Background

As we’ve written here before, there’s increasing urgency for organizations—especially those operating in a regulatory environment—to adopt a zero trust network architecture. Just what that means and how to do it may not be immediately clear. When it comes to microservices applications, the National Institute of Standards and Technology (NIST) offers guidance for microservices security in the SP 800-204 series, co-written by Tetrate co-founder Zack Butcher (which we’ve also covered on this blog).

NIST’s reference architecture for microservices security is Kubernetes and the Istio service mesh. In this article, we’ll look at NIST’s recommendations for using a service mesh for authentication and authorization in microservices applications.

At the heart of a zero trust posture is the assumption that an attacker is already in your network. All of these policy recommendations will help prevent potential attackers from pivoting to other resources should they breach your network perimeter. If you use a service mesh as described in the NIST reference platform, all of these capabilities are built into a dedicated infrastructure layer that acts as a security kernel for microservices applications. This means security policy can be applied consistently (and provably) across all your apps—and so your product development teams don’t have to be security experts for your apps to run safely.Service mesh allows fine-grained access control to be layered on top of traditional security measures as part of a defense-in-depth strategy. The mesh sits as a powerful middle layer in the infrastructure: above the physical network and L3/L4 controls you implement, but under the application. This allows more brittle and slower-to-change lower layers to be configured more loosely—allowing more agility up the stack—because controls are accounted for at higher layers.