Rain-Reaper: Unmasking LiDAR-based Detector Vulnerabilities in Rain

LIDAR-based 3D object detection aims to enhance the situational awareness of autonomous vehicles. Despite recent advancements in this technology, there has been evidence that the susceptibility of 3D object detectors to signal spoofing is high, leading to the erroneous detection of "ghost objects" or the failure to detect genuine ones. While prior work has investigated the design of these new attacks and new defenses, the effect of weather conditions, which is a hot topic in autonomous vehicle research, on both attacks and defenses has never been studied. Inspired by this observation, in this paper, we present a novel genetic algorithm-based attack, entitled Rain-Reaper, that leverages on the effect of rain and identifies critical detection points used by 3D detectors. We show that adverse weather conditions not only diminish detection distance and accuracy but also expose the limitations of existing defenses. We have found that the unique characteristics of wet roads lead to underperforming defenses, thus, leading to a false sense of confidence in them. The effectiveness and efficiency of the attack and the robustness of the defenses have been evaluated with both simulated and real data. Our Rain-Reaper demonstrates a high attack success rate while successfully evading existing defenses with an adversarial point budget of up to 8.8 times smaller than previously demonstrated state-of-the-art attacks.