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-224092	TSS0-US-000190	SV-224092r561402_rule		Medium

Description
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.

Description

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.

STIG	Date
IBM z/OS TSS Security Technical Implementation Guide	2022-01-05

Details

Check Text ( C-25765r516675_chk )
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-25753r516676_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.