Title

AIX SSH daemon must be configured to only use Message Authentication Codes (MACs) employing FIPS 140-2 approved cryptographic hash algorithms. (Cat II impact)

Discussion

DoD information systems are required to use FIPS 140-2 approved cryptographic hash functions.

Check Content

Check the SSH daemon configuration for allowed MACs by running the following command: # grep -i macs /etc/ssh/sshd_config | grep -v '^#' MACs hmac-sha1,hmac-sha1-96,hmac-sha2-256,hmac-sha2-256-96,hmac-sha2-512,hmac-sha2-512-96 If no lines are returned, or the returned MAC list contains any MAC that is not FIPS 140-2 approved, this is a finding.

Fix Text

Edit the "/etc/ssh/sshd_config" file and add/edit the following line to contain FIPS 140-2 approved ciphers: MACs hmac-sha1,hmac-sha1-96,hmac-sha2-256,hmac-sha2-256-96,hmac-sha2-512,hmac-sha2-512-96 Restart SSH daemon: # stopsrc -s sshd # startsrc -s sshd Note: If the "MACs" configuration contains any ciphers that are not FIPS 140-2 approved, they should be removed from the configuration file.

Additional Identifiers

Rule ID: SV-215294r508663_rule

Vulnerability ID: V-215294

Group Title: SRG-OS-000480-GPOS-00227

Expert Comments

CCIs tied to check.

Controls tied to check. These are derived from the CCIs shown above.