TMA-COS-5.1.9
Ensure SSH HostbasedAuthentication is disabled
MediumLevel 1Automatedcos
Description
The HostbasedAuthentication parameter specifies if authentication is allowed through trusted hosts via the user of .rhosts, or /etc/hosts.equiv, along with successful public key client host authentication. This option only applies to SSH Protocol Version 2. Even though the .rhosts files are ineffective if support is disabled in /etc/pam.conf, disabling the ability to use .rhosts files in SSH provides an additional layer of protection.
How it is checked
Audit method: Shell command
shell
alt0() { command -v grep >/dev/null 2>&1 || { echo "step1: grep not installed"; return 1; }; command -v sshd >/dev/null 2>&1 || { echo "step1: sshd not installed"; return 1; }; o=$(bash -c 'sshd -T | grep hostbasedauthentication' 2>&1); printf '%s\n' "$o" | tr -s ' \t' ' ' | sed 's/^ //;s/ $//' | grep -Fxq -- 'HostbasedAuthentication no' || { echo step1: missing 'HostbasedAuthentication no'; 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: HostbasedAuthentication no
Properties
- Operating systems
- Any
- Tags
- authcontainer-optimized-oscosssh
- Reference
- CIS Google Container-Optimized OS Benchmark v1.2.0 - 5.1.9 Ensure SSH HostbasedAuthentication is disabled
Check this host
Run this on a machine you are allowed to audit. The scan is read-only.
shell
tmaegis scan --target cos