Extended Abstract: Assessing GNSS Vulnerabilities in Smart Grids

For the future power grid, the need for time-synchronized measurement data of high resolution also comes with the drawback of an increasing reliance on Global Navigation Satellite Signals (GNSSs) for time synchronization. Although the manipulation of GNSS signals has been extensively investigated, the question of risk magnitude of such attacks on the power grid is still open: Apart from proof-of-principle examples that require the attacker to have profound knowledge of the system, the risk to real world systems remains largely undetermined. In this paper, we present a vulnerability analysis of a time server used in International Electrotechnical Commission (IEC) 61850-based substations to five GNSS spoofing attacks. We demonstrate that using a GNSS simulator, both quick-conspicuous and slow-stealthy attacks are successful. We assess the difficulty in the scope of a qualitative risk assessment. Our findings can support quantitative risk analysis, and hence decision-makers in ensuring grid stability.