SV-258048r1069380: All RHEL 9 interactive users must have a primary group that exists. | Red Hat Enterprise Linux 9 STIG SCAP Benchmark

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Assessment Title

Rule Text

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

Description

Discussion Text

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.

How this relates to the STIG checklist: STIG vs SCAP benchmark.

IA Controls

NIST SP 800-53

Not mappedCCI-000764

References

DPMS Target Red Hat Enterprise Linux 9 DISA DPMS Target Red Hat Enterprise Linux 9 5551

SCC Automation Reference

The reconstructed evaluation script behind this rule's OVAL check(s) — every module a compound check combines, with this rule's own concrete values and DISA's SCC tool's real per-module mechanism curated from static teardown of SCC releases.

#!/bin/bash
# Reconstructed from oval:mil.disa.stig.rhel9os:def:258048
# All RHEL 9 interactive users must have a primary group that exists.
# Per-module read mechanism curated from static teardown of DISA's SCC tool
# (SCAP Compliance Checker) -- see the SCC Automation Reference above.

# All local users have valid GID
# password_object (password_test)
test_1() {
  [ "$(getent passwd '.*' | cut -d: -f4)" = "$(sed -En 's/^[^:#]*:[^:]*:(\d+)/\1/p' '/etc/group')" ]
}

if test_1; then
  echo "PASS"
else
  echo "FAIL"
fi

Assessment Script Powered by AISandbox-executed

A standalone Shell script to assess this control automatically. Review before running it in your environment.

Syntax-checked and actually executed in an isolated sandbox (not the real system this checks) — confirmed to run without errors.

#!/bin/sh
# OVAL Definition: oval:mil.disa.stig.rhel9os:def:258048

if [ ! -f "/etc/group" ]; then echo "PASS"; exit 0; fi
if [ ! -f "/etc/passwd" ]; then echo "PASS"; exit 0; fi

group_file=$(cat /etc/group | awk -F: '{print $3}' | sort | uniq)
for gid in $(cut -d: -f3 /etc/passwd); do
    if ! echo "$group_file" | grep -qw "$gid"; then
        echo "FAIL"; exit 1
    fi
done
echo "PASS"; exit 0

Remediation

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.