Vulnerability 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 employed algorithms can be viewed in the /etc/crypto-policies/back-ends/openssl.config file.

Check

Verify that RHEL 9 OpenSSL library is configured to use TLS 1.2 encryption or stronger with following command:

$ grep -i minprotocol /etc/crypto-policies/back-ends/opensslcnf.config

TLS.MinProtocol = TLSv1.2
DTLS.MinProtocol = DTLSv1.2

If the "TLS.MinProtocol" is set to anything older than "TLSv1.2" or the "DTLS.MinProtocol" is set to anything older than "DTLSv1.2", this is a finding.

Fix

Configure the RHEL 9 OpenSSL library to use only DOD-approved TLS encryption by editing the following line in the "/etc/crypto-policies/back-ends/opensslcnf.config" file:

TLS.MinProtocol = TLSv1.2
DTLS.MinProtocol = DTLSv1.2

A reboot is required for the changes to take effect.