Threaded Password Cracker

Project Overview

This project is a multi-threaded password-cracking application written in C. The primary focus of the project is to demonstrate performance improvements using multiple threads while working with hashed passwords.

Features

• Uses PThreads for multi-threading.
• Supports various hashing algorithms, including DES, NT, MD5, SHA-256, SHA-512, bcrypt, and yescrypt.
• Capable of processing up to 24 threads for password cracking. (Self imposed limit of 24 threads)
• Provides verbose mode for detailed diagnostics.
• Outputs cracked passwords or failures along with performance metrics.

Command-Line Options

The program accepts the following command-line arguments:

Option	Description
-i	Specifies the input file containing hashed passwords (required).
-o	Specifies the output file for results (default: stdout).
-d	Specifies the dictionary file with plaintext words (required).
-t	Specifies the number of threads to use (default: 1; maximum: 24).
-v	Enables verbose mode for detailed processing diagnostics.
-h	Displays help text about command-line options.
-n	Applies the nice() function to lower the priority of the running process.

Implementation Details

• The program utilizes crypt_rn() for thread-safe cryptographic operations.
• Mutexes are used to handle shared resources, ensuring thread safety during operations like output writing and global variable updates.
• The program dynamically balances the load among threads.
• Outputs the performance of each thread, including processing time, number of hashes processed, and failure count.

File Structure

• thread_hash.c: Contains the main logic and functions for the program.
• thread_hash.h: Defines constants, data structures, and utility macros.
• Makefile: Automates compilation and cleanup.
• Input files:
  • passwords*.txt: Files containing hashed passwords. Each file (e.g., passwords100.txt, passwords500.txt) corresponds to a specific set of hashed passwords.
  • plain*.txt: Files containing plaintext words to be used as a dictionary for cracking passwords. Each file (e.g., plain100.txt, plain500.txt) corresponds to its respective passwords*.txt file.

Notes on Input Files:

• Files with the same number (e.g., passwords100.txt and plain100.txt) must always be used together for accurate results. The passwords*.txt file contains hashed versions of passwords that are expected to match entries in the corresponding plain*.txt file.
• The passwords*.txt file must be passed in using the -i flag, and the corresponding plain*.txt file must be passed in using the -d flag.
• The -o flag is optional. If it is not specified, the output will be displayed in the terminal (stdout). Specifying -o will redirect the output to a specified file.

Compilation and Execution

1. Compile the program using the provided Makefile:

   make

2. Run the program with appropriate options. Example:

   ./thread_hash -i passwords100.txt -d plain100.txt -t 4 -o output.txt -v

Output Format

Cracked Passwords

cracked  <plaintext_password>  <hashed_password>

Failed Passwords

*** failed to crack  <hashed_password>

Thread Summary (to stderr)

total:  4   10.23 sec   DES: 10   NT: 15   MD5: 5   SHA256: 20   SHA512: 10   YESCRYPT: 8   total: 100  failed: 5

Example Use Case

1. Input files: passwords100.txt (hashed passwords) and plain100.txt (plaintext dictionary).
2. Run the program with 4 threads:

   ./thread_hash -i passwords100.txt -d plain100.txt -t 4 -o results.txt

3. View the results in results.txt and performance metrics in the terminal.