Time Accuracy De-Synchronisation Attacks Against IEC 60870-5-104 and IEC 61850 Protocols

Accurate time synchronisation is a key requirement for control and automation protocols with (near) real time requirements such as the IEC 60870-5-104 and 61850 family of standards relying on IP transport, and also represents an attractive attack vector against power systems. We propose a modelling and analytical technique based on queueing theory and study model the behaviour of both protocol standard families for deliberately limited, weak adversaries. We demonstrate the efficacy of the model by identifying a way of undermining measurement and control signal QoS whilst remaining compliant with standards merely by varying inter-arrival rates of legitimate traffic, resulting in de-synchronisation.