Implementation and Analysis of Authentication and Authorization Methods in a Microservice Architecture : A Comparison Between Microservice Security Design Patterns for Authentication and Authorization Flows

Abstract: Microservices have emerged as an attractive alternative to more classical monolithic software application architectures. Microservices provides many benefits that help with code base comprehension, deployability, testability, and scalability. As the Information technology (IT) industry has grown ever larger, it makes sense for the technology giants to adopt the microservice architecture to make use of these benefits. However, with new software solutions come new security vulnerabilities, especially when the technology is new and vulnerabilities are yet to be fully mapped out. Authentication and authorization are the cornerstone of any application that has a multitude of users. However, due to the lack of studies of microservices, stemming from their relatively young age, there are no standardized design patterns for how authentication and authorization are best implemented in a microservice. This thesis investigates an existing microservice in order to secure it by applying what is known as a security design pattern for authentication and authorization. Different security patterns were tested and compared on performance. The differing levels of security provided by these approaches assisted in identifying an acceptable security versus performance trade-off. Ultimately, the goal was to give the patterns greater validity as accepted security patterns within the area of microservice security. Another goal was to find such a security pattern suitable for the given microservice used in this project. The results showed a correlation between increased security and longer response times. For the general case a security pattern which provided internal authentication and authorization but with some trust between services was suggested. If horizontal scaling was used the results showed that normal services proved to be the best target. Further, it was also revealed that for lower user counts the performance penalties were close to equal between the tested patterns. This meant that for the specific case where microservices sees lower amounts of traffic the recommended pattern was the one that implemented the maximum amount access control checks. In the case for the environment where the research were performed low amounts of traffic was seen and the recommended security pattern was therefore one that secured all services of the microservices.