Evaluation of security threats in microservice architectures

Abstract: The microservice architecture is a popular architectural pattern in the industry to implement large systems as they can reduce the code bases of each service and increase the maintainability for each of the individual services by dividing the application into smaller components based on business logic. The services can be implemented in different programming languages and communicates over a network. As a consequence, it might lead to a greater attack surface for an adversary of the system. In order to ease the implementation of microservice architectures, a set of design patterns exists. Two patterns addressing the security of the architecture are the API Gateway pattern and the sidecar pattern. More research is needed in order to identify the security threats microservice architecture encounters and how the design pattern handles those. This master thesis uses threat modeling with attack graphs along with attack simulations in order to investigate the threats in microservice architectures and how they compare between the design patterns. To construct the attack graphs and perform the attack simulations SecuriCAD along with CoreLang was used on a microservice architecture with each of the design patterns. The report concludes that the sidecar pattern is faced with less risk than the API Gateway pattern overall and presents a set of suggestions regarding how the security can be improved in microservice architectures.