Damn Vulnerable Linux

It functions as a tool for observing and studying vulnerabilities in the Linux kernel and popular user space software.

It is available as a live CD, and can be run through a virtual machine within the host operating system.

[2] DVL was created by Thorsten Schneider, the founder of the TeutoHack laboratory at Bielefeld University,[3] to use as a training system for his university lectures.

DVL is a SLAX-based distribution, and uses the Slackware .tgz package management system.

[1] It uses outdated versions of various software, to deliberately make it the most vulnerable operating system ever.