RE: Display User Password?

> So a prerequisite is that you need to be able to know when the correct
> answer is discovered.  To do that offline (e.g., with the program Phil
> and I are talking about), you need the encrypted version of the
> password and the program needs to know the correct encryption method
> to use so it can compute a potential ciphertext and compare to the
> desired ciphertext.

This is an interesting topic.  I know the horse has been beaten before, but
I've never understood the bruteforce method.  How does the password cracker
program *know* when it has found the "clear text" password?  How does it
know that "WHNPIGSFLY" is correct and "$YEAHRIGHT" or "eW_O7q&-8" or any
other result is not?  Does not each permutation generate a result, even if
it's full of hex bytes we'd never be able to type?

db

> -----Original Message-----
> From: midrange-l-bounces@xxxxxxxxxxxx / Douglas Handy
> Sent: Wednesday, September 29, 2004 12:46 AM
>
> Jim,
>
> >is there such a thing as a pwd that cannot be brute forced?
>
> Well, there needs to be some mechanism for testing each brute force
> attempt.  Even with OS/400's silly default restrictions on passwords
> characters and some technical reasons why 8-10 character passwords are
> basically the same strength as 7 character passwords, you still have a
> potential namespace of 126,030,769,230
> possibilities.
>
> Obviously, you wouldn't want to try typing those into a sign-on
> display, regardless of how many attempts you were allowed before it
> disabled the user or ws profile.
>
> So a prerequisite is that you need to be able to know when the correct
> answer is discovered.  To do that offline (e.g., with the program Phil
> and I are talking about), you need the encrypted version of the
> password and the program needs to know the correct encryption method
> to use so it can compute a potential ciphertext and compare to the
> desired ciphertext.
>
> On my PC, it can test over 19 million of those per *second*.
>
> The same program would not work for systems using the 128-char
> password support, for at least two reasons:
>
>  1) the encryption method is different, so you need a different cracker
>  2) the possible permutations is many magnitudes of order higher
>
> Thus even if you had an equivalent cracker program and knew the
> encrypted form of the password, it may take a prohibitively long time
> to discover the correct plaintext form.
>
> Social engineering would probably be a faster way of obtaining
> the password.
>
> Doug