Daniel McCarney

Fastly is not vulnerable to Logjam — we only offer the more secure Elliptic Curve variant of the Diffie-Hellman key exchange (ECDHE), and the RSA key exchange mechanism for clients that don’t support ECDHE. Since Fastly does not offer any export grade ciphersuite options — and we do not offer the Diffie-Hellman key exchange mechanism — our services are not affected.

If you follow the security news cycle, you may have seen recent discussions about Google detecting a Certificate Authority (CA) in China improperly issuing certificates capable of transparently (that is, without warning) imitating Google TLS-protected websites. As part of the subsequent investigation, Google removed the implicated CA from the list of trusted CAs and indicated that in order for the CA to be considered for re-inclusion, they would have to implement a system known as Certificate Transparency (CT). Below, I’ll outline the basics of CT and how it relates to this and other CA-related incidents in recent history.

Rotation, expiration, and revocation of secrets are all important concerns that require careful and difficult up-front design. Transport Layer Security (TLS), the protocol underlying secure web traffic (HTTPS), is one of the cryptographic systems with the largest deployment and day-to-day use, and serves as a good case study for all of the proceeding concerns. In this post, I’ll discuss how revocation is addressed in TLS, and how it relates to both performance and security.

Fastly has evaluated each of these vulnerabilities and found that only one moderate-severity bug affects our configuration. We are currently testing the patch and coordinating a global release of the updated software across Fastly’s network. We anticipate no customer impact or configuration changes.

We’re huge fans of Transport Layer Security (TLS) at Fastly. Here’s a behind-the-scenes look at how we do encryption at the edge, which can also serve as overall best practices for handling server-side TLS.