STRIDE-based threat modeling for cyber-physical systems

TLDR

Critical infrastructures and industrial control systems are complex CPS, and reliable operation requires comprehensive threat modeling during design and validation, yet existing work focuses mainly on safety and hazards, leaving cyber vulnerabilities and the impact of attacks on physical processes insufficiently understood. This study introduces a comprehensive STRIDE-based threat modeling framework for CPS and examines the threat types that can arise in each component and how component vulnerabilities can jeopardize overall system security. The authors devise a practical STRIDE application methodology and validate it on a laboratory synchrophasor-based synchronous islanding testbed. The results show that STRIDE is a lightweight, effective threat modeling approach that simplifies vulnerability identification and enables component-level security planning during system design.

Abstract

Critical infrastructures and industrial control systems are complex Cyber-Physical Systems (CPS). To ensure reliable operations of such systems, comprehensive threat modeling during system design and validation is of paramount significance. Previous works in literature mostly focus on safety, risks and hazards in CPS but lack effective threat modeling necessary to eliminate cyber vulnerabilities. Further, impact of cyber attacks on physical processes is not fully understood. This paper presents a comprehensive threat modeling framework for CPS using STRIDE, a systematic approach for ensuring system security at the component level. This paper first devises a feasible and effective methodology for applying STRIDE and then demonstrates it against a real synchrophasor-based synchronous islanding testbed in the laboratory. It investigates (i) what threat types could emerge in each system component based on the security properties lacking, and (ii) how a vulnerability in a system component risks the entire system security. The paper identifies that STRIDE is a light-weight and effective threat modeling methodology for CPS that simplifies the task for security analysts to identify vulnerabilities and plan appropriate component level security measures at the system design stage.