If you’re in charge of PKI and certificate management at your organization, you know this: self-signed certificates are a double-edged sword. PKI is designed to reconcile trust between two public entities unknown to each other. But it can be used internally, in a vacuum, to essentially label and identify entities so that they can authenticate and gain access to other internal resources (and be a resource themselves).
When a CA signs a cert, they’re basically acting as a notary, officially verifying the legitimacy of each identity, but that’s unnecessary for internal usage upon initial issuance. Consider a factory with thousands of IP-connected devices, many of which requiring communication with other devices to perform their intended task. You don’t need a third party to verify each certificate because you are the third party in this equation; they only need to know they can trust each other.
Therefore, it’s not only easier to self-sign certificates for internal operations, but it makes the most logical sense. However, the lack of third-party verification through a trusted Certificate Authority (CA) makes them risky for public-facing materials. And if a self-signed certificate slips through the sandbox into production, it can lead to browser warnings for users (minor) or failures in the certificate chain (major).
Avoiding these common pitfalls is a matter of diligence and attention to detail. Let’s dive into self-signed certificate management: what to know, what to do, and what to steer clear of to protect your organization.
Problems of self-signed certificates
Understanding the challenges of self-signed certificates and the best practices for certificate management may help your organization avoid some common pitfalls. Some of the most egregious problems include:
Lack of trust.
Self-signed certificates inherently lack the markers of trust recognized by browsers and operating systems. When a browser encounters a self-signed certificate, it will trigger a warning that a user must manually bypass to proceed with the connection. Most users aren’t willing to do this-it undermines confidence in the site’s owner and poses a major barrier for any website or application using self-signed certificates.
Increased potential for man-in-the-middle attacks.
Without the trust of a CA to verify authenticity, attackers can more easily impersonate legitimate services using forged self-signed certificates. Alert fatigue creeps in quickly, desensitizing users to warnings, and a public-facing self-signed certificate is easy to spoof. A user bypassing the warning, assuming the certificate is legitimate, could open the door to an attack without realizing.
Certificate maintenance challenges.
Because they don’t require CA signature, self-signed certificates are often manually issued, renewed, and revoked. This manual management makes it easy to miss important details, leading to a higher likelihood of expired certificates. Expired certificates can cause service outages and security gaps-and in an environment where thousands of certificates need to be maintained, it’s only a matter of time until an errant expired self-signed certificate brings operations to a standstill.
Lack of visibility.
Managing certificates is already complex when dealing with the ever-changing certificate lifecycle; self-signed certificates make it even harder to keep track of every cert in your environment. Without the proper tools, processes, and oversight in place to monitor self-signed certificates, the origin of an unexpected vulnerability or breach might be obscured by poor organization and management.
Failure to meet compliance requirements.
Self-signed certificates often fail to meet the security standards required by modern compliance frameworks such as PCI-DSS, GDPR, and HIPAA. In production environments, the failure to meet these standards could result in non-compliance, legal penalties, and severe damage to an organization’s reputation. It’s true that self-signed certificates can be applied quickly to satisfy sandbox environment testing-but playing fast and loose isn’t really part of security best practices. If self-signed certificates are an essential aspect of your organization’s operations, consider the value of centralized PKI.
Breaking the certificate chain
Let’s face it-we don’t trust self-signed certificates for the same reason the U.S. Treasury puts watermarks on twenty-dollar bills. The certificate chain of trust, leading back to a trusted root CA, is critical to secure communications between users, applications, and devices. As the FDIC insures the value of twenty dollars, so do trusted CAs validate the authenticity of certificates. Self-signed certificates can disrupt this delicate chain, exposing organizations to security risks and causing accessibility issues for websites and applications.
When a web browser tries to verify the authenticity of a certificate, it traces the chain of signatures back to the trusted root CA. Without a higher authority to verify against, the validation process fails, resulting in the browser trust errors. Accompanied by firm language like “Your connection is not private” or “This site’s certificate isn’t trusted,” these warnings can be enough to drive users away from a website or application, damaging user experience and service credibility.
One self-signed certificate slipping through the cracks might seem like an easy problem to fix, but the stakes include availability, compliance, and your reputation. Implementing a secure, centralized PKI solution and limiting the number of self-signed certificates in your organization are crucial first steps to maintaining your trusted certificate chain.
Best practices for handling self-signed certificates
Your devs might not be ready to let go of self-signed certificates entirely, but you can adopt best practices across the enterprise for secure, reliable certificate management:
- Use CA-signed certificates wherever possible. Some enterprise-level CA solutions will allow you to distribute CA-signed certificates at will, with the same speed and efficiency as a self-signed certificate would. Wherever possible, use certificates that are bound to a trusted CA, and only use CA-signed certificates for public-facing websites or applications.
- Implement automated certificate management. Manual processes are a fertile field for human error. Automate the certificate management process to minimize errors made in manual issuance, renewal, expiration, and revocation. Plus, automation frees up time for more strategic, proactive tasks.
- Use intermediate certificates to bridge the chain of trust. Intermediate certificates are like branches of root certificates, providing an extra layer of security by distributing trust across the certificate hierarchy. While it’s common to have just one intermediate certificate in a certificate chain, larger organizations or more complex infrastructures may need multiple intermediates to enhance security.
Centralizing all PKI management, even self-signed certificates, can minimize the risk of these useful certificates causing problems later. Establish workflows to audit and monitor self-signed certificates and use automated certificate management to save time in the process.
Call in the experts.
Self-signed certificates may be useful in testing and sandbox environments, but they pose significant security risks when they make it into production environments. Use CA-signed certificates, intermediate certificates, and automated certificate management to maintain secure, trustworthy digital communication within and without your organization. For expert advice on certificate management and automated PKI solutions, follow Keyfactor to stay up to date with the latest in secure certificate practices. Keyfactor’s trusted solutions can help you simplify your certificate management process and protect your organization from vulnerabilities.
