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Trouble with veracrypt volume - holliscat - 01-10-2018

I'm desperately trying to get back into a veracrypt volume I created that has all my cryptocurrency passwords in it. 

I'm new to this and I don't think I fully understand what I need to do. 

The veracrypt volume is a container file rather than a drive, and I know the password is composed of a limited number of "words"/components. so something like "sun7CRABforkBUM" I know all the possible components but not which order or how many, so it could be as little as 5 components or as many as 10, but only from a predefined list, with any word potentially capitalised or not

As far as I could tell, it was a combinator attack I needed to use, so I tried this:

hashcat64.exe -m 13721 -a 1 "s:\crypto" "S:\Downloads\hashcat-4.0.1\crypto.dict"


where "crypto" is the name of my veracrypt volume and "crypto.dict" is a list of all possible password components. 

When I try and run this command I get the usage example prompt. If I try with mode 0 then it says no hash file.

Can anyone tell me what I'm doing wrong here?


RE: Trouble with veracrypt volume - Chick3nman - 01-10-2018

Well, first i would start by suggesting you use something like Prince or another external candidate generator for this since the built in combinator mode doesnt support more than 2 elements at a time. Second, if you are going to use combinator, you need to specify 2 dictionaries, or the same dictionary twice. You have only specified it once in your example.


RE: Trouble with veracrypt volume - holliscat - 01-10-2018

Cool, so say I use prince to generate a list of candidates, am I right in pointing hashcat to the veracrypt volume and the candidate list or do I need to do more than that?

I've read conflicting info about using the veracrypt file vs a hash file. In honesty I have no idea how to generate a hash file if I need to.


RE: Trouble with veracrypt volume - Chick3nman - 01-10-2018

You simply need the first 512bytes of the volume i believe, as it contains the volume header with all the information related to the KDF and the password.


RE: Trouble with veracrypt volume - holliscat - 01-10-2018

Now that sounds simple but I genuinely don't know how to create a file containing only the first 512 bytes. Is there a command I can use to do this?

I'm on windows but I have a linux VM I can do this in.


RE: Trouble with veracrypt volume - holliscat - 01-10-2018

I actually managed to get the first 512 bytes ok using dd.

Now when I try and run it gives me the following error:

Hash 's:\examplecat.vc': Hash-file exception
No hashes loaded.

pp64 < crypto.dict | hashcat64.exe -m 13721 -a 0 "s:\ddoutput.hash"

In this attempt I actually tried again and used the example hash from the wiki to see if it was my data and I get the same error. Have I used the wrong syntax or options?


RE: Trouble with veracrypt volume - Chick3nman - 01-10-2018

That means it doesnt like the path you have provided to the hash files. I would suggest putting them in the same folder as hashcat and trying again.


RE: Trouble with veracrypt volume - holliscat - 01-10-2018

Crap, I can't believe it was that simple. Thanks for all the help!


RE: Trouble with veracrypt volume - holliscat - 01-11-2018

So I got it working with prince and it's working at it, but I realised it's not as efficient as it could be. I realised the structure of the password could be used here but I'm not too sure how.

The password is made up of 10-16 words and each word is used only once, from a predefined list, in order. So if we imagine a spreadsheet with 16 columns, the password would be composed of one word from each column. Each column would contain no more than 10-15 words each.

Would there be a way for me to implement this in hashcat as a rule, or alternatively generate an exhaustive list of candidates and then do a simple dictionary attack?


RE: Trouble with veracrypt volume - philsmd - 01-11-2018

Ha. This is an interesting discussion.

We actually already had a couple of similar topics and discussions on this forum.

It's interesting that some people do not realize how many possibilities of combining x words exist.

The short answer is: given even a small amount of words x and a list of passphrase that all need to contain n words, the combination of each and every word (even with the "small" restriction that words can't be present within the passphrase more than once) is huge and grows almost exponentially with both x and n.

Actually the simplified mathematical formula should look something like this:
1. given x different words
2. given that the passphrase must consist of *exactly* n words

x-0 * x-1 * x-2 * x-3 ... x-k (where the value k is n-1 and therefore the counter "i" goes from 0 to k)

an example: x = 11, n = 10
therefore we compute k = 10 - 1 = 9 (therefore the last number in the formula is x-k = 11-9=2)

11 * 10 * 9 * 8 * 7 * 6 * 5 * 4 * 3 * 2

(as you can see we have n = 10 numbers within the multiplication... some might also notice that this looks very close to the factorial and it does! in general, you just need to substract the remaining combinations if x > n)

You can also think like this: For the first word you can choose all different words x, for the second one (i think you called it "column") you can choose any word except the one that was choosen previously, for the third column you can only pick the remaining ones (all minus the 2 previous ones) etc...

As already mentioned, the number of combinations growths very fast when x and/or n increase.

This of course is a simplified formula and you added this additional requirement:
- generate also the capitalized variant of each word (but do not allow the same capitalized and non-capitalized word within the same passphrase)

This almost doubles the value x (the number of words), but not always/exactly because there could be some words that can't be capitalized (e.g. if they start with a symbol or number etc) and we need to substract (or let's say "filter out") also the number of words that are not allowed because the same capitalized and non-capitalized word can't occur within the same passphrase (as you can see this makes the formula a little bit more complicated... still the limitation/filtering does only eliminate a small subset of the candidates, it's almost negligible).

The idea of combining x words was already explained, for instance here: https://hashcat.net/forum/thread-7131-post-38278.html#pid38278

As you can see, even with "only" n = 4 words (but admittedly a high value of x = 1500) the list of password candidates is very huge (in that case it was almost exactly: 1500 * 1499 * 1498 * 1497 = 5042274741000 combinations)

Now let's speak about how you would write the code to generate such password candidates:
it would be very similar to the example mentioned here: https://hashcat.net/forum/thread-7131-post-38278.html#pid38278 ... BUT with the exception that you have freaking 10 (or even 16) nested loops and the additional code needed to also try the capitalized and non-capitalized version (but only if they are not the same and the additional restriction that it is not allowed to have the same word within a passphrase both in the capitalized and non-capitalized variant Wink ).

As you can see, this would make the code a little bit complicated! Already the 10 nested loops would be quite horrible to code and see!

You could however come up with a recursive version of it, something like this (perl code):
Code:
#!/usr/bin/env perl

# Author: philsmd
# Date: January 2018
# License: public domain (CC0)

use strict;
use warnings;

#
# CONSTANTS
#

my $WORDS_IN_PASSPHRASE = 10;

#
# Example
#

my @LOWER_CASE_WORDS = (
  "this",
  "is",
  "the",
  "list",
  "of",
  "words",
  "that",
  "you",
  "want",
  "to",
  "try",
);

my $AMOUNT_OF_WORDS = scalar (@LOWER_CASE_WORDS);

#
# Helper functions
#

# normally we would just print it, but we need to also print the variants with capitalized (upper cased first letter):

sub print_passphrase
{
  my $recursive_step = shift;
  my $words_in_pass  = shift;
  my $passwords      = shift;

  if ($recursive_step < 1)
  {
    for (my $i = 0; $i < $WORDS_IN_PASSPHRASE; $i++)
    {
      print @$passwords[$i];
    }

    print "\n";
  }
  else
  {
    my $loop_index = $WORDS_IN_PASSPHRASE - $recursive_step;
    my $word_index = @$words_in_pass[$loop_index];

    my $pass = $LOWER_CASE_WORDS[$word_index];


    # always generate the lower-case variant:

    my @tmp_passwords = @$passwords;

    push (@tmp_passwords, $pass);

    print_passphrase ($recursive_step - 1, $words_in_pass, \@tmp_passwords);



    # upper-case (capitalized) variant (if needed):

    my $pass_capitalized = ucfirst ($pass);

    if ($pass_capitalized ne $pass)
    {
      my @tmp_passwords_capitalized = @$passwords;

      push (@tmp_passwords_capitalized, $pass_capitalized);

      print_passphrase ($recursive_step - 1, $words_in_pass, \@tmp_passwords_capitalized);
    }
  }
}

sub generate_word_list
{
  my $recursive_step = shift;
  my $words_in_pass  = shift;

  if ($recursive_step < 1)
  {
    my @passwords = ();

    print_passphrase ($WORDS_IN_PASSPHRASE, $words_in_pass, \@passwords);
  }
  else
  {
    # recursive step:

    for (my $i = 0; $i < $AMOUNT_OF_WORDS; $i++)
    {
      # search in array (or use grep):

      my $found = 0;

      foreach my $item (@$words_in_pass)
      {
        if ($item == $i)
        {
          $found = 1;

          last;
        }
      }

      next if ($found == 1);



      # if the word is NOT within the passphrase already:

      # make a copy of the word list:

      my @tmp_words_in_pass = @$words_in_pass;

      # add the new one:

      push (@tmp_words_in_pass, $i);

      generate_word_list ($recursive_step - 1, \@tmp_words_in_pass);
    }
  }
}

#
# Start
#

if ($AMOUNT_OF_WORDS < $WORDS_IN_PASSPHRASE)
{
  print "ERROR: not enough words (the amount is $AMOUNT_OF_WORDS) for the passphrase (of $WORDS_IN_PASSPHRASE words)\n";

  exit (1);
}

my @words_in_pass = ();

generate_word_list ($WORDS_IN_PASSPHRASE, \@words_in_pass);

exit (0);

Note: you could just change the WORDS_IN_PASSPHRASE and LOWER_CASE_WORDS variables to fit your needs (it's quite flexible for any x amount of words in LOWER_CASE_WORDS and value n).

Of course you could argue that running this recursive code might not be the best idea, since it could be slow etc... but actually writing the same thing in a non-recursive way (similar to the code provided here: https://hashcat.net/forum/thread-7131-post-38278.html#pid38278 , but adapted to 10+ words and the capitalized variant) or even writing it with ANSI C etc... might only speed it up by a negligible constant factor.
The real "cost" is to run such a huge amount of combinations. As said, in worst case... where n=x, almost the factorial of the number of capitalized plus non-capitalized words).

Therefore, even if you have a perfect password candidate generator, the total number of combinations might be too huge (depending on x and n).

The short version is: it's not complicated to come up with code for this, but the complexity (the "keyspace", number of password candidates) might be too huge even if you just want to "combine each word from a known set of words".