Kali Linux is a Debian-based Linux distribution aimed at advanced Penetration Testing and Security Auditing. Kali contains several hundred tools which are geared towards various information security tasks, such as Penetration Testing, Security research, Computer Forensics and Reverse Engineering. Kali Linux is developed, funded and maintained by Offensive Security, a leading information security training company. What is Persistence? For USB Linux users, a persistent Linux install is one that allows its user to save data changes back to the USB storage device instead of leaving the information in system RAM. This data can then be recovered and used again on subsequent boots, even when booting from different machines. Typically a separate Persistent storage space (persistent overlay) is used in conjunction with a compressed Live Linux OS.