From securityonline.info
The OWASP Zed Attack Proxy (ZAP) is easy to use integrated penetration testing tool for finding vulnerabilities in web applications. It is designed to be used by people with a wide range of security experience and as such is ideal for developers and functional testers who are new to penetration testing as well as being a useful addition to an experienced pen testers toolbox.
ZAP provides automated scanners as well as a set of tools that allow you to find security vulnerabilities manually.