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 immediately terminate all network connections associated with SSH traffic after a period of inactivity.

DISA Rule

SV-270742r1066715_rule

Vulnerability Number

V-270742

Group Title

SRG-OS-000163-GPOS-00072

Rule Version

UBTU-24-600000

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

10

Fix Recommendation

Configure Ubuntu 24.04 LTS to automatically terminate inactive SSH sessions after a period of inactivity.

Modify or append the following line in the "/etc/ssh/sshd_config" file, replacing "[Count]" with a value of 1:

ClientAliveCountMax 1

Restart the SSH daemon for the changes to take effect:

$ sudo systemctl restart ssh.service

Check Contents

Verify that all network connections associated with SSH traffic automatically terminate after a period of inactivity with the following command:

$ sudo grep -ir ClientAliveCountMax /etc/ssh/sshd_config*
/etc/ssh/sshd_config:ClientAliveCountMax 1

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

Vulnerability Number

V-270742

Documentable

False

Rule Version

UBTU-24-600000

Severity Override Guidance

Verify that all network connections associated with SSH traffic automatically terminate after a period of inactivity with the following command:

$ sudo grep -ir ClientAliveCountMax /etc/ssh/sshd_config*
/etc/ssh/sshd_config:ClientAliveCountMax 1

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

Check Content Reference

M

Target Key

5673