AIX SSH daemon must be configured to only use Message Authentication Codes (MACs) employing FIPS 140-2 approved cryptographic hash algorithms.
Overview
| Finding ID | Version | Rule ID | IA Controls | Severity |
| V-215294 | AIX7-00-002111 | SV-215294r991589_rule | CCI-000366 | medium |
| Description | ||||
| DoD information systems are required to use FIPS 140-2 approved cryptographic hash functions. | ||||
| STIG | Date | |||
| IBM AIX 7.x Security Technical Implementation Guide | 2024-08-16 | |||
Details
Check Text (C-215294r991589_chk)
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 (F-16490r294334_fix)
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.