What is a Wildcard SSL Certificate?

A Wildcard SSL Certificate is a versatile security solution that encrypts and secures multiple subdomains under a single domain. This article will explain what Wildcard SSL Certificates are, how they work, and when to use them.

Quick Overview

• Definition: A certificate that secures a domain and all its first-level subdomains.
• Key Feature: Uses an asterisk (*) to represent all possible subdomains.
• Example: *.example.com covers example.com, blog.example.com, shop.example.com, etc.
• Main Benefits: Cost-effective, easy to manage, flexible for growing websites.

How Wildcard SSL Certificates Work

Wildcard SSL Certificates function similarly to standard SSL/TLS certificates but with extended coverage:

1. Domain Coverage: Secures the main domain and all first-level subdomains.
2. Encryption: Uses the same strong encryption as standard certificates.
3. Authentication: Validates domain ownership and optionally organization details.
4. Implementation: Installed on the server to activate HTTPS for all covered domains.

When to Use a Wildcard SSL Certificate

Consider a Wildcard SSL Certificate when:

• Managing multiple subdomains under a single domain
• Planning to add new subdomains frequently
• Seeking to simplify certificate management
• Looking to reduce costs for securing multiple subdomains

Advantages of Wildcard SSL Certificates

1. Cost-Effective: One certificate covers multiple subdomains, reducing overall expenses.
2. Easy Management: Simplifies the process of securing and maintaining multiple subdomains.
3. Flexibility: Allows for quick addition of new subdomains without purchasing new certificates.
4. Consistent Security: Ensures uniform encryption across all subdomains.

Limitations and Considerations

While Wildcard SSL Certificates offer many benefits, they also have some limitations:

1. Single-Level Coverage: Only secures first-level subdomains (e.g., *.example.com, not *.subdomain.example.com).
2. Potential Security Risks: If compromised, all subdomains are affected.
3. Higher Cost: Initially more expensive than a single-domain certificate.
4. Limited Validation Levels: Typically available only as Domain Validated (DV) or Organization Validated (OV) certificates.

How to Obtain and Install a Wildcard SSL Certificate

1. Choose a Certificate Authority (CA): Select a reputable CA that offers Wildcard SSL Certificates.
2. Generate a Certificate Signing Request (CSR):

• Use your web server’s SSL management tool or OpenSSL
• Include the wildcard domain (e.g., *.example.com) in the Common Name field

• Typically done through email, DNS record, or file upload
• Follow the CA’s specific instructions
  

• Complete the payment process
• The CA will issue your Wildcard SSL Certificate

      5.Install the Certificate:

• Upload the certificate files to your web server
• Configure your server to use the new certificate
• Update your website to use HTTPS

     6. Test the Installation:

• Verify HTTPS is working on your main domain and subdomains
• Use online SSL checkers to ensure proper configuration

Best Practices for Using Wildcard SSL Certificates

1. Secure Storage: Keep the private key highly secure, as it affects all subdomains.
2. Regular Updates: Renew the certificate before expiration to avoid service interruptions.
3. Monitor Usage: Keep track of which subdomains are using the Wildcard certificate.
4. Implement Additional Security Measures: Use firewalls, intrusion detection systems, and regular security audits.
5. Consider Multiple Certificates: For large organizations, using separate certificates for critical subdomains can enhance security.

Alternatives to Wildcard SSL Certificates

1. Multi-Domain (SAN) Certificates: Secure multiple specific domains or subdomains.
2. Individual SSL Certificates: Provide separate certificates for each subdomain.

Can I use wildcard domains in my UCC certificate?

Short answer: You certainly can!

There is certainly no technical reason wildcard domains can’t be incorporated into UCC certificates, and it is often the case that a wildcard domain in a UCC is not only the easiest solution, but the most affordable. In fact, it’s the only solution if you want multiple wildcards in a single SSL certificate.

SSL.com’s Multi-domain UCC can secure multiple sites and multiple subdomains, using fully qualified domain names, wildcard domains and more. To cover unlimited subdomains, just create the wildcard domains (i.e. *.sitename.com) in the common name field or as a SAN (Subject Alternative Name) when you purchase your UCC.

You can even put other wildcards in the SAN fields such as *.sub1.sitename.com, *.sub2.sitename.com, *.another.com, etc. You cannot however, put multiple wildcard levels such as *.*. SSL.com will charge you just $129 per year to add your wildcard SSL to your UCC.

Is SSL.com’s wildcard SSL certificate Organization Validated? (OV)

Yes, SSL.com issues High Assurance (OV) validated Wildcard SSL certificates. Customers purchasing an SSL.com Wildcard certificate will receive a DV Wildcard certificate after going through the standard domain validation process.

Your OV Wildcard certificate will be issued as soon as the additional verification steps are completed and confirmed. We’ll need to verify your company name, address, and phone number in an online business directory.

The business listing may be in an official government database, or with a service similar to Dun & Bradstreet. NOTE: Individuals can also qualify for OV Wildcard certificates by following the guidelines here.

Can I order an EV wildcard SSL certificate?

Unfortunately, wildcard domains cannot use extended validation, per the CA/Browser Forum’s guidelines for Extended Validation (EV) certificates. The same guidelines require that each item contained in an EV certificate be individually vetted, which requires a unique identifier for each item.

If you’re looking for extended validation for multiple subdomains, an EV UCC certificate may be the best option. An EV UCC allows for up to 500 entries (first three are included in the base price).

Conclusion

Wildcard SSL Certificates offer a convenient and cost-effective solution for securing multiple subdomains under a single domain. While they provide flexibility and ease of management, it’s essential to consider their limitations and implement best practices to maintain strong security across your digital infrastructure.