OpenVAS (OpenSource Vulnerability Assesment Scanner) is a GPL fork of the Nessus security scanner currently controlled by Tenable Network Security.

OpenVAS provides a totally open licensed, freely distributable scanning engine as well as a complete library of plugins and tests which will scan for particular vulnerabilities. Starting from Nessus version 2.2.5 which was released under a GPL license OpenVAS will continue to develop and refine the underlying engine as well as expand the plugin script library and functionality.