To perform Dictionary or Bruteforce attacks we need some dictionary files called word lists. These can be created using Crunch which is pre-installed in Kali Linux.
We can also install it in the Termux app in mobile by command pkg install crunch.

Simple wordlist creation

The syntax to create wordlist using the crunch is
 crunch <min no. of characters> <max no. of characters> [options] 

Ex: crunch 2 4  

This will print a simple wordlist with all the combinations of both the alphabets and the numbers starting from 2 letters to 4 letters.

Creating wordlist with specific characters

Ex: crunch 2 4 ABCDEFabcdefgh1234567890 

This will print a simple wordlist with all the combinations with the given characters starting from 2 letters to 4 letters.

Saving wordlist in a file (-o)

To save the wordlist in a file we need to use -o <file path> at the end of the command
Ex: crunch 4 4 abcd0123456 -o wordlist.txt 

It saves the word in the file named wordlist.txt in the directory where we run the command in termux. for example, if we run it in Desktop it will be saved in the Desktop. We can also specify a specific path like /root/Desktop/list/wordlist.txt

Creating wordlist in a specific order (-t)

This is most important in this tutorial.
We use -t to create in a specific order/pattern

USING -t OPTION:

  • @ will insert lower case characters
  • , will insert upper case characters
  • % will insert numbers
  • ^ will insert symbols
Ex: crunch 8 8 -t ,,,,19%% -o acard.txt 

It is used to crack the passwords of the aadhar card pdf. It creates a passwords list with 8 Characters and First 4 Letters with Alphabets with all capital letters and next 2 letters 19 for every line of password and the next 2 letters are total (0-9)numbers.
 

References:

https://www.securitynewspaper.com/2018/11/28/create-your-own-wordlist-with-crunch/