TMA-COS-5.1.4

Ensure SSH Protocol is set to 2

MediumLevel 1Automatedcos

Description

Older versions of SSH support two different and incompatible protocols: SSH1 and SSH2. SSH1 was the original protocol and was subject to security issues. SSH2 is more advanced and secure. SSH v1 suffers from insecurities that do not affect SSH v2.

How it is checked

Audit method: Shell command

shell

alt0() { command -v grep >/dev/null 2>&1 || { echo "step1: grep not installed"; return 1; }; o=$(bash -c 'grep ^Protocol /etc/ssh/sshd_config' 2>&1); printf '%s\n' "$o" | tr -s ' \t' '  ' | sed 's/^ //;s/ $//' | grep -Fxq -- 'Protocol 2' || { echo step1: missing 'Protocol 2'; return 1; }; }; if alt0; then echo compliant; fi

Expected output: compliant

How it is fixed

Fix method: Guidance or infrastructure patch

Edit the /etc/ssh/sshd_config file to set the parameter as follows: Protocol 2

Properties

Operating systems: Any
Tags: container-optimized-oscosssh
Reference: CIS Google Container-Optimized OS Benchmark v1.2.0 - 5.1.4 Ensure SSH Protocol is set to 2

Check this host

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

shell

tmaegis scan --target cos