[en] Time-triggered real-time systems achieve deterministic behavior using schedules that are constructed offline, based on scheduling constraints. Their deterministic behavior makes time-triggered systems suitable for usage in safety-critical environments, like avionics. However, this determinism also allows attackers to fine-tune attacks that can be carried out after studying the behavior of the system through side channels, targeting safety-critical victim tasks. Replication – i.e., the execution of task variants across different cores – is inherently able to tolerate both accidental and malicious faults (i.e. attacks) as long as these faults are independent of one another. Yet, targeted attacks on the timing behavior of tasks which utilize information gained
about the system behavior violate the fault independence assumption fault tolerance is based on.
This violation may give attackers the opportunity to compromise all replicas simultaneously, in par-
ticular if they can mount the attack from already compromised components. In this paper, we ana-
lyze vulnerabilities of time-triggered systems, focusing on safety-certified multicore real-time systems. We introduce two runtime mitigation strategies to withstand directed timing inference based attacks: (i) schedule randomization at slot level, and (ii) randomization within a set of offline constructed schedules. We evaluate these mitigation strategies with synthetic experiments and a real case study to show their effectiveness and practicality.
Disciplines :
Computer science
Author, co-author :
Krüger, Kristin; Technische Universität Kaiserslautern > Department of Electrical and Computer Engineering
Vreman, Nils; Lund University > Department of Automatic Control
Pates, Richard; Lund University > Department of Automatic Control
Maggio, Martina; Lund University > Department of Automatic Control ; Saarland University > Department of Computer Science
Volp, Marcus ; University of Luxembourg > Interdisciplinary Centre for Security, Reliability and Trust (SNT) > CritiX
Fohler, Gerhard; Technische Universität Kaiserslautern > Department of Electrical and Computer Engineering
External co-authors :
yes
Language :
English
Title :
Randomization as Mitigation of Directed Timing Inference Based Attacks on Time-Triggered Real-Time Systems with Task Replication