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

From MAC OSX 10.6 Workstation Security Technical Implementation Guide

Associated with IA controls: DCNR-1

Associated with: CCI-001453

SV-39369r2_rule The SSH daemon must be configured to only use Message Authentication Codes (MACs) employing FIPS 140-2 approved cryptographic hash algorithms.

Vulnerability discussion

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

Check content

Open a terminal session and enter the following command. grep -i macs /etc/sshd_config | grep -v '^#' If no lines are returned, or the returned MACs list contains any MAC other than "hmac-sha1", this is a finding.

Fix text

Open a terminal session and edit the SSH daemon configuration file "/etc/sshd_config" and remove any MACs other than "hmac-sha1". If there is no MACs line in "/etc/sshd_config", add "MACs hmac-sha1" to the file. Restart the SSH daemon for the changes to take effect.

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