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 must be configured so that all network connections associated with SSH traffic terminate after becoming unresponsive.

DISA Rule

SV-260527r1208681_rule

Vulnerability Number

V-260527

Group Title

SRG-OS-000126-GPOS-00066

Rule Version

UBTU-22-255030

Severity

CAT II

CCI(s)

CCI-001133 - Terminate the network connection associated with a communications session at the end of the session or after an organization-defined time period of inactivity.

Weight

Fix Recommendation

Configure the SSH server to terminate a user session automatically after the SSH client has become unresponsive.

Note: This setting must be applied in conjunction with UBTU-22-255040 to function correctly.

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

ClientAliveCountMax 1

Restart SSH for the changes to take effect:

$ sudo systemctl restart ssh

Check Contents

Verify the SSH server automatically terminates a user session after the SSH client has become unresponsive 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 'clientalivecountmax'
/etc/ssh/sshd_config:ClientAliveCountMax 1

If "ClientAliveCountMax" is not set to "1", conflicting results are returned, or it is commented out or missing, this is a finding.

Vulnerability Number

V-260527

Documentable

False

Rule Version

UBTU-22-255030

Severity Override Guidance

Check Content Reference

Target Key

5594