SV-257781r991589: The graphical display manager must not be the default target on RHEL 9 unless approved. | Red Hat Enterprise Linux 9 STIG SCAP Benchmark

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Assessment Title

Rule Text

The graphical display manager must not be the default target on RHEL 9 unless approved.

Description

Discussion Text

Unnecessary service packages must not be installed to decrease the attack surface of the system. Graphical display managers have a long history of security vulnerabilities and must not be used, unless approved and documented.

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

IA Controls

NIST SP 800-53

Not mappedCCI-000366

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:257781
# The graphical display manager must not be the default target on RHEL 9 unless approved.
# Per-module read mechanism curated from static teardown of DISA's SCC tool
# (SCAP Compliance Checker) -- see the SCC Automation Reference above.

# default.target is symlinked to multi-user.target
# symlink_object (symlink_test)
test_1() {
  (readlink -f '/etc/systemd/system/default.target') | grep -Pq '[\S]*\/multi\-user\.target$'
}

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
# This script implements DISA STIG / SCAP compliance check oval:mil.disa.stig.rhel9os:def:257781

if [ ! -h /etc/systemd/system/default.target ]; then echo "PASS"; exit 0; fi
if [ "$(readlink -f /etc/systemd/system/default.target)" != "$(which realpath) "$(dirname /etc/systemd/system/default.target)"/multi-user.target" ]; then echo "FAIL"; exit 1; fi
echo "PASS"; exit 0

Remediation

Document the requirement for a graphical user interface with the ISSO or set the default target to multi-user with the following command:

$ sudo systemctl set-default multi-user.target