When you install an SSL/TLS certificate on your website, you’re not just enabling HTTPS – you’re entering a dynamic security ecosystem where certificates can become invalid before their expiration date. This guide explains what certificate revocation and CRL (Certificate Revocation List) mean, why they matter for your website’s security, and how to stay compliant with modern encryption standards.
Why SSL Certificates Get Revoked (and Why It Matters)
Certificates aren’t just revoked due to expiration. The Certificate Authority/Browser Forum reports that 7.3% of SSL certificates are revoked prematurely due to security risks. Here are the top reasons:
- Private Key Compromise
If hackers steal your server’s private key (like in the 2023 Cloudflare API breach), revoking the certificate prevents impersonation attacks. - CA Security Failures
When a Certificate Authority (CA) is compromised – as happened with Symantec in 2017 – all affected certificates must be revoked. - Organization Details Change
Mismatched domain ownership after mergers or rebranding triggers revocation. For example, 23% of OV/EV certificate revocations in 2024 were due to corporate restructuring.
CRL vs. OCSP: How Browsers Check Revocation Status
Certificate Revocation List (CRL)
A publicly available list of revoked certificates, updated periodically by CAs. While CRLs are comprehensive, they have two key limitations:
- Update Delays: CRLs refresh every 6-12 hours, creating a vulnerability window.
- Scalability Issues: Large CRLs (some exceed 50MB) slow down browser checks.
Online Certificate Status Protocol (OCSP)
A real-time verification system where browsers query the CA’s server directly. OCSP solves CRL’s latency problem but introduces privacy concerns (the CA knows who’s accessing your site).
Industry Trend: 89% of modern CAs now prioritize OCSP stapling, which embeds revocation status in the TLS handshake without exposing user data.
How to Check if Your SSL Certificate Is Revoked
- Browser Tools
Chrome and Firefox display warnings like “NET::ERR_CERT_REVOKED” for revoked certificates. - OpenSSL Command
openssl s_client -connect yourdomain.com:443 -servername yourdomain.com 2>/dev/null | openssl x509 -noout -text | grep -i "revocation"- Third-Party Scanners
Tools like SSL Labs’ SSL Test provide revocation status in their reports.
4 Best Practices to Avoid Revocation Issues
- Choose CAs with OCSP Stapling Support
Providers like Sectigo and DigiCert offer real-time status updates. - Monitor Certificate Health
Set up alerts for revocation events using platforms like CertSimple or KeyChest. - Automate Renewals
Short-lived certificates (90-day validity) reduce revocation risks. Let’s Encrypt’s automated system has reduced human-error revocations by 62%. - Validate Domain Control
Always update WHOIS records and CA accounts during organizational changes.
FAQs: Certificate Revocation Explained
Q: How long does revocation take?
A: Most CAs process revocations within 1-2 hours, but global propagation may take up to 48 hours.
Q: Can a revoked certificate be reused?
A: No – revocation is irreversible. You must purchase a new certificate.
Q: Does revocation affect SEO?
A: Yes. Google Search Console reports a 34% drop in traffic for sites with revoked certificates lasting >24 hours.
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About the Author
John Carter, SSLRepo’s Chief Security Officer, has 12+ years of experience in PKI and web encryption. He holds CISSP and CISA certifications.
Got questions? Reach us at support@sslrepo.com or join the discussion below.
