ShadowSecurityScanner vs Nessus vs OpenVAS
Choosing a network vulnerability scanner usually comes down to three popular options: the commercial Nessus, the open-source OpenVAS / GVM, and ShadowSecurityScanner — a free, MIT-licensed penetration testing tool that runs as a single desktop app. This page compares them across the criteria that matter most.
| Capability | ShadowSecurityScanner | Nessus | OpenVAS / GVM |
|---|---|---|---|
| License | Open source (MIT) | Proprietary | Open source (GPL) |
| Price | Free | Free tier (16 IPs) / paid Pro | Free |
| Deployment | Single desktop binary | Local service + web UI | Server stack (feeds, scanner, GSA) |
| Setup time | Seconds (download & run) | Minutes | Longer (multi-component) |
| Cloud / telemetry | None — fully offline | Account & activation | Self-hosted |
| EPSS exploit scoring | Built in | Partial | No |
| CISA KEV flagging | Built in | Partial | No |
| Scan diffing | New / regressed / resolved | Limited | Limited |
| SARIF export | Yes | No | No |
| Platforms | Windows · macOS · Linux | Windows · macOS · Linux | Linux |
When to choose ShadowSecurityScanner
Pick ShadowSecurityScanner if you want a zero-setup, privacy-first scanner that you can download and run immediately, with no server to maintain and no data leaving your machine. Its standout feature is exploit-aware prioritisation: findings are ranked by FIRST.org EPSS probability and CISA KEV status, so you fix what attackers actually exploit first. It's a strong fit for individual pentesters, small teams, consultants and anyone who wants a genuinely free, open-source tool.
When to choose Nessus
Nessus is a mature commercial scanner with a very large plugin library and enterprise features (compliance auditing, credentialed scans at scale, support contracts). Its free "Essentials" tier is capped at 16 IP addresses, and the full product is a paid subscription. Choose it when you need vendor support and broad compliance coverage and have the budget.
When to choose OpenVAS / GVM
OpenVAS (part of Greenbone's GVM) is a capable, fully open-source scanner with a large feed of network vulnerability tests. It runs as a multi-component server stack on Linux, which gives flexibility but takes more effort to deploy and maintain. Choose it when you want an always-on, Linux-hosted scanning server and don't mind the setup.
Summary
- Fastest to start & most private: ShadowSecurityScanner — one binary, no cloud.
- Best exploit prioritisation out of the box: ShadowSecurityScanner (EPSS + KEV built in).
- Most enterprise features & support: Nessus (paid).
- Always-on Linux server scanning: OpenVAS / GVM.
Try the free, open-source option
Download ShadowSecurityScanner for Windows, macOS or Linux — a single binary, no installer.
Download ShadowSecurityScannerComparison reflects publicly documented features at the time of writing and is for orientation only; verify current capabilities with each vendor. Nessus is a trademark of Tenable; OpenVAS/GVM are projects of Greenbone. Product names belong to their respective owners.