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TMA-ROCKY10-5.1.15

Ensure sshd MACs are configured

MediumLevel 1Automatedlinux

Description

This variable limits the types of MAC algorithms that SSH can use during communication. Notes: • Some organizations may have stricter requirements for approved MACs. • Ensure that MACs used are in compliance with site policy. • The only "strong" MACs currently FIPS 140 3 approved are: o hmac-sha2-256-etm@openssh.com o hmac-sha2-512-etm@openssh.com o hmac-sha2-256 o hmac-sha2-512

How it is checked

Audit method: Shell command

shell
alt0() { o=$(bash -c 'sshd -T | grep -Pi -- '"'"'macs\h+([^#\n\r]+,)?(hmac-md5|hmac-md5-96|hmac-sha1- 96|umac-64@openssh.com|hmac-md5-etm@openssh.com|hmac-md5-96- etm@openssh\.com|hmac-sha1-etm@openssh\.com|hmac-sha1-96- etm@openssh\.com|umac-64-etm@openssh\.com|umac-128-etm@openssh\.com)\b'"'"'' 2>/dev/null); [ -z "$o" ] || { echo "step1: $o" | head -c 300; return 1; }; }; if alt0; then echo compliant; fi
Expected output
compliant

How it is fixed

Fix method: Guidance or infrastructure patch

Note: • First occurrence of an option takes precedence. • Though MACs may be configured through the MACs option in the /etc/ssh/sshd_config file, it is recommended that the MACs available to openSSH server are configured through system-wide-crypto-policy • If the recommendations in the subsection "Configure system wide crypto policy" have been followed, this Audit should be in a passing state. Please review that section before following this Remediation Procedure • By default, system-wide-crypto-policy is applied to the openSSH server. If the following defaults don't exist due to modifications or upgrade from a earlier release, the system-wide-crypto-policy may not be included by the openSSH…

Properties

Operating systems
rocky-10
Tags
cis-convertedlinux
Reference
CIS Rocky Linux 10 Benchmark v1.0.0 - 5.1.15

Check this host

Run this on a machine you are allowed to audit. The scan is read-only.

shell
tmaegis scan --target linux