**Note: The content in this article is only for educational purposes and understanding of cybersecurity concepts. It should enable people and organizations to have a better grip on threats and know how to protect themselves against them. Please use this information responsibly.**
Crunch: A wordlist Generator
- Objectives
- Basic Structure
- Pattern Specific Wordlist
- Permutation
- Break wordlist into chunks
- Wordlist Compression
- Handle frequency of characters
- Inversion of output
Crunch:
Crunch is a wordlist that generates a utility used to create a wordlist using numbers, letters, and symbols. Mostly Hackers, Penetration testers use this tool to create passwords. The crunch comes pre-installed In Kali Linux.
Basic Structure
Crunch <min><max> -o <filename>
Fig1: Basic structure
- min: It is the minimum password length.
- max: It is the maximum password length.
- charset: Character se to be used.
- -o : Output in a textfile, along with name of the text file.
Charset: In charset we have three options
- Default: Uses small alphabet (Fig1).
- User-defined: User defined which charset wants to use.(abc.. , ABC… ,123…, @#$%^*)
- Crunch charset: It has its own charset. If we want to use charset of crunch we have to change directory (/usr/share/crunch) and we fined charset.lst in it.
Crunch charset: Crunch <min><max> -f /usr/share/charset.list mixalpha | more
Pattern specific wordlist
-t: indicates pattern
Scenario 1: Normal condition
- @ – Lowercase
- , – Uppercase
- %- Number
- ^- Symbol
Syntax: Crunch <min><max> path -t //%%(using two upper case letter and 2 Number) below we used only upper case.
Scenario 2: If password is a phone number than
- @ – Lowercase
- , – Uppercase
- %- Number
- ^- Symbol
Syntax: Crunch 10 10 path -t %%%%%%%%%%%(we have to use ten % sign)
Scenario 3: if password length is 7or8 char including name,@ and number
- @ – Lowercase
- , – Uppercase
- %- Number
- ^- Symbol
Syntax: Crunch 7 8 charset -t name@%%% -l aaaa@aaa |more
-l is used so that @ used as it is.
Permutation:
In permutation it used only john, pet and jan to create password
Now saving john, pet, jan and 123 in .txt file.
Break Wordlist into chunks:
It breaks wordlist into two:
- Lines : After limit it creates new file(e.g. if we use 10 as limit than after 10 lines new file creates and this continues till all password over).
- Storage: After limit it creates new file (e.g. if we use 2MB as limit of a file than after 2MB it creates new file).
Wordlist Compression:
For compression we have .gzip .bzip2 .lzma .7z etc.
Handle frequency of characters:
Syntax: crunch 6 6 timtat -d 2@ |more
Inversion of output:
Syntax: crunch 8 8 -t pass@%%% -l aaaa@aaa -I |more
