Let's imagine you're in a situation where a CTO with root access is not the best at recognizing phishing attempts and accidentally leaked a critical root certificate on your build servers. Now, you need to ensure that all deployed applications that relied on this certificate are still secure. How should you tackle this issue?
I run a small to medium business and we're currently redteaming our infrastructure, and while we are implementing better permissions, we need to consider the scenario where someone has managed to gain access to this important certificate. I'm also open to any articles or resources relevant to handling this situation!
3 Answers
The term "root cert" refers to the highest level of a certification authority (CA). If it's compromised, it puts every certificate issued by that root or subordinate CA at risk. The best approach here would be to create a new PKI entirely, secure the new root certificate in a hardware security module (HSM) or physical safe, and reissue certificates to every application that needs one. Disregard the old root CA; it’s not trustworthy anymore.
For edge or cloud server-level certs, usually found in the filesystem and used to MITM your network, do you have a service for key management? How does your infrastructure guard against such leaks?
If you suspect a cert leak, treat it as fully compromised. Start by revoking and rotating the cert. You’ll want to halt any systems using it to prevent spreading trust further. Next, focus on rebuilding trust from a clean state by reissuing new certificates and redeploying verified builds. If you haven't established strong artifact provenance, that will be a significant challenge here.
That makes sense. Which HSMs are popular in modern use? I’m relatively new to this space, and our cloud architecture is still pretty basic.
Revocation of leaked certificates usually involves working with the issuing CA depending on your infrastructure and what tools you use. If you have an intermediary CA cert that can sign a certificate revocation list (CRL), you can revoke it. Just remember, you can't revoke a self-signed cert, so handling those involves removing them from your trust stores after deployment, which can be tricky! Best practice is to avoid self-signed certs for critical uses.
So, if I’m using a cloud-based key management solution, how do I ensure I can spot a severe security issue before it escalates?
Hold on, while the key is sensitive, the root cert itself is public and is installed on numerous devices. It’s important to clarify that! Maybe we’re discussing different types of root certs.