  Cooperative Adaptive Cruise Control (CACC) is a technology that allows groups
of vehicles to form in automated, tightly-coupled platoons. CACC schemes
exploit Vehicle-to-Vehicle (V2V) wireless communications to exchange
information between vehicles. However, the use of communication networks brings
security concerns as it exposes network access points that the adversary can
exploit to disrupt the vehicles' operation and even cause crashes. In this
manuscript, we present a sensitivity analysis of CACC schemes against a class
of resource-limited attacks. We present a modelling framework that allows us to
systematically compute outer ellipsoidal approximations of reachable sets
induced by attacks. We use the size of these sets as a security metric to
quantify the potential damage of attacks affecting different signals in a
CACC-controlled vehicle and study how two key system parameters change this
metric. We carry out a sensitivity analysis for two different controller
implementations (as given the available sensors there is an infinite number of
realizations of the same controller) and show how different controller
realizations can significantly affect the impact of attacks. We present
extensive simulation experiments to illustrate the results.
