Kali Linux OS
Kali Linux is built on a Debian based Operating system
Kali Linux is an open source project that is maintained and funded by Offensive Security, a provider of world-class information security training and penetration testing services. In addition to Kali Linux, Offensive Security also maintains the Exploit Database and the free online course, Metasploit Unleashed.
is an advanced Penetration Testing and Security Auditing Linux distribution.