John the Ripper
Fast password cracking tool supporting many hash formats
Methods10 commands
#password#cracking#hash#bruteforce
Installation
1Install via package manager
2Or build from source
3Verify installation
# Debian/Ubuntu
apt install john
# Verify
john --versionBasic Usage
Crack password hashes using wordlists, rules, and brute force
# Basic cracking
john hash.txt
# Wordlist attack
john --wordlist=rockyou.txt hash.txt
# Show cracked passwords
john --show hash.txtCommand Reference
10 commands
1Use wordlist for dictionary attack
--wordlist2Apply word mangling rules
--rules3Brute force incremental mode
--incremental4Specify hash format
--format5Show cracked passwords
--show6Session name for resuming
--session7Restore interrupted session
--restore8Pot file to use
--pot9Number of parallel processes
--fork10Print words to stdout
--stdoutWhen to Use
1
Password cracking from captured hashes2
Hash type analysis and identification3
CTF challenges requiring hash cracking4
Auditing password policy strength5
Penetration testing post-exploitationNotes & Tips
1
Use --wordlist for dictionary attacks with common passwords2
Use --incremental for brute force on short passwords3
GPU support available with john --devices for faster crackingCommon Errors & Solutions
No hashes loaded
Verify hash format and use --format flag
Wrong format
Check if hashes are in valid format for John
Too slow
Use --fork for multiprocessing or enable GPU