crunch

CRUNCH – Word List Generator

Crunch is a Linux Tool used to create wordlist that can be used for Password Escalation or Brute Force purposes. Crunch gives many options to customize the Word List you want. Word List can have different Combinations of Character Sets like alphabets both lowercase and uppercase, numbers 0-9, Symbols, Spaces. The output of the wordlist can be obtained as file or to another program.
The order which should be specified in command Line must be – lower case characters, upper case
characters, numbers, and then symbols.  If the sequence is not followed , the desired result in word list will not be the output. The space character can be included in wordlist, it should be included with escape sequence using \ character. or enclose character in quotes like “ethical “, notice the space after ethical. The length of words can also be specified both minimum word length and maximum word length.

 

DESCRIPTION
Crunch can create a word-list based on criteria you specify. The output
from crunch can be sent to the screen, file, or to another program.
The required parameters are:

min-len
The minimum length string you want crunch to start at. This
option is required even for parameters that won’t use the value.

max-len
The maximum length string you want crunch to end at. This
option is required even for parameters that won’t use the value.

charset string
You may specify character sets for crunch to use on the command
line or if you leave it blank crunch will use the default
character sets. The order MUST BE lower case characters, upper
case characters, numbers, and then symbols. If you don’t follow
this order you will not get the results you want. You MUST
specify either values for the character type or a plus sign.
NOTE: If you want to include the space character in your
character set you must escape it using the \ character or
enclose your character set in quotes i.e. “abc “. See the
examples 3, 11, 12, and 13 for examples.

CRUNCH SYNTAX

 

How To Generate Word List: Crunch Options
Crunch creates word-list based on different criteria specified. Output of Crunch can be stored in a File as word list, can be used directly by other programs or printed on screen.
The basic  parameters are:

min-len  minimum word length.
max-len maximum word length
charset string character set you want to use to generate word list like uppercase or lowercase or numbers or symbols or their combinations. If we leave character set option blank and dont specify it, crunch will use default character set. The order MUST BE lower case characters, upper case characters, numbers, and then symbols. To include the space character in your
character set you must escape it using the \ character or
enclose your character set in quotes i.e. “abc “. See the
examples 3, 11, 12, and 13 for examples.

OPTIONS
-b number[type] size of the output file, only works if -o START is
used, i.e.: 60MB The output files will be in the format of
starting letter-ending letter for example: ./crunch 4 5 -b 20mib
-o START will generate 4 files: aaaa-gvfed.txt, gvfee-ombqy.txt,
ombqz-wcydt.txt, wcydu-zzzzz.txt valid values for type are kb,
mb, gb, kib, mib, and gib. The first three types are based on
1000 while the last three types are based on 1024. NOTE There
is no space between the number and type. For example 500mb is
correct 500 mb is NOT correct.

-c number
Specifies the number of lines to write to output file, only
works if -o START is used, i.e.: 60 The output files will be in
the format of starting letter-ending letter for example:
./crunch 1 1 -f /pentest/password/crunch/charset.lst mixalpha-
numeric-all-space -o START -c 60 will result in 2 files: a-7.txt
and 8-\ .txt The reason for the slash in the second filename
is the ending character is space and ls has to escape it to
print it. Yes you will need to put in the \ when specifying the
filename because the last character is a space.

-d numbersymbol
Limits the number of duplicate characters. -d 2@ limits the
lower case alphabet to output like aab and aac. aaa would not
be generated as that is 3 consecutive letters of a. The format
is number then symbol where number is the maximum number of
consecutive characters and symbol is the symbol of the the
character set you want to limit i.e. @,%^ See examples 17-19.

-e string
Specifies when crunch should stop early

-f /path/to/charset.lst charset-name
Specifies a character set from the charset.lst

-i Inverts the output so instead of aaa,aab,aac,aad, etc you get
aaa,baa,caa,daa,aba,bba, etc

-l When you use the -t option this option tells crunch which symbols
should be treated as literals. This will allow you to use the
placeholders as letters in the pattern. The -l option should be
the same length as the -t option. See example 15.

-m Merged with -p. Please use -p instead.

-o wordlist.txt
Specifies the file to write the output to, eg: wordlist.txt

-p charset OR -p word1 word2 …
Tells crunch to generate words that don’t have repeating
characters. By default crunch will generate a wordlist size of
#of_chars_in_charset ^ max_length. This option will instead
generate #of_chars_in_charset!. The ! stands for factorial.
For example say the charset is abc and max length is 4.. Crunch
will by default generate 3^4 = 81 words. This option will
instead generate 3! = 3x2x1 = 6 words (abc, acb, bac, bca, cab,
cba). THIS MUST BE THE LAST OPTION! This option CANNOT be used
with -s and it ignores min and max length however you must still
specify two numbers.

-q filename.txt
Tells crunch to read filename.txt and permute what is read.
This is like the -p option except it gets the input from
filename.txt.

-r Tells crunch to resume generate words from where it left off. -r
only works if you use -o. You must use the same command as the
original command used to generate the words. The only exception
to this is the -s option. If your original command used the -s
option you MUST remove it before you resume the session. Just
add -r to the end of the original command.

-s startblock
Specifies a starting string, eg: 03god22fs

-t @,%^
Specifies a pattern, eg: @@god@@@@ where the only the @’s, ,’s,
%’s, and ^’s will change.
@ will insert lower case characters
, will insert upper case characters
% will insert numbers
^ will insert symbols

-u
The -u option disables the printpercentage thread. This should
be the last option.

-z gzip, bzip2, lzma, and 7z
Compresses the output from the -o option. Valid parameters are
gzip, bzip2, lzma, and 7z.
gzip is the fastest but the compression is minimal. bzip2 is a
little slower than gzip but has better compression. 7z is
slowest but has the best compression.

EXAMPLES
Example 1

crunch will print wordlist that starts at a and ends at zzzzz to a file called 18.txtScreenshot from 2016-03-16 13-46-07

Example 2

crunch will display a wordlist using the character set abcde that
starts at a and ends at eeeee

crunch tutorial 2
crunch tutorial 2

Example 3

there is a space at the end of the character string. In order for
crunch to use the space you will need to escape it using the \
character. In this example you could also put quotes around the
letters and not need the \, i.e. “abcde “. Crunch will display a
wordlist using the character set abcde that starts at a and ends at
(5 spaces)

crunch tutorial example 3
crunch tutorial example 3

Example 4

crunch will use the mixalpha-numeric-all-space character set from
charset.lst and will write the wordlist to a file named wordlist.txt.
The file will start with a and end with ” ”

Example 5
crunch 8 8 -f charset.lst mixalpha-numeric-all-space -o wordlist.txt -t
@@dog@@@ -s cbdogaaa
crunch should generate a 8 character wordlist using the mixalpha-
number-all-space character set from charset.lst and will write the
wordlist to a file named wordlist.txt. The file will start at cbdogaaa
and end at ” dog ”

Example 6

crunch with start generating a wordlist at BB and end with ZZZ. This
is useful if you have to stop generating a wordlist in the middle.
Just do a tail wordlist.txt and set the -s parameter to the next word
in the sequence. Be sure to rename the original wordlist BEFORE you
begin as crunch will overwrite the existing wordlist.

Example 7

The numbers aren’t processed but are needed.
crunch will generate abc, acb, bac, bca, cab, cba.

Example 8

The numbers aren’t processed but are needed.
crunch will generate birdcatdog, birddogcat, catbirddog, catdogbird,
dogbirdcat, dogcatbird.

Example 9

crunch will generate bzip2 compressed files with each file containing
6000 words. The filenames of the compressed files will be first_word-
last_word.txt.bz2

# time ./crunch 1 4 -o START -c 6000 -z gzip
real 0m2.729s
user 0m2.216s
sys 0m0.360s

# time ./crunch 1 4 -o START -c 6000 -z bzip2
real 0m3.414s
user 0m2.620s
sys 0m0.580s

# time ./crunch 1 4 -o START -c 6000 -z lzma
real 0m43.060s
user 0m9.965s
sys 0m32.634s

size filename
30K aaaa-aiwt.txt
12K aaaa-aiwt.txt.gz
3.8K aaaa-aiwt.txt.bz2
1.1K aaaa-aiwt.txt.lzma

Example 10

will generate 4 files: aaaa-gvfed.txt, gvfee-ombqy.txt, ombqz-
wcydt.txt, wcydu-zzzzz.txt
the first three files are 20MBs (real power of 2 MegaBytes) and the
last file is 11MB.

Example 11

will generate a 3 character long word with a character as the first
character, and number as the second character, and a symbol for the
third character. The order in which you specify the characters you
want is important. You must specify the order as lower case character,
upper case character, number, and symbol. If you aren’t going to use a
particular character set you use a plus sign as a placeholder. As you
can see I am not using the upper case character set so I am using the
plus sign placeholder. The above will start at a1! and end at c3#

Example 12

will generate 3 character words starting with !1a and ending with #3c

Example 13

the plus sign (+) is a place holder so you can specify a character set
for the character type. crunch will use the default character set for
the character type when crunch encounters a + (plus sign) on the
command line. You must either specify values for each character type
or use the plus sign. I.E. if you have two characters types you MUST
either specify values for each type or use a plus sign. So in this
example the character sets will be:
abcdefghijklmnopqrstuvwxyz
ABCDEFGHIJKLMNOPQRSTUVWXYZ
123
!@#$%^&*()-_+=~`[]{}|\:;”‘<>,.?/
there is a space at the end of the above string
the output will start at 11a! and end at “33z “. The quotes show the
space at the end of the string.

Example 14

any character other than one of the following: @,%^
is the placeholder for the words to permute. The @,%^ symbols have the
same function as -t.
If you want to use @,%^ in your output you can use the -l option to
specify which character you want crunch to treat as a literal.
So the results are
birdcatdogaa
birdcatdogab
birdcatdogac
<skipped>
dogcatbirdzy
dogcatbirdzz

Example 15

crunch will now treat the @ symbol as a literal character and not
replace the character with a uppercase letter.
this will generate
p@ssA0!
p@ssA0@
p@ssA0#
p@ssA0$
<skipped>
p@ssZ9

Example 16

crunch will generate 5 character strings starting with @4#S2 and ending
at @8 Q2. The output will be broken into 10KB sized files named for
the files starting and ending strings.

Example 17

crunch will generate 5 character strings staring with aab00 and ending
at zzy99. Notice that aaa and zzz are not present.

Example 18

crunch will generate 10 character strings starting with aab!0001!! and
ending at zzy 9998 The output will be written to 20mb files.

Example 19

crunch will generate 8 characters that limit the same number of lower
case characters to 2. Crunch will start at aabaabaa and end at
zzyzzyzz.

Example 20

crunch will load some Japanese characters from the unicode_test
character set file. The output will start at @日00 and end at @語99.

REDIRECTION
You can use crunch’s output and pipe it into other programs. The two
most popular programs to pipe crunch into are: aircrack-ng and airolib-
ng. The syntax is as follows:

 

 

 

 

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