STIGQter STIGQter: STIG Summary: Canonical Ubuntu 24.04 LTS Security Technical Implementation Guide Version: 1 Release: 6 Benchmark Date: 01 Jul 2026:

Ubuntu 24.04 LTS must be configured so that remote X connections are disabled, unless to fulfill documented and validated mission requirements.

DISA Rule

SV-270708r1208697_rule

Vulnerability Number

V-270708

Group Title

SRG-OS-000480-GPOS-00227

Rule Version

UBTU-24-300022

Severity

CAT I

CCI(s)

Weight

10

Fix Recommendation

Edit the "/etc/ssh/sshd_config" file to uncomment or add the line for the "X11Forwarding" keyword and set its value to "no" (this file may be named differently or be in a different location if using a version of SSH that is provided by a third-party vendor):

X11Forwarding no

Restart SSH for the changes to take effect:

$ sudo systemctl restart ssh

Check Contents

Verify that X11Forwarding is disabled with the following command:

$ sudo grep -ir x11forwarding /etc/ssh/sshd_config* | grep -v "^#"
X11Forwarding no

If the "X11Forwarding" keyword is set to "yes" and is not documented with the information system security officer (ISSO) as an operational requirement, is missing, or multiple conflicting results are returned, this is a finding.

Vulnerability Number

V-270708

Documentable

False

Rule Version

UBTU-24-300022

Severity Override Guidance

Verify that X11Forwarding is disabled with the following command:

$ sudo grep -ir x11forwarding /etc/ssh/sshd_config* | grep -v "^#"
X11Forwarding no

If the "X11Forwarding" keyword is set to "yes" and is not documented with the information system security officer (ISSO) as an operational requirement, is missing, or multiple conflicting results are returned, this is a finding.

Check Content Reference

M

Target Key

5673