  Current vehicular Intrusion Detection and Prevention Systems either incur
high false-positive rates or do not capture zero-day vulnerabilities, leading
to safety-critical risks. In addition, prevention is limited to few primitive
options like dropping network packets or extreme options, e.g., ECU Bus-off
state. To fill this gap, we introduce the concept of vehicular Intrusion
Resilience Systems (IRS) that ensures the resilience of critical applications
despite assumed faults or zero-day attacks, as long as threat assumptions are
met. IRS enables running a vehicular application in a replicated way, i.e., as
a Replicated State Machine, over several ECUs, and then requiring the
replicated processes to reach a form of Byzantine agreement before changing
their local state. Our study rides the mutation of modern vehicular
environments, which are closing the gap between simple and resource-constrained
"real-time and embedded systems", and complex and powerful "information
technology" ones. It shows that current vehicle (e.g., Zonal) architectures and
networks are becoming plausible for such modular fault and intrusion tolerance
solutions,deemed too heavy in the past. Our evaluation on a simulated
Automotive Ethernet network running two state-of-the-art agreement protocols
(Damysus and Hotstuff) shows that the achieved latency and throughout are
feasible for many Automotive applications.
