Protostar introduces the following in a friendly way:
In order to make this as easy as possible to introduce Address Space Layout Randomisation and Non-Executable memory has been disabled.
Once the virtual machine has booted, you are able to log in as the "user" account with the password "user" (without the quotes).
The levels to be exploited can be found in the /opt/protostar/bin directory.
For debugging the final levels, you can log in as root with password "godmode" (without the quotes)
README! The /proc/sys/kernel/core_pattern is set to /tmp/core.%s.%e.%p. This means that instead of the general ./core file you get, it will be in a different directory and different file name.