# Cis Ubuntu1204 V110 2 15

> Add nosuid Option to /run/shm Partition

- Skill: `cyberstrikeus/cis-ubuntu1204-v110-2-15` (Agent Skill)
- Install (CLI): `npx skillmds@latest add cyberstrikeus/cis-ubuntu1204-v110-2-15`
- Raw SKILL.md: https://api.skillmd.com/api/skills/cyberstrikeus/cis-ubuntu1204-v110-2-15/raw
- Safety review: PASS (external: skill-scanner PASS, skillspector PASS)
- Works with: Claude Code, Claude.ai, OpenAI Codex
- Category: Coding & Dev Tools
- Author: cyberstrikeus (https://skillmd.com/u/cyberstrikeus)
- Updated: 2026-09-17
- Page: https://skillmd.com/skills/cyberstrikeus/cis-ubuntu1204-v110-2-15

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# 2.15 Add nosuid Option to /run/shm Partition (Scored)

## Profile Applicability

- Level 1

## Description

The `nosuid` mount option specifies that the `/run/shm` (temporary filesystem stored in memory) will not execute `setuid` and `setgid` on executable programs as such, but rather execute them with the uid and gid of the user executing the program.

## Rationale

Setting this option on a file system prevents users from introducing privileged programs onto the system and allowing non-root users to execute them.

## Audit Procedure

### Using Command Line

```bash
grep /run/shm /etc/fstab | grep nosuid
mount | grep /run/shm | grep nosuid
```

## Expected Result

Both commands should return output showing `nosuid` is set. If either command emits no output then the system is not configured as recommended.

## Remediation

### Using Command Line

Edit the `/etc/fstab` file and add `nosuid` to the fourth field (mounting options). Look for entries that have mount points that contain `/run/shm`. See the `fstab(5)` manual page for more information.

```bash
mount -o remount,nosuid /run/shm
```

## Default Value

By default, the `nosuid` option is not set on the `/run/shm` partition.

## References

- CIS Ubuntu 12.04 LTS Server Benchmark v1.1.0

## Profile

Level 1 - Scored