How can WHOIS data help identify malicious domains?

WHOIS records reveal domain registration details: registrant information, registration date, registrar used, and nameserver configuration. Patterns in this data help identify malicious domains.

Suspicious indicators: very recent registration (brand-new domains), privacy protection hiding registrant (common for legitimate use but also attackers), registrars known for lax abuse handling, and registration shortly after trademark or brand events.

Limitations: privacy services legitimately hide registrant data, sophisticated attackers use clean registration patterns, and GDPR has reduced WHOIS data availability. WHOIS is one investigative tool, not definitive proof.