Ensure noexec option set on /dev/shm partition

MediumLevel 1Automatedcos

Description

The noexec mount option specifies that the filesystem cannot contain executable binaries. Setting this option on a file system prevents users from executing programs from shared memory. This deters users from introducing potentially malicious software on the system.

How it is checked

Audit method: Shell command

shell

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

Expected output: compliant

How it is fixed

Fix method: Guidance or infrastructure patch

Run the following command to remount /dev/shm: # mount -o remount,noexec /dev/shm /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 - 1.1.12 Ensure noexec option set on /dev/shm partition

Check this host

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

shell

tmaegis scan --target cos