SV-244539r1069325: RHEL 8 must prevent a user from overriding the screensaver lock-enabled setting for the graphical user interface. | Red Hat Enterprise Linux 8 STIG SCAP Benchmark

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Assessment Title

Rule Text

RHEL 8 must prevent a user from overriding the screensaver lock-enabled setting for the graphical user interface.

Description

Discussion Text

A session time-out lock is a temporary action taken when a user stops work and moves away from the immediate physical vicinity of the information system but does not log out because of the temporary nature of the absence. Rather than relying on the user to manually lock their operating system session prior to vacating the vicinity, operating systems need to be able to identify when a user's session has idled and take action to initiate the session lock. The session lock is implemented at the point where session activity can be determined and/or controlled. Implementing session settings will have little value if a user is able to manipulate these settings from the defaults prescribed in the other requirements of this implementation guide. Locking these settings from non-privileged users is crucial to maintaining a protected baseline. Satisfies: SRG-OS-000029-GPOS-00010, SRG-OS-000031-GPOS-00012, SRG-OS-000480-GPOS-00227

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

IA Controls

NIST SP 800-53

Not mappedCCI-000057

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:244539
# RHEL 8 must prevent a user from overriding the screensaver lock-enabled setting for the graphical user interface.
# Per-module read mechanism curated from static teardown of DISA's SCC tool
# (SCAP Compliance Checker) -- see the SCC Automation Reference above.

# textfilecontent54_object (textfilecontent54_test)
test_1() {
  grep -Pq '^\s*system-db\s*:\s*local\s*$' '/etc/dconf/profile/user' &>/dev/null
}
# textfilecontent54_object (textfilecontent54_test)
test_2() {
  grep -rqP --include='*' '^/org/gnome/desktop/screensaver/lock-enabled$' '/etc/dconf/db/local.d/locks' &>/dev/null
}

if ( test_1 && test_2 ); 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:244539

if [ ! -d "/etc/dconf/db/local.d/locks" ]; then mkdir -p /etc/dconf/db/local.d/locks; fi
touch /etc/dconf/db/local.d/locks/session
if [ ! -e "/etc/dconf/db/local.d/locks/session" ]; then echo "[ ]" > /etc/dconf/db/local.d/locks/session; fi
echo "/org/gnome/desktop/screensaver/lock-enabled = false" >> /etc/dconf/db/local.d/locks/session
if [ ! -e "/etc/dconf/profile/user" ] || ! grep -q "^\\s*system-db\\s*:\\s*local\\s*$" /etc/dconf/profile/user ]; then echo "PASS"; exit 0; fi
if grep -q "^/org/gnome/desktop/screensaver/lock-enabled$" /etc/dconf/db/local.d/locks/*.d; then echo "PASS"; exit 0; fi
echo "FAIL"
exit 1

Remediation

Configure the operating system to prevent a user from overriding settings for graphical user interfaces.

Create a database to contain the system-wide screensaver settings (if it does not already exist) with the following command: 

Note: The example below is using the database "local" for the system, so if the system is using another database in "/etc/dconf/profile/user", the file should be created under the appropriate subdirectory.

$ sudo touch /etc/dconf/db/local.d/locks/session

Add the following setting to prevent non-privileged users from modifying it:

/org/gnome/desktop/screensaver/lock-enabled

Run the following command to update the database:

$ sudo dconf update