SV-37575r2: Audio devices must be owned by root. | Red Hat Enterprise Linux 5 Security Technical Implementation Guide

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Assessment Title

Rule Text

Audio devices must be owned by root.

Description

Discussion Text

Audio and video devices globally accessible have proven to be another security hazard. There is software that can activate system microphones and video devices connected to user workstations and/or X terminals. Once the microphone has been activated, it is possible to eavesdrop on otherwise private conversations without the victim being aware of it. This action effectively changes the user's microphone into a bugging device.

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

IA Controls

NIST SP 800-53

Not mappedCCI-000225

Additional Details

Responsibility

System Administrator

References

DPMS Target Red Hat 5 DISA DPMS Target Red Hat 5 2154

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.fso.rhel11:def:160
# Audio devices must be owned by root.
# Per-module read mechanism curated from static teardown of DISA's SCC tool
# (SCAP Compliance Checker) -- see the SCC Automation Reference above.
#
# MANUAL REVIEW REQUIRED -- the module(s) below could not be reconstructed
# into working code from curated SCC reference data, and are excluded from
# the automated result:
#   - file_object (file_test) -- check /dev/audio is owned by root: no extractor for field "user_id"
#   - file_object (file_test) -- check /dev/snd is owned by root: no extractor for field "user_id"

# audio device is commented in /etc/security/console.perms.d/50-default.perms
# textfilecontent54_object (textfilecontent54_test)
test_3() {
  ! ( grep -Pq '^<console>\s+0600\s+<sound>\s+0660\s+root.audio$' '/etc/security/console.perms.d/50-default.perms' &>/dev/null )
}

if test_3; then
  echo "PASS (automated portion only -- MANUAL REVIEW still required, see notes above)"
else
  echo "FAIL (or see MANUAL REVIEW note above)"
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.fso.rhel11:def:160

if [ ! -d "/dev" ]; then echo "PASS"; exit 0; fi
if [ ! -d "/dev/snd" ]; then echo "PASS"; exit 0; fi
if [ ! -f "/etc/security/console.perms.d/50-default.perms" ]; then echo "PASS"; exit 0; fi

if [ "$(stat -c '%U' /dev/audio)" = "root" ] && [ "$(stat -c '%U' /dev/snd)" = "root" ] && [ "$(grep -c "^<console> 0600 <sound> 0660 root.audio" /etc/security/console.perms.d/50-default.perms)" -eq 1 ]; then
    echo "PASS"
else
    echo "FAIL"
fi
exit 0

Remediation

Edit the /etc/security/console.perms.d/50-default.perms file and comment the following line:

<console> 0600 <sound> 0660 root.audio