Mutillidae is a free and open source web application which can be used by security experts who want to use their penetration testing tools and hack a website. Mutillidae can be installed on any computer with a web server. You can easily install a web server on your personal computer by using XAMPP which installs a web server (Apache), a database (MySQL) and several other tools. Mutillidae has several vulnerabilities and hints which makes hacking very easy. It can be used by security experts who want to test their penetration testing applications, by students who learn about web application security and in general by any security enthusiast who wants to learn the vulnerabilities of a web application and how hackers exploit them to gain access. You can visit SourceForge website to see the full list of Mutillidae’s features and download it.