Here’s a concise incident-style story based on that error message. The Case of the Too-Small Key
Let me clarify: On a Cisco ASA, when acting as an SSL/TLS server (e.g., for VPN), it validates client certificates if client cert auth is enabled. The error “EE key is too small” means a client presented a certificate whose public key size was below the ASA’s configured minimum (default often 1024 or 2048 depending on version/configuration). But in their case, no client cert auth was enabled. cisco asa certificate validation failed. ee key is too small
One Monday morning, users started reporting that their AnyConnect VPN connections were failing. The ASA logs showed: certificate validation failed. ee key is too small The IT team was puzzled—they had just installed a brand-new 2048-bit certificate. Why would the ASA reject it as “too small”? Here’s a concise incident-style story based on that
Upon investigation, the team found that the certificate chain installed on the ASA was incomplete. The ASA had the new server certificate (2048-bit) but still referenced an old, cached intermediate CA certificate that contained a 1024-bit public key. But in their case, no client cert auth was enabled
The ASA was configured for client certificate authentication (accidentally left on from old config) and some remote users were still using old 512-bit or 1024-bit software certificates on their laptops. When those users connected, the ASA attempted to validate their client cert and rejected it because the key size was too small. The confusing part was that the error message appeared in the log at the same time as the new server cert was installed, but it was unrelated.