Nikto is an Open Source (GPL) web server scanner which performs comprehensive tests against web servers for multiple items, including over 6700 potentially dangerous files/programs, checks for outdated versions of over 1250 servers, and version specific problems on over 270 servers. Developed by Chris Sullo and David Lodge
License: Open Source
Nikto is an open-source web application scanner that is flexible and free to use, making it suitable for quick vulnerability assessments, though it requires technical expertise. Acunetix, on the other hand, is a commercial tool with a user-friendly interface, comprehensive scanning capabilities, and excellent support, making it ideal for organizations looking for a robust security solution.