CT Monitor Runtime

Real-time Certificate Transparency log monitoring

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About

The Certificate Transparency Real-Time Monitor watches CT logs for newly issued certificates matching your domain patterns, providing immediate visibility into certificate issuance across all Certificate Authorities. It uses the Certificate Transparency protocol to detect unauthorized certificate issuance, track CA behavior, and ensure no certificates are issued without your knowledge.

CT monitoring is a critical security control that complements traditional certificate management. Even if you control your primary certificate issuance process, certificates can be issued by other CAs (with or without authorization). Real-time CT monitoring catches these events immediately, whether they represent legitimate multi-CA strategies, vendor-issued certificates, or unauthorized issuance attempts.

How to Use

1Enter domain patterns to monitor (exact domains or wildcard patterns)
2Configure the monitoring frequency (real-time, hourly, or daily)
3The system continuously queries CT logs for matching certificates
4Receive alerts when new certificates are detected matching your patterns

Use Cases

•Unauthorized Issuance Detection: Immediately detect certificates issued for your domains by CAs you did not authorize, preventing potential phishing or MITM attacks
•CA Monitoring: Track all certificate issuance across your organization including certificates issued by managed CAs, CDN providers, and cloud services
•Phishing Detection: Detect certificates issued for domains similar to yours that could be used for phishing campaigns
•Compliance Evidence: Document CT monitoring as evidence of certificate lifecycle management for PCI DSS and SOC 2 audits
•Vendor Visibility:** Gain visibility into certificates issued by third-party vendors that manage certificates on your behalf

Tips & Best Practices

•Monitor both exact domains and common misspellings (typosquatting patterns)

•Set up real-time alerts for high-value domains and daily summaries for lower-priority domains

•Combine CT monitoring with fingerprint monitoring for complete certificate change detection

•Use wildcard patterns to catch subdomains you may not be directly tracking

Technical Details

●CT Log Sources: Google Argon, Cloudflare Nimbus, DigiCert Yeti, and other participating CT logs

●Search Methods: Exact domain match, wildcard pattern, regex domain matching, and similar-domain detection

●Latency: Real-time mode detects certificates within minutes of CT log submission

●API Integration: Webhook and REST API for automated alerting and response workflows

Frequently Asked Questions

Certificate Transparency (CT) is a system that requires CAs to log all issued certificates in public, append-only logs. This creates a verifiable record of certificate issuance that domain owners can monitor. CT was developed by Google and is now required by all major browsers for SSL certificates.

In real-time mode, certificates are typically detected within 5-15 minutes of issuance. Most CAs submit to CT logs within minutes of certificate issuance. The monitoring system queries logs every 5 minutes in real-time mode, every hour in standard mode, and daily in summary mode.

Yes, you can monitor any domain pattern including domains similar to yours (for phishing detection), competitor domains (for market intelligence), or domains in your industry (for threat awareness). This is useful for detecting certificates issued for typosquatting or brand impersonation.

Related Tools

CT Monitor CT Feed CT Search CT Log Certificate Detail Issuer Identifier