STIGQter: STIG Summary: Red Hat Enterprise Linux 9 Security Technical Implementation Guide Version: 2 Release: 9 Benchmark Date: 01 Jul 2026:

The RHEL 9 SSH client must be configured to use only DOD-approved Message Authentication Codes (MACs) employing FIPS 140-3 validated cryptographic hash algorithms to protect the confidentiality of SSH client connections.

DISA Rule

SV-270178r1184310_rule

Vulnerability Number

V-270178

Group Title

SRG-OS-000250-GPOS-00093

Rule Version

RHEL-09-255070

Severity

CAT I

CCI(s)

CCI-001453 - Implement cryptographic mechanisms to protect the integrity of remote access sessions.

Weight

Fix Recommendation

Configure the SSH client to use only MACs 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

Note: Systemwide crypto policies are applied on application startup. It is recommended to restart the system for the change of policies to fully take place.

Check Contents

Verify the SSH client is configured to use only MACs employing FIPS 140-3 approved algorithms.

To verify the MACs in the systemwide SSH configuration file, use the following command:

$ grep -i MACs /etc/crypto-policies/back-ends/openssh.config

MACs hmac-sha2-256-etm@openssh.com,hmac-sha2-512-etm@openssh.com,hmac-sha2-256,hmac-sha2-512

If the MACs entries in the "openssh.config" file have any hashes other than "hmac-sha2-256-etm@openssh.com,hmac-sha2-512-etm@openssh.com,hmac-sha2-256,hmac-sha2-512", or they are missing or commented out, this is a finding.

Vulnerability Number

V-270178

Documentable

False

Rule Version

RHEL-09-255070

Severity Override Guidance

Check Content Reference

Target Key

5551