The idea behind DVL is to offer an operating system for learning and research for security students. As the DVL website explains:
Damn Vulnerable Linux (DVL) is everything a good Linux distribution isn’t. Its developers have spent hours stuffing it with broken, ill-configured, outdated, and exploitable software that makes it vulnerable to attacks. DVL isn’t built to run on your desktop – it’s a learning tool for security students.
DVL is made by people with significant black hat backgrounds, incorporating the community of www.Reverse-Engineering.net and Crackmes.de. It contains a huge amount of lessons, including lesson descriptions and solutions if the level has been solved by a community member at Crackmes.de.