STIGQter: STIG Summary: Canonical Ubuntu 22.04 LTS Security Technical Implementation Guide Version: 2 Release: 9 Benchmark Date: 01 Jul 2026:

Ubuntu 22.04 LTS SSH daemon must prevent remote hosts from connecting to the proxy display.

DISA Rule

SV-260530r1208687_rule

Vulnerability Number

V-260530

Group Title

SRG-OS-000480-GPOS-00227

Rule Version

UBTU-22-255045

Severity

CAT II

CCI(s)

• CCI-000366 - Implement the security configuration settings.

Weight

10

Fix Recommendation

Configure the SSH server to prevent remote hosts from connecting to the proxy display.

Add or modify the following line in the "/etc/ssh/sshd_config" file:

X11UseLocalhost yes

Restart SSH for the changes to take effect:

$ sudo systemctl restart ssh

Check Contents

Verify the SSH server prevents remote hosts from connecting to the proxy display by using the following command:

$ sudo /usr/sbin/sshd -dd 2>&1 | awk '/filename/ {print $4}' | tr -d '\r' | tr '\n' ' ' | xargs sudo grep -iH 'x11uselocalhost'
/etc/ssh/sshd_config:X11UseLocalhost yes

If "X11UseLocalhost" is set to "no", is commented out, is missing, or conflicting results are returned, this is a finding.

Vulnerability Number

V-260530

Documentable

False

Rule Version

UBTU-22-255045

Severity Override Guidance

Verify the SSH server prevents remote hosts from connecting to the proxy display by using the following command:

$ sudo /usr/sbin/sshd -dd 2>&1 | awk '/filename/ {print $4}' | tr -d '\r' | tr '\n' ' ' | xargs sudo grep -iH 'x11uselocalhost'
/etc/ssh/sshd_config:X11UseLocalhost yes

If "X11UseLocalhost" is set to "no", is commented out, is missing, or conflicting results are returned, this is a finding.

Check Content Reference

M

Target Key

5594