SecGen is a tool designed by Z. Cliffe Schreuders that generates intentionally vulnerable virtual machines that act as black boxes for training purposes. It is very easy to set up and you can have a running target in 10 minutes. SecGen comes with over 100 preconfigured scenarios and supports CTF events. You are also able to design customized scenarios specific to training needs.
After installing its requirements including vagrant and Oracle VirtualBox, you can have a randomly selected online vulnerable black box just by running ruby secgen.rb run. If the virtual machine can’t be reached it may require configuring a host only adapter in VirtalBox. specific scenarios can be selected with ruby secgen.rb -s [xml file] run.
SecGen can be found at https://github.com/cliffe/SecGen