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Fast comparison of Nessus and OpenVAS knowledge bases

In my opinion, quality of knowledge base is the most important characteristic of Vulnerability Management (VM) product. Maybe it’s because I have spent significant amount of time making different security content for vulnerability scanners and this is some form of professional deformation. ๐Ÿ™‚ The fact is that nowadays we have dozens of VM solutions on the market, which have very different knowledge bases and thus different abilities for detecting vulnerabilities. And really nobody talk about this. I can recommend related post “Tenable doesnโ€™t want to be Tenable anymore” and especially HD Moore’s comment to that post. It describes the reason why nobody interested now in quality of detection. Maximum what we, end-users, can hear from the vendor about it’s knowledge base is an amount of vulnerability checks: 40000-80000 and approximate list of supported systems. There is a massive false belief that detection quality of the products is approximately the same and it’s better talk about dashboards, reports, SIEM-like capabilities. To demonstrate that the difference actually exists I made a pretty primitive comparison of Nessus and OpenVAS knowledge bases.

I chose these two products, mainly because information on their NASL plugins is available at As I also wrote earlier how you can use easily parse Vulners archives in python, so you can repeat it for yourself. I talked about this topic at Pentestit webinar about Vulners. If you are familiar with Russian, you can also check this out. ๐Ÿ˜‰ The slides for this presentation are available here.

Why I call this comparison fast and primitive? I don’t define the structure of KBs for this product and don’t carefully map one nasl script to another. I suppose it may be a theme for another posts. Instead I am looking at the CVE links. If two scanners detect can the same vulnerabilities, they should have the same CVE links in all the NASL scripts, right? In reality we have a great difference between the products and more than a half of the CVEs can’t be detected by using both of them.

CVE links from NASL plugins

All CVEs: 80196
OpenVAS CVE links: 29240
Nessus CVE links: 35032
OpenVAS vs. Nessus: 3787;25453;9579

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