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Generate domain permutations with dnstwist and check DNS resolution to detect typosquatting, homograph phishing, and brand impersonation domains registered against your organization. Use when asked to monitor for lookalike domains, investigate a phishing domain, or assess brand-impersonation risk.
npx skill4agent add mukul975/anthropic-cybersecurity-skills analyzing-typosquatting-domains-with-dnstwistdnstwistpip install dnstwist[full]import subprocess
import json
import csv
from datetime import datetime
def run_dnstwist_scan(domain, output_file=None):
"""Run dnstwist scan against a target domain."""
cmd = [
"dnstwist",
"--registered", # Only show registered domains
"--format", "json", # Output in JSON
"--nameservers", "8.8.8.8,1.1.1.1",
"--threads", "50",
"--mxcheck", # Check MX records
"--ssdeep", # Fuzzy hash comparison
"--geoip", # GeoIP lookup
domain,
]
print(f"[*] Scanning permutations for: {domain}")
result = subprocess.run(cmd, capture_output=True, text=True, timeout=600)
if result.returncode == 0:
results = json.loads(result.stdout)
registered = [r for r in results if r.get("dns_a") or r.get("dns_aaaa")]
print(f"[+] Found {len(registered)} registered lookalike domains")
if output_file:
with open(output_file, "w") as f:
json.dump(registered, f, indent=2)
print(f"[+] Results saved to {output_file}")
return registered
else:
print(f"[-] dnstwist error: {result.stderr}")
return []
results = run_dnstwist_scan("example.com", "typosquat_results.json")def analyze_results(results, legitimate_ips=None):
"""Analyze dnstwist results and prioritize threats."""
legitimate_ips = legitimate_ips or set()
high_risk = []
medium_risk = []
low_risk = []
for entry in results:
domain = entry.get("domain", "")
fuzzer = entry.get("fuzzer", "")
dns_a = entry.get("dns_a", [])
dns_mx = entry.get("dns_mx", [])
ssdeep_score = entry.get("ssdeep_score", 0)
risk_score = 0
risk_factors = []
# High similarity to legitimate site
if ssdeep_score and ssdeep_score > 50:
risk_score += 40
risk_factors.append(f"high web similarity ({ssdeep_score}%)")
# Has MX records (can receive email / phishing)
if dns_mx:
risk_score += 20
risk_factors.append("has MX records (email capable)")
# Recently registered (if whois data available)
whois_created = entry.get("whois_created", "")
if whois_created:
try:
created = datetime.fromisoformat(whois_created.replace("Z", "+00:00"))
age_days = (datetime.now(created.tzinfo) - created).days
if age_days < 30:
risk_score += 30
risk_factors.append(f"recently registered ({age_days} days)")
elif age_days < 90:
risk_score += 15
risk_factors.append(f"registered {age_days} days ago")
except (ValueError, TypeError):
pass
# Homoglyph attacks are highest risk
if fuzzer == "homoglyph":
risk_score += 25
risk_factors.append("homoglyph (visually identical)")
elif fuzzer in ("addition", "replacement", "transposition"):
risk_score += 10
risk_factors.append(f"permutation type: {fuzzer}")
# Not pointing to legitimate infrastructure
if dns_a and not set(dns_a).intersection(legitimate_ips):
risk_score += 10
risk_factors.append("different IP from legitimate")
entry["risk_score"] = risk_score
entry["risk_factors"] = risk_factors
if risk_score >= 50:
high_risk.append(entry)
elif risk_score >= 25:
medium_risk.append(entry)
else:
low_risk.append(entry)
high_risk.sort(key=lambda x: x["risk_score"], reverse=True)
medium_risk.sort(key=lambda x: x["risk_score"], reverse=True)
print(f"\n=== Typosquatting Analysis ===")
print(f"High Risk: {len(high_risk)}")
print(f"Medium Risk: {len(medium_risk)}")
print(f"Low Risk: {len(low_risk)}")
if high_risk:
print(f"\n--- High Risk Domains ---")
for entry in high_risk[:10]:
print(f" {entry['domain']} (score: {entry['risk_score']})")
for factor in entry['risk_factors']:
print(f" - {factor}")
return {"high": high_risk, "medium": medium_risk, "low": low_risk}
analysis = analyze_results(results, legitimate_ips={"93.184.216.34"})import time
import hashlib
class TyposquatMonitor:
def __init__(self, domains, known_domains_file="known_typosquats.json"):
self.domains = domains
self.known_file = known_domains_file
self.known_domains = self._load_known()
def _load_known(self):
try:
with open(self.known_file, "r") as f:
return json.load(f)
except FileNotFoundError:
return {}
def _save_known(self):
with open(self.known_file, "w") as f:
json.dump(self.known_domains, f, indent=2)
def scan_all_domains(self):
"""Scan all monitored domains for new typosquats."""
new_findings = []
for domain in self.domains:
results = run_dnstwist_scan(domain)
for entry in results:
domain_key = entry.get("domain", "")
if domain_key not in self.known_domains:
entry["first_seen"] = datetime.now().isoformat()
entry["monitored_domain"] = domain
self.known_domains[domain_key] = entry
new_findings.append(entry)
print(f" [NEW] {domain_key} ({entry.get('fuzzer', '')})")
self._save_known()
print(f"\n[+] New typosquatting domains found: {len(new_findings)}")
return new_findings
def generate_alert(self, findings):
"""Generate alert for new high-risk typosquatting domains."""
analysis = analyze_results(findings)
alerts = []
for entry in analysis["high"]:
alerts.append({
"severity": "HIGH",
"domain": entry["domain"],
"target": entry.get("monitored_domain", ""),
"risk_score": entry["risk_score"],
"risk_factors": entry["risk_factors"],
"dns_a": entry.get("dns_a", []),
"dns_mx": entry.get("dns_mx", []),
"timestamp": datetime.now().isoformat(),
})
return alerts
monitor = TyposquatMonitor(["mycompany.com", "mycompany.org"])
new_findings = monitor.scan_all_domains()
alerts = monitor.generate_alert(new_findings)def export_blocklist(analysis, output_file="blocklist.txt"):
"""Export high-risk domains as blocklist for firewall/proxy."""
domains = []
for entry in analysis["high"] + analysis["medium"]:
domain = entry.get("domain", "")
if domain:
domains.append(domain)
with open(output_file, "w") as f:
f.write(f"# Typosquatting blocklist generated {datetime.now().isoformat()}\n")
for d in sorted(set(domains)):
f.write(f"{d}\n")
print(f"[+] Blocklist saved: {len(domains)} domains -> {output_file}")
return domains
def generate_takedown_report(high_risk_domains):
"""Generate takedown request report."""
report = f"""# Domain Takedown Request
Generated: {datetime.now().isoformat()}
## Summary
{len(high_risk_domains)} domains identified as potential typosquatting/phishing.
## Domains Requiring Takedown
"""
for entry in high_risk_domains:
report += f"""
### {entry['domain']}
- **Permutation Type**: {entry.get('fuzzer', 'unknown')}
- **IP Address**: {', '.join(entry.get('dns_a', ['N/A']))}
- **MX Records**: {', '.join(entry.get('dns_mx', ['N/A']))}
- **Risk Score**: {entry.get('risk_score', 0)}
- **Risk Factors**: {'; '.join(entry.get('risk_factors', []))}
- **Web Similarity**: {entry.get('ssdeep_score', 'N/A')}%
"""
with open("takedown_report.md", "w") as f:
f.write(report)
print("[+] Takedown report generated: takedown_report.md")
export_blocklist(analysis)
generate_takedown_report(analysis["high"])