Security Misconfigurations in Open Source Kubernetes Manifests: An Empirical Study

Context: Kubernetes has emerged as the de-facto tool for automated container orchestration. Business and government organizations are increasingly adopting Kubernetes for automated software deployments. Kubernetes is being used to provision applications in a wide range of domains, such as time series forecasting, edge computing, and high-performance computing. Due to such a pervasive presence, Kubernetes-related security misconfigurations can cause large-scale security breaches. Thus, a systematic analysis of security misconfigurations in Kubernetes manifests, i.e., configuration files used for Kubernetes, can help practitioners secure their Kubernetes clusters. Objective: The goal of this paper is to help practitioners secure their Kubernetes clusters by identifying security misconfigurations that occur in Kubernetes manifests . Methodology: We conduct an empirical study with 2,039 Kubernetes manifests mined from 92 open-source software repositories to systematically characterize security misconfigurations in Kubernetes manifests. We also construct a static analysis tool called Security Linter for Kubernetes Manifests ( SLI-KUBE ) to quantify the frequency of the identified security misconfigurations. Results: In all, we identify 11 categories of security misconfigurations, such as absent resource limit, absent securityContext , and activation of hostIPC . Specifically, we identify 1,051 security misconfigurations in 2,039 manifests. We also observe the identified security misconfigurations affect entities that perform mesh-related load balancing, as well as provision pods and stateful applications. Furthermore, practitioners agreed to fix 60% of 10 misconfigurations reported by us. Conclusion: Our empirical study shows Kubernetes manifests to include security misconfigurations, which necessitates security-focused code reviews and application of static analysis when Kubernetes manifests are developed.