OverTheWire’s wargames are offered to help learn and practice security concepts in the form of fun-filled games.
The Leviathan wargame is a little bit more advanced than Bandit but still doesn’t require any knowledge about programming. It is best to first play Bandit and then Leviathan.
It consists of a total of 6 Levels. At each level, you have to find the password for the next level to continue playing. Each Level is a user that you connect as, using SSH in the leviathan.labs.overthewire.org server.