SSL Certificate Management Best Practices

Website security begins with SSL/TLS. But just having a certificate isn’t enough—you need to implement it correctly. This article provides a detailed overview of SSL best practices that web administrators and developers should follow to maintain secure, reliable, and high-performance deployments.

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1. Choosing the Right Certificate Authority (CA)

Choosing the right Certificate Authority (CA) is a crucial first step in securing your website with SSL/TLS. A certificate is only as trustworthy as the CA that issues it, and a poor choice here can expose your site to vulnerabilities or impact your brand’s reputation.

• Selecting a Trusted CA: Ensure that the CA you choose has a proven track record of compliance with industry standards. All publicly trusted CAs undergo audits, but some are more reliable than others. Look for a CA that is regularly audited and has a strong security posture.
• Certificate Authority Authorization (CAA): Implement CAA DNS records to designate which CAs are allowed to issue digital certificates for your domain. This prevents unauthorized CAs from generating certificates, which can safeguard your website from misuse​.
• Minimize the Number of CAs Used: To simplify certificate management and avoid confusion, limit the number of CAs that issue certificates for your organization. This reduces complexity and helps ensure that you trust the root certificates used across your infrastructure​.

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2. Generating and Securing Private Keys

The SSL/TLS protocol relies on public and private key pairs for encryption, where the private key must be kept secure at all times. Mishandling private keys can lead to serious security breaches, such as impersonation attacks.

• Use Strong Private Keys: Use at least a 2048-bit RSA key or a 256-bit ECDSA key. RSA is widely supported, but ECDSA offers better performance with stronger security at shorter key lengths.
• ​Generate Private Keys Securely: Always generate private keys on a trusted, secure machine, preferably one that will deploy the certificate. Avoid letting a CA generate the private key for you, as this increases the risk of exposure.
• Rotate Keys Upon Renewal: Generate new private keys every time a certificate is renewed. Reusing old keys increases the risk of compromise over time​.
• Store Keys Securely: Use encryption and Hardware Security Modules (HSMs) for storing private keys. Limit access to the keys to authorized personnel only.

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3. SSL/TLS Certificate Configuration

Configuring your SSL/TLS certificates properly is essential to avoid browser errors, maintain user trust, and ensure strong encryption.

• Complete Certificate Chains: When deploying SSL/TLS certificates, ensure that all intermediate certificates are properly installed along with your server certificate. Missing intermediate certificates can cause browsers to distrust your website, resulting in warnings or errors.
• Hostname Coverage: Ensure that your certificate covers all domain variations that your website uses, such as both example.com and www.example.com. This prevents invalid certificate errors that confuse users and weaken your site’s credibility​.
• Use SAN Certificates for Multiple Domains: If your website serves multiple domains, use Subject Alternative Name (SAN) certificates. These allow you to protect multiple domains with a single certificate, reducing the management overhead​.

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4. Secure Protocols and Cipher Suites

The SSL/TLS protocols and cipher suites you choose will directly affect the security and performance of your web servers. Using outdated or weak protocols can leave your site vulnerable to attacks, while modern protocols provide both security and performance improvements.

• Use Secure Protocols: Only use modern and secure versions of the TLS protocol, such as TLS 1.2 or TLS 1.3. Older versions like SSL 3.0, TLS 1.0, and TLS 1.1 are considered insecure and should be disabled​.
• Use Strong Cipher Suites: Configure your servers to use strong cipher suites that offer at least 128-bit encryption. Recommended suites include AEAD cipher suites like CHACHA20_POLY1305 and AES-GCM to ensure robust encryption​.
• Enable Forward Secrecy (PFS): Forward Secrecy ensures that even if a private key is compromised, it cannot be used to decrypt past sessions. This can be achieved by using cipher suites that support ECDHE (Elliptic Curve Diffie-Hellman Ephemeral) or DHE (Diffie-Hellman Ephemeral) for key exchange​.

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5. Enforce HTTP Strict Transport Security (HSTS)

HTTP Strict Transport Security (HSTS) is a web security policy mechanism that helps prevent protocol downgrade attacks and forces browsers to connect to your site via HTTPS.

Implementing HSTS ensures that all communication between the client and server happens over a secure HTTPS connection, even if the user attempts to access the site using HTTP. This prevents attackers from forcing the connection to downgrade to an insecure protocol​.

How to Enable HSTS:

1. Ensure your site is fully HTTPS-enabled, including all subdomains.
2. Add the Strict-Transport-Security header to your server configuration with an appropriate max-age (e.g., 31536000 seconds, or one year) and includeSubDomains directive​.
3. Consider adding your site to the HSTS preload list for an extra layer of protection, which ensures that all initial connections to your site are secured by default.

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6. Implement Certificate and Key Management

To maintain a secure SSL/TLS environment, it is essential to manage digital certificates and private keys effectively.

• Regular Certificate Renewal and Key Rotation: Renew SSL certificates regularly within their validity period (at least annually) to avoid the risks associated with an expired certificate and generate a new private key during each renewal to minimize the risk of key compromise. Automated tools like the ACME protocol can simplify this process​.
• Monitor and Automate Certificate Management: Use certificate management platforms or tools to track certificate expiration dates, automate renewals, and deploy certificates consistently across your infrastructure. This helps avoid certificate-related outages, which can damage your site’s reputation.
• Decommissioning Old Certificates: Have a clear process in place for revoking and removing certificates when they are no longer in use, particularly when systems are decommissioned or reconfigured.

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7. Mitigate Common SSL/TLS Vulnerabilities

SSL/TLS vulnerabilities can lead to severe security breaches if not addressed properly. Here are common issues and how to mitigate them:

• Handling Mixed Content: Mixed content occurs when a webpage served over HTTPS includes resources (like images, scripts, or stylesheets) served over HTTP. This can expose the connection to man-in-the-middle (MITM) attacks. To avoid this, ensure that all resources on your website are loaded over HTTPS​.
• Session Resumption: Implement TLS session resumption to improve the performance of secure connections, particularly for clients that disconnect and reconnect frequently. Session resumption reduces the overhead of re-establishing the SSL/TLS handshake, speeding up the connection process.
• OCSP Stapling: Use OCSP stapling to deliver revocation information directly from your web server to clients. This avoids the performance hit caused by browsers needing to contact an OCSP server and helps prevent issues related to certificate revocation checks.

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8. Regular Monitoring and Testing

Continuous monitoring and testing of your SSL/TLS configuration is essential to ensure that your deployment remains secure and efficient.

• Ongoing Security Audits: Regularly scan your SSL/TLS certificates and configurations to detect potential vulnerabilities. Tools like SSL Labs and other security scanners can help identify issues such as weak cipher suites, incomplete certificate chains, or insecure protocol versions​.
• Diagnostic Tools: Use diagnostic tools to verify that your SSL/TLS configuration is functioning correctly. SSL checker tools can ensure that digital certificates are correctly installed, valid, and trusted by all major browsers​.

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Bottom Line

At SSL Dragon, we offer a comprehensive selection of SSL certificates from trusted Certificate Authorities (CAs) like DigiCert, Sectigo, GeoTrust and other, ensuring you find the perfect solution for your needs. As highlighted by HostingAdvice, we’re known for making SSL certificates affordable and accessible to businesses of all sizes. With our intuitive platform and dedicated support, securing your site is as straightforward as it gets.