Threat navigator: grouping and ranking malicious external threats to current and future urban smart grids

Deriving defensible belief statements about threat rankings for large and entangled systems, such as urban Smart Grids, is a formidable task. Suitable approaches should account for multiple threat events posed by different classes of attackers who target system components. Given the complexity of the task, a suitable level of guidance how to rank more relevant and filter out the less relevant threats would be desirable. This requires a method able to distill the list of all possible threat events in a traceable and repeatable way, given a set of assumptions on the attackers. The Threat Navigator proposed in this paper tackles this issue. Attacker profiles are describes in terms of Focus (linked to Actor-to-Asset relations) and Capabilities (Threat-to-Threat dependencies). The method is exercised on a sample urban Smart Grid. The obtained digest of ranked list of threat events is useful for a risk analysis that ultimately aims at finding cost-effective mitigation strategies.