Ensure nosuid option set on /var partition

LowLevel 2Automatedcos

Description

The nosuid mount option specifies that the filesystem cannot contain setuid files. Since the /var filesystem is only intended for temporary dynamic data, set this option to ensure that users cannot create setuid files in /var.

How it is checked

Audit method: Shell command

shell

if ! findmnt -kn /var >/dev/null 2>&1; then echo compliant; elif findmnt -kn /var | grep -qw -- nosuid; then echo compliant; else echo /var' is mounted without nosuid'; fi

Expected output: compliant

How it is fixed

Fix method: Guidance or infrastructure patch

Run the following command to remount /var : # mount -o remount,nosuid /var /etc is stateless on Container-Optimized OS. Therefore, /etc cannot be used to make these changes persistent across reboots. The steps mentioned above needs to be performed after every boot.

Properties

Operating systems: Any
Tags: container-optimized-oscos
Reference: CIS Google Container-Optimized OS Benchmark v1.2.0 - 1.1.6 Ensure nosuid option set on /var partition

Check this host

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

shell

tmaegis scan --target cos --level 2