Check: SLES-12-030180
SLES 12 STIG:
SLES-12-030180
(in versions v2 r13 through v2 r2)
Title
The SUSE operating system SSH daemon must be configured to only use Message Authentication Codes (MACs) employing FIPS 140-2 approved cryptographic hash algorithms. (Cat II impact)
Discussion
Without cryptographic integrity protections, information can be altered by unauthorized users without detection. Remote access (e.g., RDP) is access to DoD nonpublic information systems by an authorized user (or an information system) communicating through an external, nonorganization-controlled network. Remote access methods include, for example, dial-up, broadband, and wireless. Cryptographic mechanisms used for protecting the integrity of information include, for example, signed hash functions using asymmetric cryptography enabling distribution of the public key to verify the hash information while maintaining the confidentiality of the secret key used to generate the hash. The system will attempt to use the first hash presented by the client that matches the server list. Listing the values "strongest to weakest" is a method to ensure the use of the strongest hash available to secure the SSH connection. Satisfies: SRG-OS-000125-GPOS-00065, SRG-OS-000394-GPOS-00174
Check Content
Verify the SUSE operating system SSH daemon is configured to only use MACs that employ FIPS 140-2 approved hashes. Check that the SSH daemon is configured to only use MACs that employ FIPS 140-2 approved hashes with the following command: # sudo grep -i macs /etc/ssh/sshd_config MACs hmac-sha2-512,hmac-sha2-256 If any hashes other than "hmac-sha2-512" or "hmac-sha2-256" are listed, the order differs from the example above, they are missing, or the returned line is commented out, this is a finding.
Fix Text
Configure the SUSE operating system SSH daemon to only use MACs that employ FIPS 140-2 approved hashes. Edit the "/etc/ssh/sshd_config" file to uncomment or add the line for the "MACs" keyword and set its value to "hmac-sha2-512" and/or "hmac-sha2-256" (The file might be named differently or be in a different location): MACs hmac-sha2-512,hmac-sha2-256
Additional Identifiers
Rule ID: SV-217271r877395_rule
Vulnerability ID: V-217271
Group Title: SRG-OS-000125-GPOS-00065
Expert Comments
CCIs
| Number | Definition |
|---|---|
| CCI-000877 |
The organization employs strong authenticators in the establishment of nonlocal maintenance and diagnostic sessions. |
| CCI-001453 |
The information system implements cryptographic mechanisms to protect the integrity of remote access sessions. |
| CCI-003123 |
The information system implements cryptographic mechanisms to protect the confidentiality of nonlocal maintenance and diagnostic communications. |