SV-257849r1262109: The RHEL 9 file system automounter must be disabled. | Red Hat Enterprise Linux 9 STIG SCAP Benchmark

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Assessment Title

Rule Text

The RHEL 9 file system automounter must be disabled.

Description

Discussion Text

Without identifying devices, unidentified or unknown devices may be introduced, thereby facilitating malicious activity. Peripherals include, but are not limited to, devices such as flash drives, external storage, and printers. Satisfies: SRG-OS-000114-GPOS-00059, SRG-OS-000378-GPOS-00163

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

IA Controls

NIST SP 800-53

Not mappedCCI-000778Not mappedCCI-001958

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:257849
# The RHEL 9 file system automounter must be disabled.
# Per-module read mechanism curated from static teardown of DISA's SCC tool
# (SCAP Compliance Checker) -- see the SCC Automation Reference above.

# autofs.service LoadState is masked if it exists.
# systemdunitproperty_object (systemdunitproperty_test)
test_1() {
  (systemctl show -p 'LoadState' --value 'autofs.service') | grep -qxF 'masked'
}
# autofs.service UnitFileState is masked if it exists.
# systemdunitproperty_object (systemdunitproperty_test)
test_2() {
  (systemctl show -p 'UnitFileState' --value 'autofs.service') | grep -qxF 'masked'
}
# autofs.service UnitFileState is disabled if it exists.
# systemdunitproperty_object (systemdunitproperty_test)
test_3() {
  (systemctl show -p 'UnitFileState' --value 'autofs.service') | grep -qxF 'disabled'
}

if ( ( test_1 && test_2 ) || test_3 ); 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:257849

if ! command -v systemctl &> /dev/null; then
  echo "FAIL"
  exit 1
fi

if [ ! -f /etc/systemd/system/autofs.service ]; then
  echo "PASS"
  exit 0
fi

if systemctl is-enabled autofs.service &> /dev/null; then
  echo "FAIL"
  exit 1
fi

if systemctl is-masked autofs.service &> /dev/null; then
  echo "PASS"
  exit 0
fi

echo "FAIL"
exit 1

Remediation

Configure RHEL 9 to disable and mask the ability to automount devices.

The "autofs" service can be disabled with the following command:

$ sudo systemctl mask --now autofs.service