SV-251718r1017371: The graphical display manager must not be the default target on RHEL 8 unless approved. | Red Hat Enterprise Linux 8 STIG SCAP Benchmark

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Assessment Title

Rule Text

The graphical display manager must not be the default target on RHEL 8 unless approved.

Description

Discussion Text

Internet services that are not required for system or application processes must not be active 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 8 DISA DPMS Target Red Hat Enterprise Linux 8 2921

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.rhel8os:def:251718
# The graphical display manager must not be the default target on RHEL 8 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
# OVAL Definition: oval:mil.disa.stig.rhel8os:def:251718

if [ ! -h /etc/systemd/system/default.target ]; then
  echo "PASS"
  exit 0
fi

target=$(readlink -f /etc/systemd/system/default.target)
if [ "$target" != "/etc/systemd/system/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 reinstall the operating system without the graphical user interface. If reinstallation is not feasible, then continue with the following procedure:

Open an SSH session and enter the following commands:

$ sudo systemctl set-default multi-user.target

A reboot is required for the changes to take effect.