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Date: Thu, 17 Sep 2020 09:23:04 +0200
From: magnum <john.magnum@...hmail.com>
To: john-users@...ts.openwall.com
Subject: Re: cracking encrypted zip file
On 2020-09-16 14:53, Jasper Jones wrote:
> Just a brief update on this: I've started it running in Prince mode with a
> reasonable word list, and it looks like I have (up to) about three days to
> wait for an outcome.
Here are some further tuning hints: Prince mode defaults to generate
candidates from length 1 to 16 characters, using 1 to 8 elements of the
wordlist. If you know the correct password is definitely within a
certain other length span, stating it with eg. "--min-len=8
--max-len=12" options can be rewarding.
Also, there's --prince-elem-cnt-min and --prince-elem-cnt-max. Let's say
you know there will be at least 5 elements (components) in the correct
password but no more than 6, --prince-elem-cnt-min=5
--prince-elem-cnt-max=6 will stop PRINCE mode from producing long
candidates from *only* digits and punctuation, for example.
So a candidate list of:
1
2
3
sierra
hotel
...and options "--min-len=8 --max-len=12 --prince-elem-cnt-min=5
--prince-elem-cnt-max=6", will produce candidates such as:
hotel1233 (length 9, 5 elements)
123sierra32 (length 11, 6 elements)
...but not
sierra2hotel (too few elements)
sierra123hotel (too long word)
Carefully picking these options can *greatly* reduce the produced
keyspace - just don't limit it too much, you might miss the correct
combination!
magnum
> I also did some more reading about how AES-256 is implemented. Please
> ignore my comment above about the reference to SHA-1. As I now understand
> it, this relates to how the AES-256 key is generated from the password (and
> salt) before being used to encrypt the data.
>
> Thanks again.
>
> Jasper
>
> On Wed, 16 Sep 2020 at 06:57, Jasper Jones <jazjones9292@...il.com> wrote:
>
>>> I'm going to run a test to see if it finds a known password.
>>
>> Okay, so that works, which means I can now work on getting together the
>> right combination of words to have a stab at the real thing. I have a nasty
>> suspicion that I may be back looking for help with mask mode at some point,
>> but thanks so much for your help magnum, I appreciate it.
>>
>> Jasper
>>
>> On Wed, 16 Sep 2020 at 06:47, Jasper Jones <jazjones9292@...il.com> wrote:
>>
>>> I just tried running it on a short list of the most likely words to see
>>> if anything jumps out. Ran for ~5 mins and just got "session completed" at
>>> the end, which I assume means nothing was found.
>>>
>>> I got the following message when I started it:
>>> "Warning: detected hash type "ZIP", but the string is also recognised as
>>> "ZIP-opencl"
>>> Use the "--form=ZIP-opencl" option to force loading these as that type
>>> instead"
>>>
>>> Any issue with that?
>>>
>>> Then:
>>> "Using default input encoding: UTF8
>>> Loaded 1 password hash (ZIP, WinZip, [PKDF2-SHA1 128/128 AVX 4x1)"
>>>
>>> Does that look right? The reference to PKDF2-SHA1 instead of AES concerns
>>> me, but I appreciate that could just be my ignorance showing.
>>>
>>> I'm going to run a test to see if it finds a known password.
>>>
>>> Thanks again
>>> Jasper
>>>
>>> On Wed, 16 Sep 2020 at 06:26, Jasper Jones <jazjones9292@...il.com>
>>> wrote:
>>>
>>>> Thanks very much magnum. I was pretty stressed while doing this last
>>>> night and missed out the '>'before the file name when using zip2john. I now
>>>> have a txt file with what looks like a hash.
>>>>
>>>> That said, I'm still getting an error as well: "ver 5.1
>>>> wallet.zip/wallet.dat is not encrypted, or stored with non-handled
>>>> compression type".
>>>>
>>>>> It sounds like you got a proper hash (you need to redirect that screen
>>>> output to a file) and the warning you got later is probably from some
>>>>> other (not encrypted) file in the archive. Perhaps you accidentally
>>>> added a non-encrypted version to the archive? Try extracting it...
>>>>
>>>> There's definitely only a single file - wallet.dat - in the archive, so
>>>> this is a little puzzling. I'm not sure how adding a password with AES-256
>>>> encryption works - I assume encrypts just the file after compression?
>>>>
>>>>> What does "zipinfo <file>" or similar tool say? Or just "zip -l
>>>> <file>".
>>>>
>>>> I don't have zipinfo (I'm on Windows), but I could download a bootable
>>>> Linux distribution if that would help. 7zip itself gives some info about
>>>> the compressed file:
>>>>
>>>> - attributes: An
>>>> - Encrypted: +
>>>> - Method: AES-256 Deflate
>>>>
>>>> (There's some other stuff about file size, dates, etc, but assume it's
>>>> the encryption info that's needed?)
>>>>
>>>> Many thanks
>>>> Jasper
>>>>
>>>>
>>>>
>>>> On Tue, 15 Sep 2020 at 23:10, magnum <john.magnum@...hmail.com> wrote:
>>>>
>>>>> On 2020-09-15 19:43, Jasper Jones wrote:
>>>>>> I'm reasonably certain the password contains two or three main
>>>>> components,
>>>>>> selected from a couple of words and a long number, linked with some
>>>>>> combination of punctuation.
>>>>>
>>>>> Try adding all such components, one on each line, to a short wordlist
>>>>> eg. "components.txt". Add punctuation and numbers (either simply digits
>>>>> 0 through 9 on separate lines, or/and longer numbers like 2020 if you
>>>>> know them) as well, on separate lines. Then use PRINCE mode.
>>>>>
>>>>>> The first issue is that I believe I need to use zip2john.exe to get
>>>>> the
>>>>>> hash from the zip file. It spits out a very long string of data,
>>>>> starting
>>>>>> with $zip2$, but ends with a message saying that
>>>>> "wallet.zip/wallet.dat is
>>>>>> not encrypted, or stored with a non-handled compression type".
>>>>>
>>>>> What does "zipinfo <file>" or similar tool say? Or just "zip -l <file>".
>>>>>
>>>>> It sounds like you got a proper hash (you need to redirect that screen
>>>>> output to a file) and the warning you got later is probably from some
>>>>> other (not encrypted) file in the archive. Perhaps you accidentally
>>>>> added a non-encrypted version to the archive? Try extracting it...
>>>>>
>>>>>> I wondered whether I needed to use the 7z2john.pl (a perl script?),
>>>>> given I
>>>>>> used 7-zip to generate the encrypted file?
>>>>>
>>>>> No, if it's zip format, zip2john is needed.
>>>>>
>>>>> zip2john archive.zip > hashfile.txt
>>>>> john hashfile.txt --prince=components.txt
>>>>>
>>>>> magnum
>>>>>
>>>>>
>
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