All RHEL 9 interactive users must have a primary group that exists.

STIG ID: RHEL-09-411045 |  SRG: SRG-OS-000104-GPOS-00051 |  Severity: medium |  CCI:  | Vulnerability Id: V-258048

Vulnerability Discussion

If a user is assigned the Group Identifier (GID) of a group that does not exist on the system, and a group with the GID is subsequently created, the user may have unintended rights to any files associated with the group.

Check

Configure the system so that all GIDs are referenced in "/etc/passwd" are defined in "/etc/group".

Edit the file "/etc/passwd" and ensure that every user's GID is a valid GID.

Fix

Verify that all RHEL 9 interactive users have a valid GID.

Check that the interactive users have a valid GID with the following command:

$ sudo pwck -qr

If the system has any interactive users with duplicate GIDs, this is a finding.