JTR is the penultimate when it comes to password cracking in windows, but for Linux and open source,its the best you can get your hands on.Fire it up with a word list and you are good to go.
Here is a sample output of JTR in Debian environment
root@0[john-1.6.37]# cat wpass.txt
root@0[john-1.6.37]# john -w:password.lst wpass.txt
Loaded 1 password hash (Traditional DES [24/32 4K])
guesses: 1 time: 0:00:00:00 100% c/s: 752 trying: 12345 - pookie