Automated security analysis of a SCADA system

Sammanfattning: Supervisory control and data acquisition (SCADA) is a computer system for analysing, and monitoring data, as well as, controlling a plant in industries such as power grids, oil, gas refining, and water control. SCADA belongs to the category of critical systems that are needed to maintain the infrastructure of cities and households. Therefore, the security aspect of such a system has a significant role. The early SCADA systems were designed with the operation as the primary concern rather than security since they were a monolithic networked system without external access. However, the systems evolved, and SCADA systems were embedded with web technologies for users to monitor the data externally. These changes improved the efficiency of monitoring and productivity; however, this caused a problem of potential cyber-attacks to a SCADA system. One such example was Ukraine’s power grid blackout in 2015. Therefore, it is beneficial for the security of a SCADA system to create a threat modeling technique that can understand the critical components of SCADA, discover potential threats, and propose possible mitigation strategies. One issue when creating a threat model is the significant difference of SCADA from traditional Operational Technology (OT) systems. Another significant issue is that SCADA is a highly customisable system, and each SCADA instance can have different components. Therefore, for this work, we implemented a threat modeling language scadaLang, which is specific to the domain of a SCADA system. We started by defining the major assets of a SCADA system, attackers, entry surfaces, and built attacks and defense strategies. Then we developed a threat modeling domain-specific language scadaLang that can create a threat model for a particular instance of SCADA taking the differences in components and connections into account. As a result, we achieved a threat modeling language for SCADA, ensured the reliability of the results by peer-reviewing of an engineer familiar with the domain of the problem, and proposed a Turing test to ensure the validity of the result of scadaLang as the future development of the project.