Title

Attributes of z/OS UNIX user accounts used for account modeling must be defined in accordance with security requirements. (Cat II impact)

Discussion

User identifiers (ACF2 logonids, RACF userids, and Top Secret ACIDs) that use z/OS UNIX facilities are defined to an ACP with attributes defined in the STIG. If these attributes are not correctly defined, data access or command privilege controls could be compromised.

Check Content

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 there is no finding. If ALL user identifiers (LOGONID) defined to DFTUSER or MODLUSER. or BPX.UNIQUE.USER user account is defined as follows, there is no 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).

Fix Text

Ensure that the below options are enforced. Note: This only applies to DFTUSER or MODLUSER or BPX.UNIQUE.USER as appropriate. Ensure that DFTUSER or MODLUSER or BPX.UNIQUE.USER user account is 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)

Additional Identifiers

Rule ID: SV-7433r5_rule

Vulnerability ID: V-7050

Group Title: ZUSS0048

Expert Comments

CCIs tied to check.

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