ALMA-09-002990 - AlmaLinux OS 9 SSH client must be configured to use only encryption ciphers employing FIPS 140-3-validated cryptographic hash algorithms to protect the confidentiality of SSH client connections.

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.

AlmaLinux OS 9 incorporates systemwide crypto policies by default. Configuration files in /etc/ssh/ have no effect on the ciphers, MACs, or algorithms used by the operating system. The employed ssh client algorithms can be viewed in the /etc/crypto-policies/back-ends/openssh.config file.

Solution

Configure the AlmaLinux OS 9 SSH client to use only ciphers employing FIPS 140-3-approved algorithms.

Reinstall crypto-policies with the following command:

$ sudo dnf -y reinstall crypto-policies

Set the crypto-policy to FIPS with the following command:

$ sudo update-crypto-policies --set FIPS

Setting system policy to FIPS

See Also

https://dl.dod.cyber.mil/wp-content/uploads/stigs/zip/U_CL_AlmaLinux_OS_9_V1R3_STIG.zip

Item Details

Category: ACCESS CONTROL

References: 800-53|AC-17(2), CAT|II, CCI|CCI-001453, Rule-ID|SV-269113r1107624_rule, STIG-ID|ALMA-09-002990, Vuln-ID|V-269113

Plugin: Unix

Control ID: 2784ecb665bd130af80dbc3689fac04987b4a5156d24cdfaec5eabdee28499f0