Helpminecraft 1.5.2 cracked server hacking

Hey Guys!
Can anyone tell me if is possilbe to crack passwords from a cracked server?
it has the plugin to /register ''password'' ''password'' /login ''password''
do its possible to bypass the password or hack it?
Any programs to do it?
Thanks you guys and i am waiting for your opinios and help

Im pretty sure Wolfram or Wurst has a ForceOP for the /register and /login plugins, I think it just guesses it but I haven't needed to use one yet

Yea I think the only way is to brute force the password like fanterstic said.