w3af - w3af is a Web Application Attack and Audit Framework
Shodan - Shodan is the world's first search engine for Internet-connected devices.
Nikto - Nikto is an Open Source (GPL) web server scanner which performs comprehensive tests against web...
Censys - Censys helps organizations, individuals, and researchers find and monitor every server on the Internet to reduce exposure and improve security.
Nessus - Nessus Professional is a security platform designed for businesses who want to protect the security of themselves, their clients, and their customers.
Exploit Pack - Exploit Pack is an open source project security that will help you adapt exploit codes on-the-fly.