Nikto is one of the best free cyber security tools for conducting web vulnerabilities. It scans web servers for dangerous files or out-dated software and other related problems. It has a database of 6400 different types of threats which are used in the web vulnerability scan. 

The database is constantly updated for it to be able to identify the new vulnerabilities. Also new plugins are developed and released to  ensure the compatibility of the software with different systems.

Download link- https://github.com/sullo/nikto

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some features might not work!!!