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hashcat - Advanced Password Recovery ​

hashcat is the world's fastest and most advanced password recovery tool, supporting over 200 highly-optimized hashing algorithms. It's designed to crack password hashes using various attack modes and can utilize CPU, GPU, and other hardware accelerators.

🎯 Purpose ​

  • Password Cracking: Recover passwords from hash values
  • Hash Analysis: Identify and analyze different hash types
  • Security Testing: Test password strength and policies
  • Forensics: Recover passwords from seized systems

🚀 Basic Usage ​

Hash Identification ​

bash
# Identify hash type
hashcat --help | grep -i "hash modes"
hashid hash.txt

# Example hash modes
# MD5: -m 0
# SHA1: -m 100
# NTLM: -m 1000
# bcrypt: -m 3200

Basic Attacks ​

bash
# Dictionary attack
hashcat -m 0 -a 0 hash.txt rockyou.txt

# Brute force attack
hashcat -m 0 -a 3 hash.txt ?a?a?a?a?a?a

# Combination attack
hashcat -m 0 -a 1 hash.txt dict1.txt dict2.txt

🔧 Attack Modes ​

Dictionary Attack (-a 0) ​

bash
# Basic dictionary attack
hashcat -m 1000 ntlm_hashes.txt /usr/share/wordlists/rockyou.txt

# With rules
hashcat -m 1000 -r /usr/share/hashcat/rules/best64.rule ntlm_hashes.txt rockyou.txt

# Multiple wordlists
hashcat -m 0 hashes.txt wordlist1.txt wordlist2.txt

Combination Attack (-a 1) ​

bash
# Combine two wordlists
hashcat -m 0 -a 1 hashes.txt left.txt right.txt

# Example: passwords like "password123", "admin2021"
hashcat -m 0 -a 1 hashes.txt words.txt numbers.txt

Brute Force Attack (-a 3) ​

bash
# Mask attack - 8 character alphanumeric
hashcat -m 0 -a 3 hashes.txt ?a?a?a?a?a?a?a?a

# Custom mask for "password" + 4 digits
hashcat -m 0 -a 3 hashes.txt password?d?d?d?d

# Increment mode (try lengths 1-8)
hashcat -m 0 -a 3 --increment --increment-min 1 --increment-max 8 hashes.txt ?a?a?a?a?a?a?a?a

Hybrid Attacks (-a 6, -a 7) ​

bash
# Hybrid wordlist + mask (password123)
hashcat -m 0 -a 6 hashes.txt wordlist.txt ?d?d?d

# Hybrid mask + wordlist (123password)
hashcat -m 0 -a 7 hashes.txt ?d?d?d wordlist.txt

🎯 Common Hash Types ​

bash
# MD5
hashcat -m 0 hashes.txt wordlist.txt

# SHA1
hashcat -m 100 hashes.txt wordlist.txt

# NTLM (Windows)
hashcat -m 1000 ntlm.txt wordlist.txt

# bcrypt
hashcat -m 3200 bcrypt.txt wordlist.txt

# WPA/WPA2
hashcat -m 2500 capture.hccapx wordlist.txt

# PDF documents
hashcat -m 10400 pdf.hash wordlist.txt

# ZIP archives
hashcat -m 13600 zip.hash wordlist.txt

📁 Installation ​

Debian/Ubuntu ​

bash
sudo apt update
sudo apt install hashcat

From Official Repository ​

bash
# Download from https://hashcat.net/hashcat/
wget https://hashcat.net/files/hashcat-6.2.6.tar.gz
tar -xzf hashcat-6.2.6.tar.gz
cd hashcat-6.2.6
make
sudo make install

⚙️ Performance Optimization ​

GPU Acceleration ​

bash
# Use all available GPUs
hashcat -m 0 -a 0 -O hashes.txt wordlist.txt

# Specify GPU devices
hashcat -m 0 -a 0 -d 1,2 hashes.txt wordlist.txt

# Benchmark mode
hashcat -b

Workload Tuning ​

bash
# Adjust workload profile (1=low, 2=default, 3=high, 4=nightmare)
hashcat -m 0 -a 0 -w 3 hashes.txt wordlist.txt

# Manual tuning
hashcat -m 0 -a 0 -n 80 -u 1024 hashes.txt wordlist.txt

💡 Pro Tips ​

Rule-Based Attacks ​

bash
# Use built-in rules
hashcat -m 0 -r /usr/share/hashcat/rules/best64.rule hashes.txt wordlist.txt

# Multiple rules
hashcat -m 0 -r rule1.rule -r rule2.rule hashes.txt wordlist.txt

# Generate custom rules
# Create rules to append years, capitalize, etc.

Session Management ​

bash
# Create named session
hashcat -m 0 -a 0 --session mysession hashes.txt wordlist.txt

# Restore session
hashcat --restore --session mysession

# Show session status
hashcat --show --session mysession

Mask Files ​

bash
# Create mask file for common patterns
echo "?u?l?l?l?l?l?d?d" > masks.txt
echo "?l?l?l?l?d?d?d?d" >> masks.txt
hashcat -m 0 -a 3 hashes.txt masks.txt

🚨 Important Notes ​

  • Legal Use Only: Only crack passwords you own or have explicit permission to test
  • GPU Memory: Large wordlists may require significant GPU memory
  • Heat Management: Extended GPU usage generates significant heat
  • Power Consumption: High-performance cracking consumes substantial power
  • Results Storage: Use --show to display previously cracked passwords

🔍 Hash Extraction ​

Common tools for extracting hashes:

  • john: For various file formats
  • samdump2: For Windows SAM files
  • ophcrack: For Windows LM/NTLM hashes
  • hash-identifier: For identifying hash types

Part of the HackerHub.me tool documentation series