Lesson 01 · Slide 1
Introduction to Hashcat
A comprehensive introduction to the world's most popular open-source password recovery tool — from basic concepts to your first hash crack.
Learning Objectives
- Understand what Hashcat is and why it exists
- Learn the history and evolution of the tool
- Explore the main capabilities and supported attack types
- Install Hashcat and run basic commands
- Perform a test dictionary attack on a known MD5 hash
Lesson 01 · Slide 2
What Is Hashcat?
Hashcat is an open-source password recovery tool that uses modern hash function recognition methods to recover lost passwords or verify the security of existing ones.
Key Characteristics
- Free and open-source (MIT license)
- Extremely fast — GPU-accelerated
- Supports 350+ hash types
- Cross-platform (Windows, Linux, macOS)
Who Uses It?
- Security researchers — studying password security
- Penetration testers — auditing organizations
- System administrators — verifying password policies
- Forensic analysts — recovering evidence
Notes: Hashcat's primary goal is to recover lost passwords or to verify the security of existing password hashes. It should only be used on systems you own or have written authorization to test.
Lesson 01 · Slide 3
History and Development
Hashcat was created to improve and accelerate the password recovery process. Over the years, it has grown from a simple CPU-based cracker into the most powerful hash recovery tool available.
Key Milestones
- Early versions — CPU-only password recovery tool with limited hash support
- oclHashcat era — Introduction of GPU acceleration using OpenCL, dramatically increasing speed
- Hashcat 3.0+ (2016) — CPU and GPU versions merged into a single unified tool
- Ongoing development — Constant updates adding new hash types and optimizing recognition processes
Open-Source Milestone
In 2015, Hashcat was made fully open-source, allowing the community to contribute hash algorithms, performance optimizations, and bug fixes. This accelerated development significantly.
Lesson 01 · Slide 4
Main Capabilities
Hashcat stands out due to its extensive feature set and broad compatibility across platforms and hardware.
Hardware Acceleration
- CPU (all platforms)
- NVIDIA GPU (CUDA)
- AMD GPU (OpenCL)
- Apple Metal (macOS)
Core Features
- 350+ hash types — MD5, SHA-1, SHA-256, bcrypt, NTLM, WPA, and many more
- Multiple attack modes — dictionary, mask, combinator, rule-based, and hybrid attacks
- Session management — pause, resume, and restore cracking sessions
- Distributed cracking — split workloads across multiple machines
Lesson 01 · Slide 5
Attack Types Overview
Hashcat supports several attack modes, each suited for different scenarios.
| Mode | Flag | Description |
|---|
| Dictionary Attack | -a 0 | Tries every word from a wordlist file |
| Combinator Attack | -a 1 | Combines words from two dictionaries |
| Brute-Force / Mask | -a 3 | Tries all combinations matching a pattern (mask) |
| Hybrid (Dict + Mask) | -a 6 | Appends mask patterns to dictionary words |
| Hybrid (Mask + Dict) | -a 7 | Prepends mask patterns to dictionary words |
Notes: The dictionary attack (-a 0) is the most commonly used starting point. Rule-based attacks add transformations (capitalize, append digits, etc.) to dictionary words, making them extremely powerful.
Lesson 01 · Slide 6
Quick Demo: Your First Crack
Let's walk through cracking a known MD5 hash using a dictionary attack.
Step 1: Create a hash file
# The MD5 hash of "password"
echo "5f4dcc3b5aa765d61d8327deb882cf99" > hashes.txt
Step 2: Run the attack
hashcat -m 0 -a 0 -o cracked.txt hashes.txt example.dict
Step 3: Check results
cat cracked.txt
# Output: 5f4dcc3b5aa765d61d8327deb882cf99:password
Command Breakdown
-m 0 — Hash type: MD5-a 0 — Attack mode: Dictionary-o cracked.txt — Output file for recovered passwordshashes.txt — File containing target hashesexample.dict — Wordlist / dictionary file
Lesson 01 · Slide 7
Essential Commands
Before diving deeper, familiarize yourself with these fundamental Hashcat commands.
System Information
# Show detected compute devices (GPUs, CPUs)
hashcat -I
# Display full help with all options
hashcat --help
Common Flags Reference
| Flag | Purpose | Example |
|---|
-m | Hash type | -m 0 (MD5) |
-a | Attack mode | -a 0 (dictionary) |
-o | Output file | -o results.txt |
--show | Show already cracked | hashcat -m 0 hash.txt --show |
-w | Workload profile | -w 3 (high performance) |
Lesson 01 · Slide 8
Lab & Homework
Lab Exercises
- Install Hashcat on your operating system and verify the installation
- Run basic commands —
hashcat -I and hashcat --help to explore options
- Crack an MD5 hash — perform a dictionary attack on a known hash and verify the output
Homework Tasks
- Research and list 5 hash types supported by Hashcat with their
-m codes
- Explain the difference between dictionary and mask attacks in your own words
- Create and crack your own MD5 hash using a custom wordlist