Nessus
Nessus is a commercial vulnerability scanner from Tenable (a limited free "Essentials" edition is offered; check Tenable for current terms).
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
- Scan servers and network devices for known vulnerabilities and misconfigurations
- Produce compliance and patch-audit reports
Key features
- Large plugin library
- Credentialed and uncredentialed scans
- Policy templates
Installation
Download the installer from tenable.com after registering; see the documentation for setup.
Beginner usage guide
Start with a basic network scan of your lab, then try a credentialed scan to see how much more it finds.
Example commands
Run these only against your own lab or authorised targets. Placeholder addresses such as 192.0.2.x are documentation ranges.
Workflow (UI)
New Scan → Basic Network Scan → enter lab targets → LaunchReview findings sorted by severity.
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.