The bug identified in the Cranelift x64 backend performs a sign-extend instead of a zero-extend on a value loaded from the stack, when the register allocator reloads a spilled integer value narrower than 64 bits. This interacts poorly with another optimization: the instruction selector elides a 32-to-64-bit zero-extend operator when we know that an instruction producing a 32-bit value actually zeros the upper 32 bits of its destination register. Hence, the x64 compiler relies on these zeroed bits, but the type of the value is still i32, and the spill/reload reconstitutes those bits as the sign extension of the i32’s MSB.

We recently discovered a compiler bug in part of the WebAssembly compiler that we use for Compute@Edge, that could have allowed a WebAssembly module to access memory outside of its sandboxed heap. But because of the people, processes, and tools we have in place, the bug was caught and patched on our infrastructure before it was exploited.

Throwing new security tools at new threats results in scattershot protection and builds technical debt. Organizations need uniform protection for applications and APIs, regardless of where they live.

New Fastly next-gen WAF dashboards surface security telemetry from more than 20 new signals for advanced attack scenarios, such as account takeover, credit card validation, and password reset.

Layer 7 is a primary battleground for web application and API security. Fastly and Okta have partnered together to share threat intelligence, so security and development teams can better protect their systems.

Explore how leaders from both sides of the aisle have built thriving secure DevOps cultures by putting trust in people first.

Teams can now automate their Fastly TLS workflows through Terraform — including issuing certificates, retrieving TLS details, and performing other updates.

Fastly (Signal Sciences) has been recognized as a Customers’ Choice for Web Application Firewalls in the 2021 Gartner Peer Insights “Voice of the Customer” report.

Fastly’s security research team has built and deployed a rule to protect Signal Sciences Next-Gen WAF customers against the recently announced Microsoft Exchange Server vulnerabilities.

The rise of secure DevOps has left many security professionals vying for the attention and support of their engineering counterparts. What can engineering leaders do to bridge the gap? We have four ideas to help you build security into your DevOps culture, workflows, and goals.

A modern CDN can help improve SEO rankings, make it easier to deliver personalized content, and secure your sites and apps — three keys to a startup’s success.

Nearly everything we know about building web applications and APIs has changed in the last few decades. So why hasn't security? We argue it's time for a new approach to web app and API security, one that follows suit with how applications are really built and teams really work.

Fastly and Signal Sciences have joined forces to build the next generation of web app and API security at the edge. Explore what makes our approach different, and how it will empower developers to build more securely than ever before.

DDoS attacks have been growing larger over the past few years. But so has the industry’s response to them. In this post, we take a look at what industry bodies and a modern CDN can do to protect your traffic.

The TLS Support Engineering team provides support for customers managing one to thousands of certificates. After helping so many customers tailor their DNS and TLS configurations, they have five best practices to recommend.

Layer 7 attacks that target applications and issue requests that can swamp origin systems often seek to blend into other network traffic and require a more focused defense than Layer 3 and 4 attacks. Here are five best practices you can implement to help prepare for such attacks.

We believe Signal Sciences’ innovation earned them recognition in the 2019 Gartner Magic Quadrant for WAF, and it’s this kind of innovation that excites us as we merge forces — now that Signal Sciences is part of Fastly.

The largest category of difficult-to-anticipate security design weaknesses come from side-channel attacks. In this post, we take a tour of some of the more foundational and out-there side channel-related exploits that have afflicted the security conscious over the years.

Today, Fastly completed the acquisition of Signal Sciences and took a giant step forward toward our vision of modern, unified web application and API security. We will call on our shared view of empowering developers as we chart a path toward building an incredibly secure, performant platform and unlock all-new possibilities, together.

Following WAF best practices is imperative to keep your business and customers secure. Learn about new regulations and security tips.