Crunch!

Since I love how Crunch works, I will make a tutorial on how to use it :-)

To install it, download the Crunch http://sourceforge.net/projects/crunch-wordlist/

cd /path/to/downloaded/archive
tar -xvf crunch_archive.tgz
cd /path/to/extracted/folder/
sudo make && make install

Troubleshooting:

If you get this error:

Building binary...
/usr/bin/gcc -Wall -lm -pthread -std=c99  crunch.c -o crunch
crunch.c: In function ‘PrintPercentage’:
crunch.c:1006:20: warning: variable ‘finall’ set but not used [-Wunused-but-set-variable]
crunch.c: In function ‘renamefile’:
crunch.c:1032:12: warning: variable ‘pidret’ set but not used [-Wunused-but-set-variable]
crunch.c: In function ‘main’:
crunch.c:1805:8: warning: variable ‘loaded’ set but not used [-Wunused-but-set-variable]
/tmp/ccqWIgti.o: In function `count_strings':
crunch.c:(.text+0x1c1e): undefined reference to `pow'
crunch.c:(.text+0x1dd5): undefined reference to `pow'
crunch.c:(.text+0x1fd1): undefined reference to `pow'
collect2: ld returned 1 exit status
make: *** [crunch] Error 1

Then the math librarys aren't included, to fix it, simply run this command:

# /usr/bin/gcc -Wall -lm -pthread -std=c99 -m32 -D_LARGEFILE_SOURCE -D_FILE_OFFSET_BITS=64 crunch.c -o crunch -lm
[If you are on 64-bit platform, change "-m32" to "-m64"]

Crunch generates wordlist out of a characterset that you give it. F. ex.

./crunch 8 8 0123456789 -o 8Digit.ls

This will launch Crunch, make a wordlist named 8Digit.lst, only 8 character words, and the characterset is 0-9.

A neat little feature with Crunch, is that it displays the amount of words it will generate, how much space the wordlist will use and it has a sleep timer of 3 seconds, so if the wordlist is to big you can stop Crunch.

Crunch has the following options:

-b  Maximum bytes to write per file, so using this option the wordlist to be created can be split into various
      sizes such as KB / MB / GB (must be used in combination with "-o START" switch)
-c  Number of lines to write to output file, must be used together with "-o START"
-d  Limits the number of consecutive identical characters (crunch v3.2)
-e Specifies when crunch should stop early (crunch v3.1)
-f  Path to the charset.lst file to use, standard location is '/pentest/passwords/crunch/charset.lst
    to be used in conjunction with the name of the desired charset list, such as 'mixalpha-numeric-space'
-i  Inverts the output sequence from left-to-right  to  right-to-left
    (So instead of aaa, aab, aac, aad etc, output would be aaa baa caa daa)
-l  When specifying custom patterns with the -t option, the -l switch allows you to identify which of the characters
    should be taken as a literal character instead of a place holder ( @,%^ )
-o  Allows you to specify the file name / location for the output, e.g. /media/flashdrive/wordlist.txt
-p  Prints permutations of the words or characters provided in the command line.
-q  Prints permutation of the words or characters found in a specified file
-r  Resumes from a previous session, exact same syntax to be used followed by -r
-s  Allows you to specify the starting string for your wordlist.
-t  Allows you to specify a specific pattern to use. Probably one of the most important functions !
     Place holders for fixed character sets are ;
     @   --  lower case alpha characters
     ,    --   upper case alhpa characters
     %   --  numeric characters
    ^    --  special characters (including space)
-u  Supresses the output of wordlist size & linecount prior starting wordlist generation.
-z  Adds support to compress the generation output, supports gzip, bzip & lzma

If you are creating big wordlists, Crunch also supports compression in gzip, bzip2 and lzma.

./crunch 6 6 0123456789 -o 8Digit.lst -z lzma













Also another neat feature, is that you can pipe the outputs of Crunch to AirCrack-ng for example.

./crunch 8 8 0123456789 | aircrack-ng -e test -w - capture.cap
[Little picturefail here, I used the command mentioned above.]

This one is a little crazy :-P






To learn more about Crunch, in terminal, type "man crunch".