The technique used to guard an encrypted or hashed password determines whether one can decode or reverse it. The following points will help you understand the procedure:
1. Understand the Encryption/Hashing Method
Before proceeding, identify the format of the password.
- Encryption: Reversible using the correct decryption key (e.g., AES, RSA).
- Hashing: Irreversible by design (e.g., MD5, SHA-256).
2. Methods to Reverse or Crack Passwords
For Encrypted Passwords
- Use the correct decryption algorithm and key.
- Example: If encrypted with AES-256, you'll need the algorithm, key, and initialization vector (IV).
- Tools:
- OpenSSL: Command-line decryption for encrypted data.
- CyberChef: Web-based tool for encryption and decryption.
For Hashed Passwords
Since hashes are one-way, you can't "decrypt" them, but you can try these methods:
-
Rainbow Table Attacks
- Use precomputed tables of hashes and plaintext values to find matches.
- Tools:
- RainbowCrack
- Ophcrack (for Windows passwords)
-
Brute Force
- Generate all possible plaintext values and compare their hashes.
- Tools:
-
Dictionary Attacks
- Use a list of common passwords or phrases to find the match.
- Tools: Same as brute force tools.
-
Credential Lookup
- Search databases of leaked credentials for matches.
- Services:
- Have I Been Pwned
- DeHashed
3. Using Tools and Scripts
Here are some helpful tools/scripts for cracking passwords:
- Hashcat: A GPU-accelerated hash cracker.
hashcat -m <hash type> -a <attack mode> hashfile wordlist
- John the Ripper: A versatile password cracker.
john --format=<hash format> --wordlist=<wordlist> hashfile
- CyberChef: Perform various decoding and encryption operations interactively.
