In this blog post, I'll describe how to use AFL's experimental persistent mode to blow the doors off of a server without having to make major modifications to the server's codebase. I've used this technique at Fastly to expand testing in some of the servers that we rely on and others that we are experimenting with.

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.

As many of you know, TLS best practices have changed a lot in the past two years. Recently, Fastly has changed how we configure TLS to make it even more secure. This includes migrating our TLS certificates from SHA-1 to SHA-2 and disabling RC4 for all our services.

TLS is especially applicable to news sites. News organizations bear a public responsibility to accurately report the news, and need to take the steps necessary to ensure credibility. The security of online news content is one of the first steps in verifying its veracity while protecting readers.

In this post, I investigate several strategies for maintaining security while improving cacheability. I use Ruby on Rails for the examples, but the techniques apply to nearly any web application framework.

Based on our understanding of the POODLE vulnerability (mainly the fact that there is currently no workaround), and the fact that we have very little traffic running over SSLv3 (around .5% globally), we are disabling SSLv3 for all Fastly SSL customers, effective immediately. This will mainly affect users of Windows XP Pre-service pack 3 combined with IE version 6. If you are in this group, please upgrade to a more recent browser.

Security is one of our top priorities at Fastly. We recognize that having your account compromised could have a profoundly negative impact on your business, leaving you and your customers vulnerable and at risk. So, with enthusiastic feedback from our customers, we've been testing out ways to improve account security features. Today, we're pleased to release two-factor authentication and IP account access restrictions.

Here’s the latest update on the ongoing resolution to critical OpenSSL vulnerability CVE-2014-0160, aka 'Heartbleed,' which was announced on April 7th and affects nearly every Internet service provider and website using SSL to secure customer traffic.