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Date: Mon, 29 May 2006 16:16:37 -0500
From: "Randy B" <>
Subject: Re: How does it actually dictionary attack salted hashes?

Dictionary attacks are simply "intelligent" brute-forces; they reduce
the problem set to a more probable range of solutions, and attempt to
solve.  In writing John, Solar Designer took it a step further and has
performed analysis of how often certain words or characters/character
clusters appear in common passwords.  Without the very intelligent
(and highly manual) wordlists, character frequency tables, mangling
rules, and the order they run in, John would simply be a very fast
brute-force engine.


On 5/29/06, John Paine <> wrote:
> If Unix password hashes normally contain a 12 bit salt, how can JTR, or any
> other cracking program who excepts /etc/shadow lines, be effective at
> allowing a user to supply a dictionary list? Lets say for example the salt
> was 'foobar' and the password was 'password'.  How do these cracking program
> allow a dictionary list to be run on a hash such as  foobarpasswordfoobar? I
> can see how brute forcing would work, as well as taking more work overall to
> do, but I don't understand how John the Ripper can also crack it by
> dictionary. I ask because I don't know.
> Thanks.

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