Secure Socket Layer (SSL) certificates are an important facet of Internet Security. SSL, otherwise known as TLS certificates, are simply digital certificates issued by trusted public or private Certificate Authorities (CA) to authenticate a domain addressing a public website. There are many types of SSL, including what is known as a wildcard certificate. Well, organizations will often have public domains and subdomains that need SSL certificates.
This is where a wildcard SSL certificate can help secure the main and the subdomains. Yes, you only acquire a single public key certificate and roll it on multiple subdomains. While this looks like an obvious way to save resources, it is not without flaws. There are several risks associated with wildcard certificates, which explains why you need to understand them before pulling a trigger meticulously. Let’s expound more on this:
Centralized Point of Failure
Remember, with wildcard certificates; you are essentially leveraging one key for all the servers and domains using this same certificate. Now, if this private key is compromised in any way, the whole mess is passed to other servers and subdomains that use this same key (those listed in your wildcard certificate). Although you can secure unlimited subdomains, all the other subdomains are affected if the key is compromised.
With ordinary SSL certificates, every server has an individual certificate. So, if the private key of the SSL certificate of one server is compromised, it is only that particular server that is affected. The problem is not channelled to other servers/domains; they have individual certificates.
Private Key Management
While wildcard certificates offer flexibility by letting organizations add as many subdomains as they like, management of the respective private key is a massive problem. The crux of the matter is how an organization at the same time can disperse the key across several servers and teams while effectively and securely managing it.
Without in-depth thinking, it is obvious that this setup creates a dangerous platform for intruders to sneak into domains. It is easier for attackers to steal private keys; for example, it can happen if someone mishandles the key. Another thing to remember is that plenty of users aren’t sensitized to cyberattacks and can be serious loopholes in cybersecurity. Once they access the private key, they can impersonate the domain or use the compromised server to host malicious sites for carrying out cyberattacks.
Think about a situation where the wildcard certificate is revoked or has expired. It means all the servers using the wildcard certificate key are disrupted. What if you are running important business transactions? It could prove costly because all the respective sub-domains are interrupted.
Updating a revoked or a nearly expired wildcard certificate is not that easy. It can prove more daunting, especially if the geographical distribution of the servers is large and when the level of visibility on your infrastructure is not good.
When doing an update, the private key should be updated for all the servers that use the wildcard certificate. This process should also be done simultaneously so that the smooth flow of data is not disrupted.
So, if you are using a wildcard certificate, you better renew it on time to avert significant outages that could prove costly to your business. Fortunately, there are several ways to help you keep track of your important certificate dates. You can even leverage certificate lifecycle automation tools like Keyfactor to keep an accurate and updated inventory of your certificates.
There is no Extended Validation Option
Because wildcard certificates allow an unlimited number of sub-domains, it is impossible to meet the CA/B Forum rules requiring every certificate authority to undergo a rigorous validation process. Therefore, wildcard certificates are available with only the domain validation (DV) and the Organization Validation (OV) options.
While this may not sound much of a risk, most companies prefer the prestigious EV because they underwent rigorous testing. Even without the prestige tag, it still means a lot in terms of security that a rigorous validation process is conducted. Companies that opt for EV cannot have wildcard SSL work on their side.
Complicated for Multi-Level
It is no secret that wildcards secure unlimited subdomains. However, there are limitations within the levels of sub-domains you can secure as well. Suppose an organization, for example, has multiple domains or simply domains of diverse top-level domains. In that case, they will need to buy different wildcards for these different domains or purchase a multi-domain wildcard SSL certificate.
A good example is when you have to-level domains like .in, .org, .net, and .au, among others. Again, if you have second-level sub-domains, be sure a wildcard certificate that belongs to the first level subdomain won’t extend to the second-level subdomain.
This means you also have to buy a separate SSL certificate for the different levels. It can prove a bit more complex to manage with different levels and domains than the traditional easy to manage wildcards certificate on a single-level subdomain. So, if you don’t properly track things like SSL expiry dates, then the inevitable downtime can prove painful, especially if all the certificates expire at the same time.
The Bottom Line
Well, Wildcard certificates offer several advantages to organizations. Mention flexibility, fast implementation, cost-saving, ability to secure unlimited subdomains, and ease of certificate management among others. However, wildcard certificates cannot just be deployed without an in-depth analysis of the pros vs cons associated with the same.
Organizations need to understand the risks before committing to wildcard certificates to avoid dragging themselves into a furnace. The major risks surrounding wildcard certificates are more of security and cannot be avoided. It is a debate of whether you need flexibility and less cost or a more fortified network.
We hope our quick guide has expounded on these risks and after reading it. It is time to now make an informed decision as to whether you go the wildcard certificates way or the ordinary SSL/TLS authentication.