RHEL 9 must implement DOD-approved encryption in the OpenSSL package.

STIG ID: RHEL-09-672035  |  SRG: SRG-OS-000250-GPOS-00093 | Severity: medium |  CCI: CCI-001453

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 only ciphers employing FIPS 140-3 approved algorithms with the following command:

$ sudo grep -i opensslcnf.config /etc/pki/tls/openssl.cnf

.include = /etc/crypto-policies/back-ends/opensslcnf.config

If the "opensslcnf.config" is not defined in the "/etc/pki/tls/openssl.cnf" file, this is a finding.

Fix

Configure the RHEL 9 OpenSSL library to use the system cryptographic policy.

Edit the "/etc/pki/tls/openssl.cnf" and add or modify the following line:

.include = /etc/crypto-policies/back-ends/opensslcnf.config