Cyber Security Threat Modeling of Power Grid Substation Automation Systems

QC 20250502

Abstract

The substation is a vital part of the power grid and serves to aid in the distribution of electricity by, for example, transforming from high to low voltage. It is essential to protect the substation as a loss of electricity would cause severe consequences for our society. The Substation Automation System (SAS) allows for remote management and automation of substations but also creates possibilities for cybersecurity threats. In this thesis efforts towards using threat modeling to assess the cybersecurity of SAS are presented. Threat modeling entails creating a model of the system that shows the possible cybersecurity threats against it. To reach this goal, previously used information sources for threat modeling in the power systems domain are found. The thesis also includes the creation of a Time-To-Compromise (TTC) estimate for cyber attacks against Industrial Control Systems. By estimating the TTC, it is possible to prioritize which attacks to defend against. One method of creating threat models is by using threat modeling languages in which the assets, associations, attacks, and defenses have been defined. In this thesis, a threat modeling language for creating threat models of SAS is presented. The threat models in this thesis are used to create attack graphs to show the possible paths an attacker could take throughout the system. The work of this thesis also consists of evaluation of threat modeling languages that have been created or used. As a result, accurate assessment of cybersecurity for SAS can be made that helps in the efforts to keep them secure against cyber attacks.

urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-362974