Prior versions of Nessus were released under the GPL open-source license, but version 3 has become closed-source free software amid some controversy from open-source and GPL advocates. The release offers an entirely new scanning engine with significant performance improvements that make it at least twice as fast, on average, compared to Nessus 2. Versions of Nessus 3 for Windows 2000/XP/2003, Mac OS X and Solaris will not be released until early 2006. Other platforms, such as OpenBSD, are not supported.
Tenable Security, the sole sponsor of Nessus, has moved Nessus to the closed-source realm to improve adoption of its commercial products which significantly enhance Nessus for enterprise environments. The company was founded by Nessus author Renaud Deraison, Dragon IDS author Ron Gula, and Jack Huffard, along with Markus Ranum as the CSO.
Nessus remains the world's most popular free vulnerability scanner, and is used by hackers, security professionals, and organizations alike to test systems and networks for security vulnerabilities. Infocus articles discussing Nessus' use are available. Tenable continues to maintain the Nessus 2.x GPL branch and also still offers 7-day delayed access to more than 9,000 vulnerability checks via its free, registered feed.
Posted by: Kelly Martin