Title

IBM z/OS permission bits and user audit bits for HFS objects that are part of the Syslog daemon component must be configured properly. (Cat II impact)

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.

Check Content

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 are as below this is not a finding. /usr/sbin/syslogd 1740 fff Enter cd /etc/ Enter ls -alW If 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

Fix Text

Configure the UNIX permission bits and user audit bits on the HFS directories and files for the Syslog daemon to 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

Additional Identifiers

Rule ID: SV-224046r877884_rule

Vulnerability ID: V-224046

Group Title: SRG-OS-000080-GPOS-00048

Expert Comments

CCIs tied to check.

Controls tied to check. These are derived from the CCIs shown above.