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Date: Tue, 13 Aug 2013 16:56:22 -0400
From: Rich Rumble <richrumble@...il.com>
To: john-users@...ts.openwall.com
Subject: Re: Help a newbie to crack a password

On Tue, Aug 13, 2013 at 7:19 AM, Victor le Breton <vbis@...reton.com> wrote:

> So i guess 7z have hashes.
>
> But i have no idea how to get them. If you could help me, I will be very
> gratefull.
> Since there is no 7zip on OSX, the program used to create the file and
> password isKeka <http://www.kekaosx.com/>. It is based on p7zip. I don't
> know if it uses the same SHA-256 hash, I couldn't find that info.
>
I am assuming you're using windows.
You need to run the 7z2john.py (python script) script. I tried to make an
exe from the python script but I was unable to do so with python 2.6. I may
have to try more recent versions. Also it appears even if I had, the python
script doesn't support 7z's that don't have the headers encrypted
"7-Zip files without header encryption are *not* supported yet!"
Which means that if the filename aren't encrypted the script won't produce
a hash... I don't remember this caveat previously, so maybe this will put
some more presure to get a more "vanilla" or typical use-case where the
file names are not encrypted implemented.

You'll have to install python, as well as some python modules to get the
script to work. If I get an exe version turned out soon I'll let you know.
(but probably not until that previous requirement is taken care of)

python 7z2john.py 7zip_file_here.7z >output.txt
That will send the hash into a file called output.txt. You can then run
john in various modes to try to crack the password hash. If you have a
multi-processor box it will go faster if you use the "OMP" build of JtR.
http://openwall.info/wiki/john/custom-builds

john-omp.exe output.txt
That will start the single crack, wordlist and then incremental modes. Or
you can use
john-omp.exe -i output.txt
to jump right into incremental mode. The more you can remember about the
password the better in most cases, you should try to make a small list of
possible passwords, then try that list against the file.
john-omp.exe output.txt -w=guesses.txt   where guesses.txt is the file you
put your guesses in. You should probably try the various rules inside the
john.conf file, rules like
john-omp.exe output.txt -w=guesses.txt -rules=single
or -rules=wordlist, or -rules=NT
-rich

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