URLCrazy

Overview

URLCrazy is a DNS crawler and domain typosquatting detection tool that identifies similar domain variations of a target domain. It systematically generates domain name variations using typosquatting techniques (character substitution, homoglyph attacks, transposition, omission, and other common mistakes) and checks which variants are registered or actively hosting content. Security professionals use URLCrazy to discover potential phishing domains, domain hijacking, and brand protection vulnerabilities.

Note: Use only for authorized brand protection and security research. Unauthorized domain registration or phishing simulation requires proper legal authorization.

Installation

Linux Installation

# Debian/Ubuntu
sudo apt-get update
sudo apt-get install urlcrazy

# Install dependencies
sudo apt-get install ruby ruby-dev bundler

# Kali Linux (pre-installed)
urlcrazy --version

From Source

# Clone repository
git clone https://github.com/urbanadventurer/urlcrazy.git
cd urlcrazy

# Install dependencies
bundle install
# or
gem install www-mechanize geoip net-dns

# Make executable
chmod +x urlcrazy

# Run directly
./urlcrazy -h

Manual Installation

# Install Ruby first
curl -fsSL https://rvm.io/install.sh | bash
rvm install ruby-2.7

# Install URLCrazy
gem install urlcrazy

# Verify installation
urlcrazy --version

Basic Usage

Command	Description
`urlcrazy domain.com`	Scan domain for typosquatting variations
`urlcrazy -k domain.com`	Perform keyboard-based variations
`urlcrazy -s domain.com`	Check specific variation types
`urlcrazy -o report.html domain.com`	Generate HTML report
`urlcrazy --help`	Display help information

Domain Variation Types

Character Substitution

# Detect homoglyph attacks
urlcrazy domain.com

# Example: domain.com -> dоmain.com (o=о cyrillic)
# Common visual look-alikes detected:
# - l (L) vs I (i)
# - 0 (zero) vs O (letter)
# - 1 (one) vs l (letter)

Typo Detection Methods

# Keyboard typos (adjacent keys)
./urlcrazy domain.com

# Single character typos:
# - Transposition: dmain.com (swap letters)
# - Omission: doman.com (missing letter)
# - Repetition: doomain.com (doubled letter)
# - Substitution: fomain.com (wrong key)

Basic Scanning Operations

Simple Domain Scan

# Scan for typosquatting variations
urlcrazy example.com

# Output shows:
# Domain Name | DNS Status | IP Address | Country | Notes
# example.com | NXDOMAIN | (not registered) | | 
# exmple.com | A | 192.0.2.1 | US | active

Detailed Analysis

# Verbose output with detailed findings
urlcrazy -v example.com

# Shows additional information:
# - Registration status
# - IP geolocation
# - Server response
# - Potential threats

Variation Type Selection

Keyboard Variations

# Focus on keyboard-based typos (adjacent keys)
./urlcrazy -k example.com

# Detects:
# - exakple.com (a next to m)
# - ezample.com (z next to x)
# - examlle.com (l next to k)

Specific Variation Methods

# Try all variation methods
./urlcrazy example.com

# Separate method types:
# 1. Typosquatting (common typos)
# 2. Homoglyphs (visual lookalikes)
# 3. Transposition (letter order)
# 4. Omission (missing letters)
# 5. Substitution (wrong character)
# 6. Pluralization (adding 's')

TLD Variations

# Check different top-level domains
./urlcrazy example.com

# Variations include:
# - example.net (different TLD)
# - example.org (different TLD)
# - example.co (different TLD)

Report Generation

HTML Report Output

# Generate comprehensive HTML report
urlcrazy -o report.html example.com

# Open in browser
firefox report.html
# or
open report.html  # macOS

# Report includes:
# - All domain variations
# - Registration status
# - Active domains with content
# - Geolocation information
# - Threat assessment

CSV/Text Report

# Text-based output
urlcrazy example.com > results.txt

# Pipe to file
urlcrazy example.com | tee scan_results.txt

# Format output for parsing
urlcrazy example.com | grep "A " > active_domains.txt

Advanced Scanning Options

Custom Variation Limits

# Generate limited set of variations
./urlcrazy -l 10 example.com  # Top 10 variations

# Increase variation count
./urlcrazy -l 500 example.com  # Up to 500 variations

DNS Resolution Control

# Check DNS resolution for all variations
./urlcrazy example.com

# Resolution types detected:
# - A record (IPv4)
# - AAAA record (IPv6)
# - MX record (mail)
# - CNAME (alias)

Custom Nameserver

# Use specific nameserver
./urlcrazy -n 8.8.8.8 example.com

# Use Google nameservers
./urlcrazy -n 8.8.8.8 -n 8.8.4.4 example.com

# Alternative nameservers
./urlcrazy -n 1.1.1.1 example.com  # Cloudflare

Threat Detection Workflow

Identify Malicious Domains

# Scan domain and identify threats
urlcrazy -o report.html example.com

# Review active domains
urlcrazy example.com | grep "A\|MX"

# Check for phishing indicators
urlcrazy example.com | grep -E "suspicious|malware"

Verify Registrations

# Check WHOIS information for suspicious registrations
for domain in $(urlcrazy example.com | grep "A " | awk '{print $1}'); do
  echo "Checking: $domain"
  whois $domain | grep -E "Registrant|Created"
done

Monitor Typosquatting Campaigns

#!/bin/bash
# Regular monitoring script

DOMAIN="example.com"
REPORT_DIR="/var/log/urlcrazy"

mkdir -p "$REPORT_DIR"

# Scan periodically
while true; do
  echo "Scanning: $DOMAIN at $(date)"
  urlcrazy -o "$REPORT_DIR/report_$(date +%Y%m%d_%H%M%S).html" "$DOMAIN"
  
  sleep 86400  # Daily
done

Brand Protection Workflow

Corporate Domain Monitoring

# Monitor company domain variations
urlcrazy company.com -o company_report.html

# Check registered variations
urlcrazy company.com | grep "A\|MX" > registered.txt

# Research suspicious registrations
for domain in $(cat registered.txt | awk '{print $1}'); do
  whois $domain | head -20
  echo "---"
done

Phishing Detection

# Detect potential phishing domains
urlcrazy -o phishing_report.html example.com

# Identify newly registered variations
urlcrazy example.com | grep "A " | head -10

# Check content of suspicious domains
for domain in $(urlcrazy example.com | grep "A " | awk '{print $1}'); do
  echo "Content check: $domain"
  curl -s -I $domain | head -5
done

Integration with Security Tools

WHOIS Lookup Integration

#!/bin/bash
# Combine URLCrazy with WHOIS

DOMAIN="$1"
VARIATIONS=$(urlcrazy -l 50 "$DOMAIN")

while read -r variation; do
  if [[ -n "$variation" ]]; then
    WHOIS_INFO=$(whois "$variation" 2>/dev/null)
    
    if [[ ! -z "$WHOIS_INFO" ]]; then
      echo "=== $variation ==="
      echo "$WHOIS_INFO" | grep -E "Registrant|Admin|Created|Expires"
    fi
  fi
done <<< "$VARIATIONS"

DNS Enumeration

# URLCrazy combined with DNS tools
urlcrazy example.com > urlcrazy_results.txt

# Cross-reference with other DNS tools
nmap -p 53 -sV example.com

# Check DNS propagation
for domain in $(cat urlcrazy_results.txt | grep "A " | awk '{print $1}'); do
  nslookup $domain
done

Threat Intelligence Integration

#!/bin/bash
# Check domains against threat intelligence

for domain in $(urlcrazy example.com | grep "A " | awk '{print $1}'); do
  # Check against VirusTotal
  curl -s "https://www.virustotal.com/api/v3/domains/$domain" \
    -H "x-apikey: YOUR_API_KEY" | jq .
    
  # Check reputation
  echo "Checking: $domain"
done

Analysis Techniques

Comparative Domain Analysis

# Scan legitimate domain
urlcrazy -o legitimate.html company.com

# Scan competitor/target
urlcrazy -o competitor.html competitor.com

# Compare results
diff legitimate.html competitor.html | grep -i domain

Homoglyph Detection

# Scan for visual lookalike attacks
urlcrazy company.com | grep -E "0O|l1|rn|vv"

# Manual homoglyph testing
# Common substitutions:
# - Cyrillic о (U+043E) vs Latin o
# - Greek α (U+03B1) vs Latin a
# - Superscript numbers vs regular numbers

Bulk Domain Scanning

#!/bin/bash
# Scan multiple domains

DOMAINS="company.com competitor.org partner.net"

for domain in $DOMAINS; do
  echo "=== Scanning: $domain ==="
  urlcrazy "$domain" | head -20
  urlcrazy -o "report_${domain}.html" "$domain"
done

Performance Optimization

Parallel Scanning

#!/bin/bash
# Scan multiple domains in parallel

DOMAINS=$(cat domains.txt)

for domain in $DOMAINS; do
  (urlcrazy "$domain" -o "report_${domain}.html") &
done

wait  # Wait for all background jobs

Limited Variation Set

# Focus on high-probability variations
./urlcrazy -l 100 example.com

# Limits scanning to most common typos
# Faster execution
# Reduces false positives

Report Analysis

Processing Results

# Extract registered domains
urlcrazy example.com | grep "A " | awk '{print $1}' > registered.txt

# Count active variations
urlcrazy example.com | grep "A " | wc -l

# Identify TLD variations
urlcrazy example.com | grep -v ".com " | head -20

Risk Assessment

# High-risk findings:
# - Newly registered domains similar to target
# - Domains with malware/phishing history
# - Domains hosted on known malicious networks
# - Domains with similar WHOIS registrants

urlcrazy example.com > results.txt
# Manually review high-risk findings

Troubleshooting

DNS Resolution Issues

# Check DNS connectivity
nslookup example.com

# Verify nameserver access
dig @8.8.8.8 example.com

# Try alternative nameserver
./urlcrazy -n 1.1.1.1 example.com

Missing Dependencies

# Install Ruby gems
gem install www-mechanize
gem install geoip
gem install net-dns

# Or use bundler
bundle install

Timeout Issues

# Check network connectivity
ping 8.8.8.8

# Reduce variation count
./urlcrazy -l 50 example.com

# Allow more time for resolution
timeout 300 urlcrazy -l 200 example.com

Best Practices

Authorized Testing

# Ensure authorization before scanning
# Document:
# - Written approval
# - Testing scope
# - Target domain
# - Testing date/time
# - Personnel involved

Regular Monitoring

#!/bin/bash
# Schedule regular typosquatting checks

cat > /etc/cron.d/urlcrazy-monitor <<EOF
# URLCrazy monitoring - daily at 2 AM
0 2 * * * /usr/bin/urlcrazy -o /var/log/urlcrazy/report_\$(date +\%Y\%m\%d).html example.com
EOF

Documentation

# Document findings
echo "Date: $(date)" > scan_log.txt
echo "Domain: example.com" >> scan_log.txt
urlcrazy example.com >> scan_log.txt

# Archive results
tar -czf urlcrazy_scans_$(date +%Y%m%d).tar.gz *.html

Legal Considerations

URLCrazy is legitimate for:

Brand protection and monitoring
Security research and education
Phishing detection
Corporate cybersecurity assessments

Always ensure:

Written authorization from domain owner
Compliance with local laws
Ethical use of findings
Proper documentation
Confidentiality of results

Unauthorized domain registration or spoofing is illegal. Use URLCrazy only for defensive security purposes.