SSL (Secure Socket Layer) certificates are crucial for establishing secure and encrypted connections between web servers and clients. However, sometimes SSL certificate validation errors can occur, potentially indicating security vulnerabilities. This knowledge base provides detailed information on how to identify and resolve SSL certificate validation errors in WHM cPanel.

1. Understanding SSL Certificate Validation Errors:

   • SSL certificate validation errors occur when a client encounters issues while verifying the authenticity of an SSL certificate.

2. Accessing WHM for SSL Certificate Management:

   • Log in to WHM using your administrator credentials.

3. Navigating to SSL/TLS Management:

   • Locate and select 'SSL/TLS' from the WHM menu.

4. Viewing Installed SSL Certificates:

   • Click on 'Manage SSL Hosts' to view a list of installed SSL certificates for various domains.

5. Identifying Certificate Validation Errors:

   • Review SSL certificates to identify any validation errors reported by clients.

6. Checking Certificate Chain:

   • Ensure that the SSL certificate chain is properly configured and that all intermediate certificates are correctly installed.

7. Verifying Domain and Common Name (CN) Match:

   • Confirm that the domain name in the SSL certificate matches the domain being accessed.

8. Checking Certificate Expiry Dates:

   • Review the expiry dates of SSL certificates to ensure they are still valid.

9. Examining Certificate Authority (CA) Root Trust:

   • Confirm that the CA root certificate is trusted by clients.

10. Resolving Certificate Chain Issues:

    • If there are issues with the certificate chain, reinstall or reconfigure the SSL certificate with the correct intermediates.

11. Reissuing SSL Certificates:

    • If necessary, reissue SSL certificates to address validation errors, following proper procedures.

12. Ensuring Private Key Match:

    • Verify that the private key used with the SSL certificate matches the public key in the certificate.

13. Checking for Mixed Content Issues:

    • Confirm that all resources (images, scripts, etc.) on the website are served securely via HTTPS to prevent validation errors.

14. Implementing HTTP Strict Transport Security (HSTS):

    • Enable HSTS to ensure that clients always connect securely via HTTPS.

15. Handling Certificate Revocation:

    • If a certificate is compromised or no longer valid, revoke it and replace it with a new one.

16. Resolving Domain Mismatch Errors:

    • If the domain name in the SSL certificate does not match the accessed domain, reissue or obtain a certificate for the correct domain.

17. Handling Expired Certificates:

    • Replace expired certificates promptly to avoid security warnings and potential loss of trust.

18. Configuring Server Name Indication (SNI):

    • Enable SNI support to allow multiple SSL certificates on the same IP address.

19. Educating Users on Certificate Validation:

    • Provide guidelines to users on how to troubleshoot SSL certificate validation errors on their own devices.

20. Documenting SSL Certificate Management:

    • Keep detailed records of SSL certificates, their expiration dates, and any actions taken to resolve validation errors.

21. Conducting Regular SSL Audits:

    • Periodically review SSL certificates to ensure they are properly configured and free of validation errors.

Conclusion:

Resolving SSL certificate validation errors in WHM cPanel is essential for maintaining secure and trusted connections between servers and clients. By following the steps outlined in this knowledge base, you can efficiently identify and address SSL certificate validation issues, ensuring that SSL connections are established securely and without errors. This enhances the overall security and trustworthiness of your server.