Security Analysis of Camera-LiDAR Semantic-Level Fusion Against Black-Box Attacks on Autonomous Vehicles

To enable safe and reliable decision-making, autonomous vehicles (AVs) feed sensor data to perception algorithms to understand the environment. Sensor fusion, and particularly semantic fusion, with multi-frame tracking is becoming increasingly popular for detecting 3D objects. Recently, it was shown that LiDAR-based perception built on deep neural networks is vulnerable to LiDAR spoofing attacks. Thus, in this work, we perform the first analysis of camera-LiDAR fusion under spoofing attacks and the first security analysis of semantic fusion in any AV context. We find first that fusion is more successful than existing defenses at guarding against naive spoofing. However, we then define the frustum attack as a new class of attacks on AVs and find that semantic camera-LiDAR fusion exhibits widespread vulnerability to frustum attacks with between 70% and 90% success against target models. Importantly, the attacker needs less than 20 random spoof points on average for successful attacks - an order of magnitude less than established maximum capability. Finally, we are the first to analyze the longitudinal impact of perception attacks by showing the impact of multi-frame attacks.