The Open Vulnerability Assessment System (OpenVAS) is a framework of several services and tools offering a comprehensive and powerful vulnerability scanning and vulnerability management solution.
The actual security scanner is accompanied with a daily updated feed of Network Vulnerability Tests (NVTs), over 20,000 in total (as of January 2011).
All OpenVAS products are Free Software. Most components are licensed under the GNU General Public License (GNU GPL).
Learn more about the OpenVAS components and features on the OpenVAS-Software page