A wildcard SSL certificate is a single certificate in which the domain name field contains a wildcard character, often *. Securely transmitting and receiving sensitive data between a website’s core domain and its sub-domains is made possible by a certificate’s ability to authenticate the domain and offer HTTPS encryption across the entire domain tree.
To protect several subdomains of a single domain, wildcard certificates are a good option. You can use a Wildcard SSL to cover your subdomains instead of installing separate certificates.
How do certificates with a “wildcard” work?
A wildcard SSL certificate eliminates the need for several certificates to secure your organization’s web traffic, as it applies to all subdomains. There are two main types of wildcard certificates:
- Domain-validated (DV) certificates can be sent to you quickly after you buy them, but you have to prove that you own the domain.
- Registered businesses can only use organization-validated (OV) certificates, and the certificate will include information about your business. But you must go through a review process before getting approval.
Wildcard SSL certificates have a private key that all subdomains share. During the making of the certificate, when a certificate signing request (CSR) is made, a private key is created. If you use more than one server, you will need to copy the private key to each server when you install the certificate.
Pros of Wildcard SSL
Businesses can be more productive and efficient with wildcard SSL certificates because they make it easy to secure multiple subdomains. For example, wildcards give you the freedom to add subdomains as needed. That saves time on administration and lets you make your IT strategy more flexible.
Buying separate certificates for each subdomain is also more expensive than getting a wildcard SSL. Instead, you can use a single certificate for as many subdomains as you want.
Wildcard certificates are also helpful because they can be used on multiple servers. You can use a single wildcard SSL certificate for multiple subdomains, storing your email on one server and your main public-facing website on another.
Cons of Wildcard SSL
There aren’t many bad things about using a wildcard certificate, but security is the main one. SSL certificates provide a high level of encryption (HTTPS secures websites), but a single certificate means only one point of entry for multiple subdomains. That could make spoofing attacks more likely, where hackers access private information, spread harmful software, or change how things work.
When choosing certificates, server security should be one of the main things to consider. If multiple servers are used, this can put more pressure on the security measures already in place. To install the certificate, you must copy a certificate file to the server and then copy the private key from the primary server to all other servers. Since this requires physically relocating sensitive and vital data, it weakens defenses at different points, such as connections to the server and the procedures for upkeep and authorized access.
The risk of an attack increases the more people are involved, from the person running the domain (the Head of IT) to the registrar (an organization). Since the certificate could be installed on servers outside of the organization, all subdomains that use the wildcard will also be stolen if the private key is stolen.