Title: FIRED: Frequent Inertial Resets with Diversification for Emerging Commodity Cyber-Physical Systems,
Abstract: A Cyber-Physical System (CPS) is defined by its unique characteristics
involving both the cyber and physical domains. Their hybrid nature introduces
new attack vectors, but also provides an opportunity to design new security
defenses. In this paper, we present a new domain-specific security mechanism,
FIRED, that leverages physical properties such as inertia of the CPS to improve
security.
FIRED is simple to describe and implement. It goes through two operations:
Reset and Diversify, as frequently as possible -- typically in the order of
seconds or milliseconds. The combined effect of these operations is that
attackers are unable to gain persistent control of the system. The CPS stays
safe and stable even under frequent resets because of the inertia present.
Further, resets simplify certain diversification mechanisms and makes them
feasible to implement in CPSs with limited computing resources.
We evaluate our idea on two real-world systems: an engine management unit of
a car and a flight controller of a quadcopter. Roughly speaking, these two
systems provide typical and extreme operational requirements for evaluating
FIRED in terms of stability, algorithmic complexity, and safety requirements.
We show that FIRED provides robust security guarantees against hijacking
attacks and persistent CPS threats. We find that our defense is suitable for
emerging CPS such as commodity unmanned vehicles that are currently unregulated
and cost sensitive.