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 configure the SSH client to use FIPS 140-3 approved ciphers to prevent the unauthorized disclosure of information and/or detect changes to information during transmission.

DISA Rule

SV-270670r1067115_rule

Vulnerability Number

V-270670

Group Title

SRG-OS-000250-GPOS-00093

Rule Version

UBTU-24-100850

Severity

CAT II

CCI(s)

CCI-001453 - Implement cryptographic mechanisms to protect the integrity of remote access sessions.

Weight

Fix Recommendation

Configure the Ubuntu 24.04 LTS SSH client to use only ciphers employing FIPS 140-3 approved algorithms by updating the "/etc/ssh/ssh_config" file with the following line:

Ciphers aes256-gcm@openssh.com,aes128-gcm@openssh.com,aes256-ctr,aes128-ctr

Restart the "ssh" service for changes to take effect:

$ sudo systemctl restart ssh

Check Contents

Verify the SSH client is configured to use only ciphers employing FIPS 140-3 approved algorithms with the following command:

$ sudo grep -r 'Ciphers' /etc/ssh/ssh_config*
Ciphers aes256-gcm@openssh.com,aes128-gcm@openssh.com,aes256-ctr,aes128-ctr

If any ciphers other than "Ciphers aes256-gcm@openssh.com,aes128-gcm@openssh.com,aes256-ctr,aes128-ctr" are listed, the "Ciphers" keyword is missing, or the returned line is commented out, or if multiple conflicting ciphers are returned, this is a finding.

Vulnerability Number

V-270670

Documentable

False

Rule Version

UBTU-24-100850

Severity Override Guidance

Check Content Reference

Target Key

5673