KubeGuard: A Systematic Permission-Oriented Risk Detection Approach for Kubernetes Applications

Kubernetes is a popular containerized application orchestration platform that is widely adopted for the development of large-scale service-oriented systems. Such a system often involves the integration of third-party applications, which may introduce security risks, such as excessive permission configurations and privilege escalations, resulting in the leakage of sensitive resources and unauthorized operations. Existing risk detection techniques mainly examine the permission configurations with some predefined rules, which may not be adaptive and precise due to the dynamic nature of Kubernetes environments. To overcome the limitations, we propose a systematic permission-oriented risk detection approach called KubeGuard. First, KubeGuard identifies a minimal permission set and uses it to check whether the existence of excessive permissions in the permission configurations. Second, KubeGuard detects various privilege escalation risks through dynamic rule-based auditing. Third, KubeGuard prevents sensitive resource leakages by monitoring the messages transferred between pods in Kubernetes and alerting in case sensitive resources are involved through the keyword matching. We further developed a supporting prototype called Kube-Guarder. Experiments were conducted on a suite of open-source Kubernetes applications and simulated scenarios to evaluate the effectiveness of KubeGuard. Experimental results have shown that KubeGuard can detect excessive permissions more effectively and precisely compared with the static rule-based baseline technique, and in the meanwhile, KubeGuard can detect various types of privilege escalation and sensitive resource leakage. As a result, this study delivered a promising technique for improving the security of Kubernetes applications.