Gocrack

Gocrack is a distributed password cracking management framework for orchestrating GPU-accelerated hash cracking operations at scale. It provides REST API management, worker coordination, hashcat backend integration, and support for multiple attack methodologies (dictionary, mask, rules, hybrid).

Installation

# Install dependencies (Ubuntu/Debian)
sudo apt install git golang-go nvidia-cuda-toolkit

# Clone and build
git clone https://github.com/fireeye/gocrack
cd gocrack
make build

# Or use Docker
docker pull fireeye/gocrack:latest
docker run -d -p 8080:8080 -v /var/lib/gocrack:/opt/data fireeye/gocrack

Server Setup

Start API Server

# Basic server startup
./bin/gocrack server --listen 0.0.0.0:8080 --db-path /opt/gocrack/db

# With database persistence
./bin/gocrack server \
  --listen 0.0.0.0:8080 \
  --db-path /opt/gocrack/db \
  --max-tasks 100

# Enable debug logging
./bin/gocrack server --listen 0.0.0.0:8080 --db-path /opt/gocrack/db --debug

Start Worker Nodes

# Basic GPU worker
./bin/gocrack worker \
  --api-url http://server:8080 \
  --gpu-type nvidia

# Multi-GPU worker
./bin/gocrack worker \
  --api-url http://server:8080 \
  --gpu-type nvidia \
  --gpu-count 4

# With CPU fallback
./bin/gocrack worker \
  --api-url http://server:8080 \
  --gpu-type nvidia \
  --enable-cpu \
  --cpu-threads 8

Hash Type Support

Hash Type	Hashcat Code	Example
MD5	0	5f4dcc3b5aa765d61d8327deb882cf99
SHA-1	100	e99a18c428cb38d5f260853678922e03
SHA-256	1400	d8e8fca2dc0f896fd7cb4cb0031ba249
SHA-512	1700	Long hash string
bcrypt	3200	$2a$12$hash...
NTLM	1000	Windows hash format
LM	3000	Legacy Windows
MySQL	300	mysqld password format
PostgreSQL	12	PostgreSQL hash
Oracle	3100	Oracle format
WPA/WPA2	22000	WiFi handshake

Task Management

Create Cracking Task

# Basic dictionary attack
curl -X POST http://localhost:8080/api/v1/task \
  -H "Content-Type: application/json" \
  -d '{
    "name": "MD5 Dictionary",
    "hash_type": "md5",
    "hashes_file": "hashes.txt",
    "wordlist": "rockyou.txt",
    "attack_mode": "dictionary"
  }'

# Get task status
curl http://localhost:8080/api/v1/task/{task_id}

# Cancel task
curl -X DELETE http://localhost:8080/api/v1/task/{task_id}

# Get results
curl http://localhost:8080/api/v1/task/{task_id}/results

Prepare Hash File

# Create hash file with newline-separated hashes
cat > hashes.txt << 'EOF'
5f4dcc3b5aa765d61d8327deb882cf99
e99a18c428cb38d5f260853678922e03
d8e8fca2dc0f896fd7cb4cb0031ba249
EOF

# Upload to Gocrack
curl -F "file=@hashes.txt" http://localhost:8080/api/v1/task/upload

Attack Methods

Dictionary Attack

# Basic dictionary attack
curl -X POST http://localhost:8080/api/v1/task \
  -H "Content-Type: application/json" \
  -d '{
    "name": "Dictionary Attack",
    "hash_type": "md5",
    "hashes_file": "hashes.txt",
    "wordlist": "rockyou.txt",
    "attack_mode": "dictionary"
  }'

# Multiple wordlists
curl -X POST http://localhost:8080/api/v1/task \
  -H "Content-Type: application/json" \
  -d '{
    "name": "Multi-Wordlist",
    "hash_type": "md5",
    "hashes_file": "hashes.txt",
    "wordlists": ["rockyou.txt", "passwords.txt", "common.txt"],
    "attack_mode": "dictionary"
  }'

Mask Attack (Pattern-Based)

# Mask attack for pattern cracking
curl -X POST http://localhost:8080/api/v1/task \
  -H "Content-Type: application/json" \
  -d '{
    "name": "Mask Attack",
    "hash_type": "md5",
    "hashes_file": "hashes.txt",
    "attack_mode": "mask",
    "mask": "?u?l?l?d?d?d",
    "increment": true
  }'

# Mask character sets reference
# ?l = lowercase a-z
# ?u = uppercase A-Z
# ?d = digit 0-9
# ?s = special !@#$%^&*()
# ?a = all characters
# ?h = hex 0-9a-f

Combination Attack

# Combine two wordlists
curl -X POST http://localhost:8080/api/v1/task \
  -H "Content-Type: application/json" \
  -d '{
    "name": "Combination Attack",
    "hash_type": "md5",
    "hashes_file": "hashes.txt",
    "attack_mode": "combination",
    "wordlist1": "passwords.txt",
    "wordlist2": "usernames.txt"
  }'

Hybrid Attack (Dictionary + Mask)

# Hybrid attack
curl -X POST http://localhost:8080/api/v1/task \
  -H "Content-Type: application/json" \
  -d '{
    "name": "Hybrid Attack",
    "hash_type": "md5",
    "hashes_file": "hashes.txt",
    "attack_mode": "hybrid",
    "wordlist": "passwords.txt",
    "mask": "?d?d?d?d",
    "dictionary_first": true
  }'

Rule-Based Cracking

Apply Hashcat Rules

# Run with rules
curl -X POST http://localhost:8080/api/v1/task \
  -H "Content-Type: application/json" \
  -d '{
    "name": "Rules Attack",
    "hash_type": "md5",
    "hashes_file": "hashes.txt",
    "wordlist": "passwords.txt",
    "attack_mode": "rules",
    "rules_file": "best64.rule"
  }'

# Common hashcat rule files
# best64.rule - 64 best rules
# d3ad0ne.rule - D3ad0ne set
# dive.rule - Dive rules
# facebook.rule - Facebook patterns

Custom Rules

# Create custom rule file
cat > custom.rule << 'EOF'
# Capitalize first letter
c
# Append numbers
$0 $1 $2 $3
# Append special chars
$! $@ $#
# Duplicate word
d
# Reverse
r
EOF

# Apply custom rules
curl -X POST http://localhost:8080/api/v1/task \
  -H "Content-Type: application/json" \
  -d '{
    "rules_file": "custom.rule",
    "wordlist": "base.txt"
  }'

GPU Optimization

Configure GPU Settings

# Set GPU utilization
./bin/gocrack worker \
  --gpu-type nvidia \
  --gpu-utilization 100 \
  --workload-profile 4

# Check GPU status
nvidia-smi

# Workload profiles
# 1 = Low (laptop)
# 2 = Default
# 3 = High
# 4 = Maximum (needs cooling)

Multi-GPU Coordination

# Specify multiple GPUs
./bin/gocrack worker \
  --api-url http://server:8080 \
  --gpu-type nvidia \
  --gpu-devices 0,1,2,3

# Use specific GPU device
./bin/gocrack worker \
  --api-url http://server:8080 \
  --gpu-device 0

Monitoring Progress

Task Status

# Get task progress
curl http://localhost:8080/api/v1/task/{task_id}/status

# Monitor worker status
curl http://localhost:8080/api/v1/workers

# Get cracking speed
curl http://localhost:8080/api/v1/task/{task_id}/speed

# Estimate completion time
curl http://localhost:8080/api/v1/task/{task_id}/eta

# Export results
curl http://localhost:8080/api/v1/task/{task_id}/results -o cracked.txt

Real-World Workflow

Complete Cracking Job

#!/bin/bash
# Setup and execute password cracking task

SERVER="http://localhost:8080"
HASHES_FILE="captured_hashes.txt"
WORDLIST="rockyou.txt"
HASH_TYPE="md5"

# 1. Create task
TASK_ID=$(curl -s -X POST "$SERVER/api/v1/task" \
  -H "Content-Type: application/json" \
  -d "{
    \"name\": \"Captured Hashes\",
    \"hash_type\": \"$HASH_TYPE\",
    \"hashes_file\": \"$HASHES_FILE\",
    \"wordlist\": \"$WORDLIST\"
  }" | jq -r '.task_id')

echo "[+] Created task: $TASK_ID"

# 2. Monitor progress
while true; do
    STATUS=$(curl -s "$SERVER/api/v1/task/$TASK_ID/status")
    PROGRESS=$(echo "$STATUS" | jq -r '.progress')
    CRACKED=$(echo "$STATUS" | jq -r '.cracked')

    echo "[*] Progress: $PROGRESS% - Cracked: $CRACKED"

    if [ "$PROGRESS" == "100" ]; then
        break
    fi

    sleep 5
done

# 3. Export results
curl -s "$SERVER/api/v1/task/$TASK_ID/results" > cracked_passwords.txt

echo "[+] Cracking complete"
echo "[+] Results saved to cracked_passwords.txt"

Batch Processing Multiple Hash Types

#!/bin/bash
# Process multiple hash files

for hashtype in md5 sha1 sha256; do
    echo "[*] Processing $hashtype hashes..."

    TASK_ID=$(curl -s -X POST http://localhost:8080/api/v1/task \
      -H "Content-Type: application/json" \
      -d "{
        \"name\": \"${hashtype}_crack\",
        \"hash_type\": \"$hashtype\",
        \"hashes_file\": \"${hashtype}_hashes.txt\",
        \"wordlist\": \"rockyou.txt\"
      }" | jq -r '.task_id')

    echo "[+] Created task: $TASK_ID for $hashtype"
done

Best Practices

• Store hashes securely during processing
• Use unique salt values for new passwords
• Implement rate limiting on cracking operations
• Monitor GPU temperature during operation
• Use queue management for resource allocation
• Document all cracking attempts
• Securely delete intermediate files
• Test wordlists before large deployments
• Verify cracked passwords against original hashes

References

• Gocrack GitHub
• Hashcat Documentation
• Hashcat Rules
• John the Ripper

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Last updated: 2026-03-30