Damn Vulnerable Linux (DVL)
Damn Vulnerable Linux (DVL) is a Slackware and Slax-based live DVD purposefully stuffed with broken, ill-configured, outdated and exploitable software, began life as a training system used during the author’s university lectures.
Its primary goal is to design a Linux system that is as vulnerable as possible — in order to teach and demonstrate a variety of security topics, including reverse code engineering, buffer overflows, shell code development, web exploitation, and SQL injection.
It contains older, easily breakable versions of Apache, MySQL, PHP, and FTP and SSH daemons, as well as several tools available to help you compile, debug, and break applications running on these services, including GCC, GDB, NASM, strace, ELF Shell, DDD, LDasm, LIDa, and more.
So if you are looking for a new playground, DVL is a good choice for you.