OWASP Mutillidae II is a free, open-source, deliberately vulnerable web application providing a target for web-security training. Easy-to-use web hacking environment for labs, security enthusiasts, classrooms, CTF, and vulnerability assessment tools. Contains dozens of vulnerabilities and hints; covers OWASP Top Ten 2007–2017. Installable on LAMP, WAMP, XAMPP; pre-installed on SamuraiWTF and OWASP BWA.