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 server must be configured to use only FIPS-validated key exchange algorithms.

DISA Rule

SV-260533r1208690_rule

Vulnerability Number

V-260533

Group Title

SRG-OS-000033-GPOS-00014

Rule Version

UBTU-22-255060

Severity

CAT II

CCI(s)

• CCI-000068 - Implement cryptographic mechanisms to protect the confidentiality of remote access sessions.

Weight

10

Fix Recommendation

Configure the SSH server to use only FIPS-validated key exchange algorithms.

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

KexAlgorithms ecdh-sha2-nistp256,ecdh-sha2-nistp384,ecdh-sha2-nistp521,diffie-hellman-group-exchange-sha256

Restart SSH for the changes to take effect:

$ sudo systemctl restart ssh

Check Contents

Verify that the SSH server is configured to use only FIPS-validated key exchange algorithms 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 'kexalgorithms'
/etc/ssh/sshd_config:KexAlgorithms ecdh-sha2-nistp256,ecdh-sha2-nistp384,ecdh-sha2-nistp521,diffie-hellman-group-exchange-sha256

If "KexAlgorithms" does not contain only the algorithms "ecdh-sha2-nistp256,ecdh-sha2-nistp384,ecdh-sha2-nistp521,diffie-hellman-group-exchange-sha256" in exact order, is commented out, is missing, or conflicting results are returned, this is a finding.

Vulnerability Number

V-260533

Documentable

False

Rule Version

UBTU-22-255060

Severity Override Guidance

Verify that the SSH server is configured to use only FIPS-validated key exchange algorithms 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 'kexalgorithms'
/etc/ssh/sshd_config:KexAlgorithms ecdh-sha2-nistp256,ecdh-sha2-nistp384,ecdh-sha2-nistp521,diffie-hellman-group-exchange-sha256

If "KexAlgorithms" does not contain only the algorithms "ecdh-sha2-nistp256,ecdh-sha2-nistp384,ecdh-sha2-nistp521,diffie-hellman-group-exchange-sha256" in exact order, is commented out, is missing, or conflicting results are returned, this is a finding.

Check Content Reference

M

Target Key

5594