Improving Security for Time-Triggered Real-Time Systems against Timing Inference Based Attacks by Schedule Obfuscation

Covert timing channels in real-time systems allow adversaries to not only exfiltrate application secrets but also to mount timing inference based attacks. Much effort has been put into improving real-time system predictability with the additional benefit of reducing the former class of confidentiality attacks. However, the more predictable the system behaves, the easier timing inference based attacks become. Time-triggered scheduling is particularly vulnerable to these types of attacks due to offline constructed tables that are scheduled with clock synchronization and OS-timer predictability. In this paper, we obfuscate timetriggered scheduling to complicate timing inference based attacks while maintaining strong protection against exfiltration attacks