---
title: "HOST-FS-013 Temporary Filesystems Allow Executables"
canonical: https://openvapt.com/checks/HOST-FS-013.html
html: https://openvapt.com/checks/HOST-FS-013.html
site: OpenVAPT, https://openvapt.com/
license: OpenVAPT Source-Available Licence 1.3, https://openvapt.com/legal/licence-text.html
modified: 2026-10-14
version: 0.1.0-alpha.6
---

# HOST-FS-013 Temporary Filesystems Allow Executables

Checks that /tmp, /var/tmp and /dev/shm, where they are separate mounts, carry the noexec option.

- Domain: Server
- Severity: Low
- Control category: Secure Configuration
- Fix effort: medium
- CVSS v3.1 vector: `CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:N/I:L/A:N`
- CIS Controls v8: 4.1
- NIST CSF 2.0: PR.PS-01
- CWE: CWE-276
- NIST SP 800-53 Rev. 5: CM-6, CM-7
- Benchmark topic: noexec on temporary filesystems (CIS Controls v8 4.1) (topic only, no benchmark text)

## Why It Matters

Attackers who gain a foothold download tools into a world-writable temporary directory and run them from there. noexec makes that step fail and forces noisier workarounds.

## How It Detects

Reads /proc/mounts. Each of /tmp, /var/tmp and /dev/shm that appears as a mount must include noexec; paths that are not separate mounts are skipped (HOST-FS-008 covers nodev and nosuid, HOST-FS-010 covers /var/tmp as a mount).

## How to Fix

Add noexec to the mount options of each temporary filesystem (systemd tmp.mount drop-in or /etc/fstab) and remount. Some package managers need exec on /tmp during installs; set TMPDIR for them rather than removing noexec.

## How to Verify

```
findmnt -no TARGET,OPTIONS /tmp /var/tmp /dev/shm
```

## Learn the Theory

- [P1 Linux Server Hardening](https://openvapt.com/academy/p1.md)
- [P17 Kernel, Filesystem and Boot Hardening](https://openvapt.com/academy/p17.md)

## References

- [mount(8), Linux man-pages (nodev, nosuid, noexec)](https://man7.org/linux/man-pages/man8/mount.8.html)
- [NIST SP 800-123, Guide to General Server Security](https://csrc.nist.gov/pubs/sp/800/123/final)

## Source Code

https://github.com/OpenVAPT/openvapt/blob/574f7f3333c44b75a3c649e2d93a76d507f75adf/internal/checks/host/files_mounts.go

Run it: `openvapt scan --only HOST-FS-013`. Read it offline: `openvapt explain HOST-FS-013`.

---

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