SecIngress: An API gateway framework to secure cloud applications based on N-variant system

Based on the diversified technology and the cross-validation mechanism, the N-variant system provides a secure service architecture for cloud providers to protect the cloud applications from attacks by executing multiple variants of a single software in parallel and then checking their behaviors' consistency. However, it is complex to upgrade current Software as a Service (SaaS) applications to adapt N-variant system architecture. Challenges arise from the inability of tenants to adjust the application architecture in the cloud environment, and the difficulty for cloud service providers to implement N-variant systems using existing API gateways. This paper proposes SecIngress, an API gateway framework, to overcome the challenge that it is hard in the cloud environment to upgrade the applications based on N-variants system. We design a two-stage timeout processing method to lessen the service latency and an Analytic Hierarchy Process Voting under the Metadata mechanism (AHPVM) to enhance voting accuracy. We implement a prototype in a testbed environment and analyze the security and performance metrics before and after deploying the prototype to show the effectiveness of SecIngress. The results reveal that SecIngress enhances the reliability of cloud applications with acceptable performance degradation.