PHTN-40-000239 The Photon operating system must implement only approved Message Authentication Codes (MACs) to protect the integrity of remote access sessions.

Information

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.

Solution

Navigate to and open:

/etc/ssh/sshd_config

Ensure the "MACs" line is uncommented and set to the following:

MACs hmac-sha2-512,hmac-sha2-256

At the command line, run the following command:

# systemctl restart sshd.service

See Also

https://dl.dod.cyber.mil/wp-content/uploads/stigs/zip/U_VMW_vSphere_8-0_Y24M08_STIG.zip

Item Details

Category: ACCESS CONTROL

References: 800-53|AC-17(2), CAT|I, CCI|CCI-001453, Rule-ID|SV-258900r991554_rule, STIG-ID|PHTN-40-000239, Vuln-ID|V-258900

Plugin: Unix

Control ID: 5d5ef70d634bd7de92103cb54fd658f9c5a9f217697790a1eabe3f0993c77a9f