How to Monitor Certificate Transparency Logs for Lookalike Domains

Short summary

Certificate Transparency logs expose newly-issued TLS certificates within minutes, providing early warning of lookalike domains before sites go live. Detection requires combining edit distance, typo permutations, combosquats, TLD variants, and Unicode homoglyph analysis. The piece outlines a practical monitoring pipeline using dnstwist and Unicode confusables (UTS #39), plus production challenges like false positives from your own infrastructure.

• •CT logs expose new certificates within minutes, enabling early detection of lookalike/phishing domains
• •Effective detection requires multi-vector matching: typos, combosquats, TLD swaps, and Unicode homoglyphs
• •Implementation uses dnstwist, Unicode confusables standard, and careful false-positive filtering for legitimate infrastructure

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