Re: Brute-forcing cached Windows login password hashes



So, like I said, mathematically infeasible. Can we have a show of hands
for all those who've got a rainbow table set for the administrator
account? (Government agencies and those with silent black helicopters
need not apply)

Mathieu CHATEAU wrote:
this works if you have the mscache rainbow table that match the login
you want to break...

Cordialement,
Mathieu CHATEAU
http://lordoftheping.blogspot.com


----- Original Message ----- From: "Carl Livitt" <carllivitt@xxxxxxxxx>
To: "Ben Greenberg" <Ben.Greenberg@xxxxxxxxxxxxx>;
<pen-test@xxxxxxxxxxxxxxxxx>
Sent: Thursday, July 26, 2007 4:39 PM
Subject: Re: Brute-forcing cached Windows login password hashes



The hash algorithm is a salted MD4. It's impossible (ok, to be pedantic
it's mathematically infeasible) to use rainbow tables because of the
salting, so that leaves you with dictionary and brute-force.

The latest version of John and the MS Cache Hash patches are all
available from http://openwall.com/john/. I believe v1.7.2 is the latest
version.

Regards,
Carl


Ben Greenberg wrote:
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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