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-215294r508663_rule		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	2022-06-06

Details

Check Text ( C-16492r294333_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.