Hashcat: The Complete Guide to Password Cracking (2025)

What is Hashcat?

Hashcat is the world’s fastest and most advanced password recovery tool, supporting five unique attack modes for over 300 highly-optimized hashing algorithms. Unlike other password cracking tools, Hashcat leverages:

• GPU acceleration (NVIDIA, AMD, Intel)
• Multi-hash and multi-OS support
• Distributed cracking networks
• Advanced rule-based attacks
• Automatic performance tuning

Installing Hashcat

Linux Installation

sudo apt update && sudo apt install hashcat -y  # Debian/Ubuntu
sudo dnf install hashcat -y  # Fedora
sudo pacman -S hashcat  # Arch Linux

Windows Installation

Download the binaries from hashcat.net and extract the ZIP file.

Verifying Installation

hashcat --version
# Should return: v6.2.6

Understanding Hash Types

Hashcat supports over 300 hash types. Common ones include:

Basic Hashcat Commands

hashcat -m 0 -a 0 hashes.txt rockyou.txt
# -m 0 = MD5 hash type
# -a 0 = dictionary attack
# hashes.txt = file containing hashes
# rockyou.txt = wordlist

hashcat -m 1000 -a 3 hashes.txt ?a?a?a?a?a?a
# -a 3 = brute-force attack
# ?a = all printable ASCII characters
# ?a?a?a?a?a?a = try all 6-character combinations

Advanced Attack Techniques

1. Rule-Based Attacks

Apply transformation rules to wordlists for more sophisticated attacks:

hashcat -m 0 -a 0 hashes.txt rockyou.txt -r rules/best64.rule

2. Hybrid Attacks

Combine dictionary words with brute-force patterns:

hashcat -m 1000 -a 6 hashes.txt rockyou.txt ?d?d?d
# Appends 3 digits to each word

3. Mask Attacks

Target passwords with known structures:

hashcat -m 1000 -a 3 hashes.txt -1 ?l?u ?1?1?1?1?d?d?d
# -1 ?l?u = custom charset (lower + upper)
# ?1?1?1?1 = first 4 chars are letters
# ?d?d?d = last 3 chars are digits

Optimizing Performance

hashcat -b
# Tests all hash algorithms and shows speeds

hashcat -m 1000 -a 3 hashes.txt ?a?a?a?a?a?a -w 4 -O -u 1
# -w 4 = high workload profile
# -O = optimized kernels
# -u 1 = force usage of specific GPU

Real-World Examples

Cracking WiFi WPA2 Handshakes

hashcat -m 2500 capture.hccapx rockyou.txt
# Requires converted .hccapx file from aircrack-ng

Recovering ZIP Archive Passwords

zip2john archive.zip > zip_hash.txt
hashcat -m 13600 zip_hash.txt rockyou.txt

Breaking Linux Shadow Hashes

unshadow passwd.txt shadow.txt > linux_hashes.txt
hashcat -m 1800 linux_hashes.txt rockyou.txt

Hashcat Potfile

Hashcat saves cracked hashes in ~/.hashcat/hashcat.potfile. To view:

hashcat --show hashes.txt

Conclusion

Hashcat is an incredibly powerful tool for ethical password recovery and penetration testing. By mastering its attack modes, optimization techniques, and real-world applications, security professionals can:

• Test organizational password policies
• Recover lost passwords (with proper authorization)
• Identify weak hashing algorithms in systems
• Enhance overall security posture