Nikto is an Open Source (GPL) web server scanner which performs comprehensive tests against web servers for multiple items, including over 6400 potentially dangerous files/CGIs, checks for outdated versions of over 1200 servers, and version specific problems on over 270 servers. It also checks for server configuration items such as the presence of multiple index files, HTTP server options, and will attempt to identify installed web servers and software. Scan items and plugins are frequently updated and can be automatically updated.
For downloads and more information,
visit the Nikto homepage.
Nikto is very good scanner, yes it's old but still can detect flaws that would be missed with other scanners. In combination with w3af, Nessus (openvas) and maybe Acunetix it would be pretty much complete automated discovery of security flaws of servers and web applications. http://tz-security.com
I've had to research this tool for an assignment for my I.T studies... For an open-source tool, I found it to be very impressive - it made me aware of errors on my Debian VPS I wasn't even aware of. I was also suprised of the vast amount of features it offered, and the types of tests that are available to run. I find it a great tool to test clients' websites and make sure the servers are secure.