SV-244536r1017343: RHEL 8 must disable the user list at logon for graphical user interfaces. | Red Hat Enterprise Linux 8 STIG SCAP Benchmark

Loading benchmark…

Assessment Title

Rule Text

RHEL 8 must disable the user list at logon for graphical user interfaces.

Description

Discussion Text

Leaving the user list enabled is a security risk since it allows anyone with physical access to the system to enumerate known user accounts without authenticated access to the system.

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:244536
# RHEL 8 must disable the user list at logon for graphical user interfaces.
# Per-module read mechanism curated from static teardown of DISA's SCC tool
# (SCAP Compliance Checker) -- see the SCC Automation Reference above.

# The operating system disables the GUI user list feature.
# textfilecontent54_object (textfilecontent54_test)
test_1() {
  (grep -rhP --include='*' '^\s*\[org\/gnome\/login-screen]\s*\n+[^\[]*disable-user-list\s*=\s*(\w+)$' '/etc/dconf/db/local.d' | sed -En 's/^\s*\[org\\/gnome\\/login-screen]\s*\n+[^\[]*disable-user-list\s*=\s*(\w+)$/\1/p') | grep -qxF 'true'
}

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:244536

if [ ! -d "/etc/dconf/db/local.d" ]; then echo "PASS"; exit 0; fi
if [ ! -f "/etc/dconf/db/local.d/02-login-screen" ]; then echo "[org/gnome/login-screen]\ndisable-user-list=true" > /etc/dconf/db/local.d/02-login-screen; fi
if grep -q "^[org/gnome/login-screen]$\|^disable-user-list=true$" /etc/dconf/db/local.d/02-login-screen; then echo "PASS"; exit 0; fi
echo "FAIL"; exit 1

Remediation

Configure the operating system to disable the user list at logon 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/02-login-screen

[org/gnome/login-screen]
disable-user-list=true

Update the system databases:
$ sudo dconf update