The Ultimate Guide to AWS SSL Certificate Renewal and Best Practices

Securing your web applications is not just a best practice—it’s essential. One of the most critical aspects of this security is ensuring that your SSL/TLS certificates remain valid and trusted. When you’re running applications on Amazon Web Services (AWS), managing and renewing these certificates through AWS Certificate Manager (ACM) becomes both convenient and crucial. This guide covers everything you need to know about AWS SSL certificate renewal, including best practices to follow to maintain secure operations.

Understanding AWS SSL Certificates

AWS Certificate Manager allows you to easily provision, manage, and deploy SSL/TLS certificates for use with AWS services. These certificates are used to secure connections between clients and your AWS-hosted applications, ensuring encrypted data transmission.

ACM supports both public and private certificates, and it automatically handles renewals for certificates issued by Amazon if they are associated with specific AWS load balancers, CloudFront distributions, or API Gateway custom domains.

Types of SSL Certificates in AWS

Understanding certificate types helps in applying the correct renewal process:

• Public ACM Certificates: Issued by Amazon, free of charge, only for use with AWS services.
• Imported Certificates: Certificates you bring in from external Certificate Authorities (CAs).
• Private ACM Certificates: Generated using AWS Private CA, suited for internal services.

Automatic vs. Manual Renewal

One of the advantages of using certificates issued by ACM is that AWS handles the renewal process automatically, provided the certificate is actively associated with a supported service. However, if it is an imported certificate or there is a manual step required (e.g., domain validation), manual intervention becomes necessary.

Automatic Renewal

ACM initiates the renewal process 60 days before the certificate expires. To ensure that automatic renewal completes successfully:

• Ensure that DNS validation records are in place if you used DNS validation for the certificate.
• Keep the certificate associated with at least one supported AWS resource.

If these conditions are met, ACM will renew and deploy the certificate without requiring your involvement. This automation makes ongoing management significantly easier and reduces the risk of application downtime due to expired certs.

Manual Renewal for Imported Certificates

If you’ve imported an SSL certificate into ACM, Amazon won’t manage or renew it. You’ll need to manually repeat the following steps:

1. Request or purchase a renewed certificate from your external CA.
2. Convert the certificate to a compatible PEM format if necessary.
3. Replace the expiring certificate in ACM using the AWS Console, CLI, or SDK.
4. Update any associated resources to use the renewed certificate.

Assigning personnel or implementing internal systems to monitor expiration dates on imported certificates is a recommended best practice.

Best Practices for AWS SSL Certificate Renewal

Neglecting proper management of SSL certificates can lead to application outages, loss of trust, and compliance issues. Here are some best practices to avoid these pitfalls:

1. Monitor Expiration Dates

While ACM auto-renews certificates, imported ones do not enjoy the same benefit. Implement monitoring through AWS Config Rules, CloudWatch Events, or external setups that alert you 60–90 days before expiration.

2. Use DNS Validation Where Possible

Amazon ACM supports two kinds of domain validation: Email and DNS. DNS validation is preferred because it allows silent renewal without manual intervention. Once you set up the required CNAME records, ACM does the rest.

3. Regularly Review Certificate Usage

Unused or orphaned certificates can clutter your AWS environment and even pose security risks if not managed. Use AWS Trusted Advisor or custom scripts to detect and remove obsolete certificates.

4. Automate with Infrastructure as Code (IaC)

If you are deploying certificates across multiple environments frequently, use tools like AWS CloudFormation or Terraform to manage issuance, updates, and associating certificates with resources such as Load Balancers or API Gateway.

5. Ensure Proper IAM Permissions

Set strict permissions using AWS IAM policies to restrict who can issue, import, delete, or replace certificates. Employ the principle of least privilege to reduce security risk.

Renewal Process Walkthrough

For ACM-Managed Certificates

If your certificate fulfills all auto-renewal criteria, you don’t need to act unless the process fails. To check renewal status:

1. Open AWS Certificate Manager.
2. Select your certificate.
3. Check the “Renewal Status” tab in the Overview panel.

If it indicates a problem (e.g., domain validation failure), take appropriate steps such as re-adding validation records or reinitiating validation.

For Imported Certificates

Here’s how you manually renew an imported certificate:

1. Proceed to your external CA and renew your certificate.
2. Download certificate and private key files in .PEM format.
3. Log into the AWS Console and navigate to Certificate Manager.
4. Choose “Import a certificate” and upload the renewed files.
5. Replace old certificate associations with the new one on your AWS resources.

Be careful during scheduling: avoid doing this during high-traffic hours. A rollout window with rollback plans ensures minimal interruption.

Validating Certificate Updates

After a renewal (automatic or manual), validate that your resources correctly use the newly issued certificate. You can verify using:

• Web Browsers: Navigate to your application and inspect the certificate validity dates.
• OpenSSL: Run openssl s_client -connect yourdomain.com:443 and inspect the certificate details.
• CloudWatch Logs: Monitor request errors post-renewal for potential SSL handshake issues.

Troubleshooting Common Issues

1. Renewal Fails Due to Domain Validation

Make sure the DNS validation records are not accidentally deleted or modified. Keep your DNS zones intact at all times, especially around ACM validation entries.

2. Association with Service Removed

If your certificate is disassociated before renewal (e.g., removed from a load balancer), ACM does not renew it. Restore the association or manually request a new certificate.

3. Certificate Not Updating on Resources

Check that resources like Application Load Balancers or CloudFront distributions are referencing the updated certificate ARN. Restart or redeploy resources if updates are not reflected.

Planning for Long-Term Security and Compliance

SSL/TLS certificates contribute significantly to compliance with security frameworks such as SOC 2, PCI-DSS, and ISO 27001. Regular audits of certificate use and renewal practices are vital for meeting audit requirements and protecting user data.

Also consider enabling AWS CloudTrail logs to track all actions related to certificates and proactively detect unauthorized changes or threats.

Conclusion

Properly managing AWS SSL certificate renewals ensures that your application maintains strong encryption, trustworthiness, and uptime. By automating what you can and closely monitoring what you can’t, you greatly reduce the risk of expired certificates disrupting operations. Combine automated AWS features with solid operational practices, and you’ll have an SSL strategy that scales securely with your business.

Remember, SSL isn’t just a technical implementation—it’s a critical layer of digital trust. Ensure your practices reflect its significance.