Lynis
Lynis is a security auditing tool for Unix-like systems that checks configuration and hardening and suggests improvements.
Legal & ethical use. Use this tool only on systems, networks and data that you own or have explicit written permission to test. Unauthorised access or scanning can break computer-misuse laws (for example Pakistan's Prevention of Electronic Crimes Act, 2016, and equivalents elsewhere). Practise in your own lab or in authorised environments such as CTFs.
What it is used for
- Audit the hardening of your own Linux servers
- Track a hardening index over time
Key features
- Agentless shell-based audit
- Hardening index
- Plugin and compliance tests
Installation
Install from your distribution or clone the GitHub repository.
Beginner usage guide
Run an audit as root on a test machine and work through the "Suggestions" section, re-running to measure improvement.
Example commands
Run these only against your own lab or authorised targets. Placeholder addresses such as 192.0.2.x are documentation ranges.
Audit the local system
sudo lynis audit systemRuns the tests and prints warnings and suggestions; results are logged to /var/log/lynis.log.
Keep learning
🚩 Practice challenge: Permission Audit medium
References
Source verification
Last reviewed: 2026-10-27
Links checked over HTTP: 2026-10-27 07:51 UTC — official: 200, docs: 200, repo: 200
Commands were written from the official documentation and have not been executed on this site; test them in your lab.