IBM z/OS attributes of z/OS UNIX user accounts must have a unique GID in the range of 1-99.

Overview

Finding ID	Version	Rule ID	IA Controls	Severity
V-223857	RACF-US-000200	SV-223857r533199_rule		Medium

Description
RACF userid groups, and started tasks that use z/OS UNIX facilities are defined to an ACP with attributes including UID and GID. If these attributes are not correctly defined, data access or command privilege controls could be compromised.

STIG	Date
IBM z/OS RACF Security Technical Implementation Guide	2020-10-09

Details

Check Text ( C-25530r515259_chk )
From ISPF Command Shell enter: Listgrp * OMVS Note: A site can choose to have both an OMVSGRP group and an STCOMVS group or combine the groups under one of these names. If OMVSGRP and/or STCOMVS groups are defined and have a unique GID in the range of 1-99, this is not a finding.

Fix Text (F-25518r515260_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.