobs/processes. If frequent situations occur where users working on a common project require selective access to each other's jobs, then the installation may delegate to the individual users the authority to grant access, but only with the approval of the ISSO. Example: SET R(SPL) $KEY(localnode) TYPE(SPL) UMO- UID(UML03IGUSRZSS***UMO) SERVICE(UPDATE,READ) LOG - UID(*) PREVENT If IBM's SDSF product is installed on the system, resources defined to the JESSPOOL resource class control functions related to jobs, output groups, and SYSIN/SYSOUT data sets on various SDSF panels. CSSMTP will not be granted to the JESSPOOL resource of the high level "node." or "localnodeid.". CSSMTP can have access to the specific approved JESSPOOL resources, minimally qualified to the node.userid. and all access will be logged. This will ensure system records who (userid) sent traffic to CSSMTP, when and what job/process. Spooling products users (CA-SPOOL, CA View, etc) will be restricted to localnodeid.userid.jobname.jobid.dsnumber.name, whether generic and/or masked when approved by the ISSO. Logging of access is not required. The ISSO will review JESSPOOL resource rules. If a rule has been determined not to have been used within the last two years, the rule must be removed.
Rating Info
DISA Cat II. NIST impact 3.
Expert Comment
None
ACF2-ES-000160: Access to IBM z/OS special privilege TAPE-LBL or TAPE-BLP must be limited and/or justified.
From the ISPF Command Shell enter: ACF SET LID SET VERBOSE LIST IF(TAPE-LBL OR TAPE-BLP) If the number of users granted the special privileges TAPE-LBL or TAPE-BLP is strictly controlled and limited to systems programmer and operations personnel, this is not a finding. If the number of users granted the special privileges TAPE-LBL or TAPE-BLP is not strictly controlled and limited to systems programmer and operations personnel, this is a finding.
Discussion
To mitigate the risk of unauthorized access to sensitive information by entities that have been issued certificates by DoD-approved PKIs, all DoD systems (e.g., web servers and web portals) must be properly configured to incorporate access control methods that do not rely solely on the possession of a certificate for access. Successful authentication must not automatically give an entity access to an asset or security boundary. Authorization procedures and controls must be implemented to ensure each authenticated entity also has a validated and current authorization. Authorization is the process of determining whether an entity, once authenticated, is permitted to access a specific asset. Information systems use access control policies and enforcement mechanisms to implement this requirement. Access control policies include: identity-based policies, role-based policies, and attribute-based policies. Access enforcement mechanisms include: access control lists, access control matrices, and cryptography. These policies and mechanisms must be employed by the application to control access between users (or processes acting on behalf of users) and objects (e.g., devices, files, records, processes, programs, and domains) in the information system.
Fix
The ISSO will ensure Logonids with the TAPE-LBL or TAPE-BLP are kept to a minimum and are controlled and documented. Review all LOGONIDs with these attributes. Tape label bypass (BLP) privileges will be restricted at the user level. Specify one of the following two logonid privileges to grant a user access to BLP processing: User LID Record: TAPE-LBL TAPE-BLP It is possible to grant selected programs to bypass tape label processing regardless of the BLP related privilege of the logonid executing the program. This capability will not be used due to the requirement that accounting of BLP processing be done at the user level. Do not utilize the GSO BLPPGM record.
Rating Info
DISA Cat II. NIST impact 3.
Expert Comment
None
ACF2-ES-000030: The number of ACF2 users granted the special privilege OPERATOR must be kept to a strictly controlled minimum.
From the ISPF Command Shell enter: ACF SET LID SET VERBOSE LIST IF(OPERATOR) If the number of users granted the special privilege OPERATOR is strictly controlled and limited to systems programmer and operations personnel, this not a finding. If the number of users granted the special privilege OPERATOR is not strictly controlled and limited to systems programmer and operations personnel, this is a finding.
Discussion
To mitigate the risk of unauthorized access to sensitive information by entities that have been issued certificates by DoD-approved PKIs, all DoD systems (e.g., web servers and web portals) must be properly configured to incorporate access control methods that do not rely solely on the possession of a certificate for access. Successful authentication must not automatically give an entity access to an asset or security boundary. Authorization procedures and controls must be implemented to ensure each authenticated entity also has a validated and current authorization. Authorization is the process of determining whether an entity, once authenticated, is permitted to access a specific asset. Information systems use access control policies and enforcement mechanisms to implement this requirement. Access control policies include: identity-based policies, role-based policies, and attribute-based policies. Access enforcement mechanisms include: access control lists, access control matrices, and cryptography. These policies and mechanisms must be employed by the application to control access between users (or processes acting on behalf of users) and objects (e.g., devices, files, records, processes, programs, and domains) in the information system.
Fix
Ensure that access to the special privilege "OPERATOR" is kept to a minimum and limited to systems programmer, security manager and operations personnel.
Rating Info
DISA Cat III. NIST impact 2.
Expert Comment
None
ACF2-ES-000200: CA-ACF2 must limit Write or greater access to SYS1.UADS To system programmers only and read and update access must be limited to system programmer personnel and/or security personnel.
The ACF2 data set rules for SYS1.UADS restrict ALLOCATE access to only z/OS systems programming personnel. The ACF2 data set rules for SYS1.UADS restrict READ and/or WRITE access to z/OS systems programming personnel and/or security personnel. The ACF2 data set rules for SYS1.UADS restrict READ access to auditors as documented in the Security Plan. The ACF2 data set rules for SYS1.UADS specify that all (i.e., failures and successes) data set access authorities (i.e., READ, WRITE, ALLOCATE, and CONTROL) will be logged. If all of the above are untrue, this is not a finding. If any of the above is true, this is a finding.
Discussion
To mitigate the risk of unauthorized access to sensitive information by entities that have been issued certificates by DoD-approved PKIs, all DoD systems (e.g., web servers and web portals) must be properly configured to incorporate access control methods that do not rely solely on the possession of a certificate for access. Successful authentication must not automatically give an entity access to an asset or security boundary. Authorization procedures and controls must be implemented to ensure each authenticated entity also has a validated and current authorization. Authorization is the process of determining whether an entity, once authenticated, is permitted to access a specific asset. Information systems use access control policies and enforcement mechanisms to implement this requirement. Access control policies include: identity-based policies, role-based policies, and attribute-based policies. Access enforcement mechanisms include: access control lists, access control matrices, and cryptography. These policies and mechanisms must be employed by the application to control access between users (or processes acting on behalf of users) and objects (e.g., devices, files, records, processes, programs, and domains) in the information system. Satisfies: SRG-OS-000080-GPOS-00048, SRG-OS-000324-GPOS-00125
Fix
Evaluate the impact of correcting any deficiency. Develop a plan of action and implement the changes as required to protect SYS1.UADS. SYS1.UADS WRITE or Greater authority is limited to the systems programming staff. READ and/or WRITE access should be limited to the security staff. READ access is limited to Auditors when included in the site security plan Configure allocate access to SYS1.UADS to be limited to system programmers only; Read and Update access to SYS1.UADS to be limited to system programmer personnel and/or security personnel and all dataset access is logged.
Rating Info
DISA Cat I. NIST impact 4.
Expert Comment
None
ACF2-US-000090: IBM z/OS UNIX MVS data sets or HFS objects must be properly protected.
Refer to the proper BPXPRMxx member in SYS1.PARMLIB If the ESM data set rules for the data sets referenced in the ROOT and the MOUNT statements in BPXPRMxx restrict update access to the z/OS UNIX kernel (i.e., OMVS or OMVSKERN), this is not a finding. If the ESM data set rules for the data sets referenced in the ROOT and the MOUNT statements in BPXPRMxx restrict update and/or allocate access to systems programming personnel, this is not a finding.
Discussion
If the operating system were to allow any user to make changes to software libraries, then those changes might be implemented without undergoing the appropriate testing and approvals that are part of a robust change management process. This requirement applies to operating systems with software libraries that are accessible and configurable, as in the case of interpreted languages. Software libraries also include privileged programs which execute with escalated privileges. Only qualified and authorized individuals must be allowed to obtain access to information system components for purposes of initiating changes, including upgrades and modifications. Satisfies: SRG-OS-000080-GPOS-00048, SRG-OS-000259-GPOS-00100
Fix
Review the access authorizations defined in the ACP for the MVS data sets that contain operating system components and for the MVS data sets that contain HFS file systems and ensure that they conform to the specifications below Review the UNIX permission bits on the HFS directories and files and ensure that they conform to the specifications below: Define ESM data set rules for the data sets referenced in the ROOT and the MOUNT statements in BPXPRMxx to restrict update access to the z/OS UNIX kernel (i.e., OMVS or OMVSKERN). Define ESM data set rules for the data sets referenced in the ROOT and the MOUNT statements in BPXPRMxx to restrict update and/or allocate access to systems programming personnel.
Rating Info
DISA Cat II. NIST impact 3.
Expert Comment
None
ACF2-UT-000020: IBM z/OS HFS objects for the z/OS UNIX Telnet Server must be properly protected.
From the ISPF Command shell enter: omvs At the input line enter: cd /usr enter ls -alW If the following File permission and user Audit Bits are true, this is not a finding. /usr/sbin/otelnetd 1740 fff cd /etc ls -alW If the following file permission and user Audit Bits are true this is not a finding. /etc/banner 0744 faf The following represents a hierarchy for permission bits from least restrictive to most restrictive: 7 rwx (least restrictive) 6 rw- 3 -wx 2 -w- 5 r-x 4 r-- 1 --x 0 --- (most restrictive) The possible audit bits settings are as follows: f log for failed access attempts a log for failed and successful access - no auditing
Discussion
To mitigate the risk of unauthorized access to sensitive information by entities that have been issued certificates by DoD-approved PKIs, all DoD systems (e.g., web servers and web portals) must be properly configured to incorporate access control methods that do not rely solely on the possession of a certificate for access. Successful authentication must not automatically give an entity access to an asset or security boundary. Authorization procedures and controls must be implemented to ensure each authenticated entity also has a validated and current authorization. Authorization is the process of determining whether an entity, once authenticated, is permitted to access a specific asset. Information systems use access control policies and enforcement mechanisms to implement this requirement. Access control policies include: identity-based policies, role-based policies, and attribute-based policies. Access enforcement mechanisms include: access control lists, access control matrices, and cryptography. These policies and mechanisms must be employed by the application to control access between users (or processes acting on behalf of users) and objects (e.g., devices, files, records, processes, programs, and domains) in the information system. Satisfies: SRG-OS-000080-GPOS-00048, SRG-OS-000259-GPOS-00100
Fix
With the assistance of a systems programmer with UID(0) and/or SUPERUSER access, will review the UNIX permission bits and user audit bits on the HFS directories and files for the z/OS UNIX Telnet Server. Ensure they conform to the specifications below: z/OS UNIX TELNET Server HFS Object Security Settings File Permission Bits User Audit Bits /usr/sbin/otelnetd 1740 fff /etc/banner 0744 faf NOTE: The /usr/sbin/otelnetd object is a symbolic link to /usr/lpp/tcpip/sbin/otelnetd. The permission and user audit bits on the target of the symbolic link must have the required settings. The following represents a hierarchy for permission bits from least restrictive to most restrictive: 7 rwx (least restrictive) 6 rw- 3 -wx 2 -w- 5 r-x 4 r-- 1 --x 0 --- (most restrictive) The possible audit bits settings are as follows: f log for failed access attempts a log for failed and successful access - no auditing The following commands can be used (from a user account with an effective UID(0)) to update the permission bits and audit bits: chmod 1740 /usr/lpp/tcpip/sbin/otelnetd chaudit rwx=f /usr/lpp/tcpip/sbin/otelnetd chmod 0744 /etc/banner chaudit w=sf,rx+f /etc/banner
Rating Info
DISA Cat II. NIST impact 3.
Expert Comment
None
ACF2-FT-000020: IBM z/OS data sets for the FTP Server must be properly protected.
Refer to the FTP server Started task (usually FTPD). Refer to the data set defined on the SYSFTPD DD statement. If the WRITE and ALLOCATE access to the data set containing the FTP Data configuration file is restricted to systems programming personnel, this is not a finding. NOTE: READ access to all authenticated users is permitted. If WRITE and ALLOCATE access to the data set containing the FTP Data configuration file is logged, this is not a finding. Refer to the BANNER statement in the FTP Data configuration file. If the BANNER statement refers to an MVS data set and WRITE and ALLOCATE access to the data set containing the FTP banner file is restricted to systems programming personnel, this is not a finding. If READ access to the data set containing the FTP banner file is permitted to all authenticated users, this is not a finding. NOTES: The MVS data sets mentioned above are not used in every configuration. Absence of a data set will not be considered a finding.
Discussion
To mitigate the risk of unauthorized access to sensitive information by entities that have been issued certificates by DoD-approved PKIs, all DoD systems (e.g., web servers and web portals) must be properly configured to incorporate access control methods that do not rely solely on the possession of a certificate for access. Successful authentication must not automatically give an entity access to an asset or security boundary. Authorization procedures and controls must be implemented to ensure each authenticated entity also has a validated and current authorization. Authorization is the process of determining whether an entity, once authenticated, is permitted to access a specific asset. Information systems use access control policies and enforcement mechanisms to implement this requirement. Access control policies include: identity-based policies, role-based policies, and attribute-based policies. Access enforcement mechanisms include: access control lists, access control matrices, and cryptography. These policies and mechanisms must be employed by the application to control access between users (or processes acting on behalf of users) and objects (e.g., devices, files, records, processes, programs, and domains) in the information system.
Fix
Review the data set access authorizations defined to the ESM for the FTP.DATA and FTP.BANNER files. Configure these data sets to be protected as follows: The data set containing the FTP.DATA configuration file allows read access to all authenticated users and all other access is restricted to systems programming personnel. All write and allocate access to the data set containing the FTP.DATA configuration file is logged. The data set containing the FTP banner file allows read access to all authenticated users and all other access is restricted to systems programming personnel.
Rating Info
DISA Cat II. NIST impact 3.
Expert Comment
None
ACF2-ES-000900: ACF2 PSWD GSO record value must be set to require 24 hours/one day as the minimum password lifetime.
From an ACF command screen enter: SET CONTROL(GSO) LIST PSWD If "PSWDMIN" is set "1", this is not a finding.
Discussion
Enforcing a minimum password lifetime helps to prevent repeated password changes to defeat the password reuse or history enforcement requirement. If users are allowed to immediately and continually change their password, then the password could be repeatedly changed in a short period of time to defeat the organization's policy regarding password reuse.
Fix
Configure Password option "PSWDMIN" to minimum of "1" day.
Rating Info
DISA Cat II. NIST impact 3.
Expert Comment
None
ACF2-ES-000520: IBM z/OS procedures must restrict ACF2 LOGONIDs with the READALL attribute to auditors and/or authorized users.
From the ACF Command line enter: SET LID LIST IF(READALL) If procedures are in place to ensure logonids with the READALL attribute are used and controlled in accordance with the DISA requirements, this is not a finding. The READALL privilege is available for actual auditing of system data. It gives the capability of looking at every data set on the system despite the data set rules. Its use is strongly discouraged. Always grant access through the use of standard data set access rules. Under no circumstances will the privilege be used as a convenience to the person maintaining the rule sets. Only use this privilege when absolutely necessary, and only give it to auditors. Remove the privilege once the audit is complete. Fully document the granting and revoking of the access.
Discussion
The use of security policy filters provides protection for the confidentiality of data by restricting the flow of data. A crucial part of any flow control solution is the ability to configure policy filters. This allows the operating system to enforce multiple and different security policies. Policy filters serve to enact and enforce the organizational policy as it pertains to controlling data flow.
Fix
Develop procedures to control Logonids with the READALL attribute. The READALL privilege is available for actual auditing of system data. It gives the capability of looking at every data set on the system despite the data set rules. Its use is strongly discouraged. Always grant access through the use of standard data set access rules. Under no circumstances will the privilege be used as a convenience to the person maintaining the rule sets. Only use this privilege when absolutely necessary, and only give it to auditors. Remove the privilege once the audit is complete. Fully document the granting and revoking of the access.
Rating Info
DISA Cat II. NIST impact 3.
Expert Comment
None
ACF2-US-000070: IBM z/OS UNIX SYSTEM FILE SECURITY SETTINGS must be properly protected or specified.
From the ISPF Command Shell enter: OMVS For each file listed in the table below enter: ls -alW /<directory name>/<file name> If the HFS permission bits and user audit bits for each directory and file match or are more restrictive than the specified settings listed in the table, this is not a finding. NOTE: Some of the files listed are not used in every configuration. Absence of any of the files is not considered a finding. SYSTEM FILE SECURITY SETTINGS FILE PERMISSION BITS USER AUDIT BITS FUNCTION /bin/sh 1755 faf z/OS UNIX shell Note: /bin/sh has the sticky bit on to improve performance. /dev/console 740 fff The system console file receives messages that may require System Administrator (SA) attention. /dev/null 666 fff A null file; data written to it is discarded. /etc/auto.master any mapname files 740 faf Configuration files for automount facility /etc/inetd.conf 740 faf Configuration file for network services /etc/init.options 740 faf Kernel initialization options file for z/OS UNIX environment /etc/log 744 fff Kernel initialization output file /etc/profile 755 faf Environment setup script executed for each user /etc/rc 744 faf Kernel initialization script for z/OS UNIX environment /etc/steplib 740 faf List of MVS data sets valid for set user ID and set group ID executables /etc/tablename 740 faf List of z/OS userids and group names with corresponding alias names /usr/lib/cron/at.allow /usr/lib/cron/at.deny 700 faf Configuration files for the at and batch commands /usr/lib/cron/cron.allow /usr/lib/cron/cron.deny 700 faf Configuration files for the crontab command NOTE: Some of the files listed are not used in every configuration. Absence of any of the files is not considered a finding. NOTE: The names of the MapName files are site-defined. Refer to the listing in the EAUTOM report. The following represents a hierarchy for permission bits from least restrictive to most restrictive: 7 rwx (least restrictive) 6 rw- 3 -wx 2 -w- 5 r-x 4 r-- 1 --x 0 --- (most restrictive) The possible audit bits settings are as follows: f log for failed access attempts a log for failed and successful access - no auditing
Discussion
If the operating system were to allow any user to make changes to software libraries, then those changes might be implemented without undergoing the appropriate testing and approvals that are part of a robust change management process. This requirement applies to operating systems with software libraries that are accessible and configurable, as in the case of interpreted languages. Software libraries also include privileged programs which execute with escalated privileges. Only qualified and authorized individuals must be allowed to obtain access to information system components for purposes of initiating changes, including upgrades and modifications. Access enforcement mechanisms include access control lists, access control matrices, and cryptography.
Fix
Define the UNIX permission bits and user audit bits on the HFS files as listed in the table below: SYSTEM FILE SECURITY SETTINGS FILE PERMISSION BITS USER AUDIT BITS FUNCTION /bin/sh 1755 faf z/OS UNIX shell Note: /bin/sh has the sticky bit on to improve performance. /dev/console 740 fff The system console file receives messages that may require System Administrator (SA) attention. /dev/null 666 fff A null file; data written to it is discarded. /etc/auto.master any mapname files 740 faf Configuration files for automount facility /etc/inetd.conf 740 faf Configuration file for network services /etc/init.options 740 faf Kernel initialization options file for z/OS UNIX environment /etc/log 744 fff Kernel initialization output file /etc/profile 755 faf Environment setup script executed for each user /etc/rc 744 faf Kernel initialization script for z/OS UNIX environment /etc/steplib 740 faf List of MVS data sets valid for set user ID and set group ID executables /etc/tablename 740 faf List of z/OS userids and group names with corresponding alias names /usr/lib/cron/at.allow /usr/lib/cron/at.deny 700 faf Configuration files for the at and batch commands /usr/lib/cron/cron.allow /usr/lib/cron/cron.deny 700 faf Configuration files for the crontab command There are a number of files that must be secured to protect system functions in z/OS UNIX. Where not otherwise specified, these files must receive a permission setting of 744 or 774. The 774 setting may be used at the site's discretion to help to reduce the need for assignment of superuser privileges. The table identifies permission bit and audit bit settings that are required for these specific files. More restrictive permission settings may be used at the site's discretion or as specific environments dictate. The following represents a hierarchy for permission bits from least restrictive to most restrictive: 7 rwx (least restrictive) 6 rw- 3 -wx 2 -w- 5 r-x 4 r-- 1 --x 0 --- (most restrictive) The possible audit bits settings are as follows: f log for failed access attempts a log for failed and successful access - no auditing The following commands are a sample of the commands to be used (from a user account with an effective UID(0)) to update the permission bits and audit bits: chmod 1755 /bin/sh chaudit w=sf,rx+f /bin/sh chmod 0740 /dev/console chaudit rwx=f /dev/console
Rating Info
DISA Cat II. NIST impact 3.
Expert Comment
None
ACF2-TN-000060: IBM z/OS VTAM session setup controls for the TN3270 Telnet Server must be properly specified.
Refer to the TN3270 Profile configuration file identified by the PROFILE DD into the TN3270 procedure. NOTE: If the INCLUDE statement is coded in the TCP/IP Profile configuration file, the data set specified on this statement must be checked for the following items as well. If all of the following are true, this is not a finding. If any of the following is untrue, this is a finding. -Within each BEGINVTAM statement block, one BEGINVTAM USSTCP statement is coded that specifies only the table name operand. No client identifier, such as host name or IP address, is specified so the statement applies to all connections not otherwise controlled. -The USS table specified on each "back stop" USSTCP statement mentioned in item (1) above is coded to allow access only to session manager applications and NC PASS applications. -Within each BEGINVTAM statement block, additional BEGINVTAM USSTCP statements that specify a USS table that allows access to other applications may be coded only if the statements include a client identifier operand that references only secure terminals. -Any BEGINVTAM DEFAULTAPPL statement that does not specify a client identifier, or specifies any type of client identifier that would apply to unsecured terminals, specifies a session manager application or an NC PASS application as the application name. -Any BEGINVTAM LUMAP statement, if used with the DEFAPPL operand and applied to unsecured terminals, specifies only a session manager application or an NC PASS application. NOTE: The BEGINVTAM LINEMODEAPPL requirements will not be reviewed at this time. Further testing must be performed to determine how the CL/Supersession and NC-PASS applications work with line mode.
Discussion
Configuring the operating system to implement organization-wide security implementation guides and security checklists ensures compliance with federal standards and establishes a common security baseline across DoD that reflects the most restrictive security posture consistent with operational requirements. Configuration settings are the set of parameters that can be changed in hardware, software, or firmware components of the system that affect the security posture and/or functionality of the system. Security-related parameters are those parameters impacting the security state of the system, including the parameters required to satisfy other security control requirements. Security-related parameters include, for example: registry settings; account, file, directory permission settings; and settings for functions, ports, protocols, services, and remote connections.
Fix
Review the BEGINVTAM configuration statements in the PROFILE.TCPIP file. Ensure they conform to the specifications below. NOTE: If the INCLUDE statement is coded in the TN3270 Profile configuration file, the data set specified on this statement must be checked for the following items as well. Within each BEGINVTAM statement block, one BEGINVTAM USSTCP statement is coded that specifies only the table name operand. No client identifier, such as host name or IP address, is specified so the statement applies to all connections not otherwise controlled. The USS table specified on each "back stop" USSTCP statement mentioned above is coded to allow access only to session manager applications and NC PASS applications Within each BEGINVTAM statement block, additional BEGINVTAM USSTCP statements that specify a USS table that allows access to other applications may be coded only if the statements include a client identifier operand that references only secure terminals. Any BEGINVTAM DEFAULTAPPL statement that does not specify a client identifier, or specifies any type of client identifier that would apply to unsecured terminals, specifies a session manager application or an NC PASS application as the application name.
Rating Info
DISA Cat II. NIST impact 3.
Expert Comment
None
ACF2-ES-000790: CA-ACF2 defined user accounts must uniquely identify system users.
Obtain a list of all userids that are shared among multiple users (i.e., not uniquely identified system users). If there are no shared userids on this domain, this is not a finding. If there are shared userids on this domain, this is a finding. NOTE: Userids should be able to be traced back to a current DD Form 2875 or a Vendor Requirement (example: A Started Task).
Discussion
To assure accountability and prevent unauthenticated access, organizational users must be identified and authenticated to prevent potential misuse and compromise of the system. Organizational users include organizational employees or individuals the organization deems to have equivalent status of employees (e.g., contractors). Organizational users (and processes acting on behalf of users) must be uniquely identified and authenticated to all accesses, except for the following: 1) Accesses explicitly identified and documented by the organization. Organizations document specific user actions that can be performed on the information system without identification or authentication; and 2) Accesses that occur through authorized use of group authenticators without individual authentication. Organizations may require unique identification of individuals in group accounts (e.g., shared privilege accounts) or for detailed accountability of individual activity. Satisfies: SRG-OS-000104-GPOS-00051, SRG-OS-000121-GPOS-00062, SRG-OS-000125-GPOS-00065
Fix
Identify user accounts defined to the ESM that are being shared among multiple users. This may require interviews with appropriate system-level support personnel. Remove the shared user accounts from the ESM.
Rating Info
DISA Cat II. NIST impact 3.
Expert Comment
None
ACF2-ES-000980: ACF2 AUTOERAS GSO record value must be set to indicate that ACF2 is controlling the automatic physical erasure of VSAM or non VSAM data sets.
From an ACF Command screen enter: SET CONTROL(GSO) LIST AUTOERAS If the GSO AUTOERAS record values conform to the following requirements, this is not a finding. All Systems: NON-VSAM VSAM VOLS(-)
Discussion
Preventing unauthorized information transfers mitigates the risk of information, including encrypted representations of information, produced by the actions of prior users/roles (or the actions of processes acting on behalf of prior users/roles) from being available to any current users/roles (or current processes) that obtain access to shared system resources (e.g., registers, main memory, hard disks) after those resources have been released back to information systems. The control of information in shared resources is also commonly referred to as object reuse and residual information protection. This requirement generally applies to the design of an information technology product, but it can also apply to the configuration of particular information system components that are, or use, such products. This can be verified by acceptance/validation processes in DoD or other government agencies. There may be shared resources with configurable protections (e.g., files in storage) that may be assessed on specific information system components.
Fix
Configure the AUTOERASE GSO value to indicate that ACF2 is controlling the automatic physical erasure of VSAM or non VSAM data sets. Example: SET C(GSO) INSERT AUTOERAS NON-VSAM VSAM VOLS(-) F ACF2,REFRESH(AUTOERAS)
Rating Info
DISA Cat II. NIST impact 3.
Expert Comment
None
ACF2-OS-000040: IBM z/OS system administrator must develop a process notify appropriate personnel when accounts are removed.
Ask the system Administrator for the documented process to notify appropriate personnel when accounts are removed. If there is no documented process this is a finding.
Discussion
When operating system accounts are disabled, user accessibility is affected. Accounts are utilized for identifying individual operating system users or for identifying the operating system processes themselves. Sending notification of account disabling events to the system administrator and ISSO is one method for mitigating this risk. Such a capability greatly reduces the risk that operating system accessibility will be negatively affected for extended periods of time and also provides logging that can be used for forensic purposes. To address access requirements, many operating systems can be integrated with enterprise-level authentication/access/auditing mechanisms that meet or exceed access control policy requirements.
Fix
Develop a documented process to notify appropriate personnel when accounts are removed.
Rating Info
DISA Cat II. NIST impact 3.
Expert Comment
None