OL6-00-000243 - The Oracle Linux 6 operating system must implement DoD-approved encryption to protect the confidentiality of SSH connections.

Information

Approved algorithms should impart some level of confidence in their implementation. These are also required for compliance.
The system will attempt to use the first cipher 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 cipher available to secure the SSH connection.

Solution

Limit the ciphers to those algorithms which are FIPS-approved. The following line in '/etc/ssh/sshd_config' demonstrates use of FIPS-approved ciphers:

Ciphers 256-ctr,aes192-ctr,aes128-ctr

Note: The man page 'sshd_config(5)' contains a list of supported ciphers.

See Also

https://dl.dod.cyber.mil/wp-content/uploads/stigs/zip/U_Oracle_Linux_6_V2R7_STIG.zip

Item Details

Category: ACCESS CONTROL

References: 800-53|AC-17(2), CAT|II, CCI|CCI-001453, Rule-ID|SV-219561r793818_rule, STIG-ID|OL6-00-000243, STIG-Legacy|SV-65013, STIG-Legacy|V-50807, Vuln-ID|V-219561

Plugin: Unix

Control ID: dd77d4dc3e15cbf0b98fa6c5b6ec3a404a343bf5c42dc5cc6868e22e6f8c6734