Brute-forcing cached Windows login password hashes

["Ben Greenberg" <Ben.Greenberg () senet-int com>]

Greetings all,
 
My question is regarding the encrypted password hashes that Windows stores in
the registry of the last 10 logins to a workstation.

I read the original white paper written by Arnaud Pilon and I've used his
cachedump tool to extract the password hashes from the registry. What I'm
wondering is what type of hash those passwords use. Is it straight MD4? I
know that each hash is salted with a machine-specific unique string. What I
am unclear on is what exactly the password hash is and how it can be
brute-forced. I know that there is a patch for John the Ripper, but every
mention I can find refers to a two year old version of John. Does anyone know
if the most recent version has this patch in it already? Also, is anyone
familiar with any rainbow tables for cracking these passwords? Are rainbow
tables possible for these hashes because of the salting?

Thanks all.

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