Integrity protection against insiders in microservice-based infrastructures: From threats to a security framework

Building microservices involves continuous modifications at design, deployment, and run times. The DevOps notion together with the “you built it, you run it” paradigm often result in a much larger number of developers with direct access to the production pipeline than in the case of monolithic systems. Reproducible builds and continuous delivery entail practices that further worsen this situation as they grant insiders with indirect accesses (scripted processes) to production machines. Moreover, managing microservices is heavily aided by governance tools (such as Kubernetes) that are configured and controlled by insiders. In this setting, accounting for malicious insiders quickly becomes a major concern. In this paper, we identify representative integrity threats to microservice-based systems in the broader context of a development process by analyzing real-world microservice-based systems. We show that even end-to-end encryption may fall short without adequate integrity protections. From the identified threats, we then derive a set of security requirements for holistic protection. Finally, we propose a framework that serves as a blueprint for insider-resistant integrity protection in microservices.