Enabling Trusted Scheduling in Embedded Systems

The growing complexity and increased networking of securi-ty and safety-critical systems expose them to the risk of ad-versarial compromise through remote attacks. These attacks can result in full system compromise, but often the attacker gains control only over some system components (e.g., a pe-ripheral) and over some applications running on the system. We consider the latter scenario and focus on enabling on-schedule execution of critical applications that are running on a partially compromised system — we call this trusted scheduling. We identify the essential properties needed for the realization of a trusted scheduling system and we design an embedded system that achieves these properties. We show that our system protects not only against misbehav-ing applications but also against attacks by compromised peripherals. We evaluate the feasibility and performance of our system through a prototype implementation based on the AVR ATmega103 microcontroller. 1