Trapped by Their Own Light: Deployable and Stealth Retroreflective Patch Attacks on Traffic Sign Recognition Systems

TL;DR

This paper introduces the Adversarial Retroreflective Patch (ARP), a stealthy and deployable attack on traffic sign recognition systems that uses retroreflective materials activated by vehicle headlights, achieving high success rates and maintaining stealth.

Contribution

The paper presents ARP, a novel retroreflective patch attack combining deployability and stealth, along with a simulation method and a defense strategy using polarized filters.

Findings

ARP achieves ≥93.4% success rate at 35 meters in dynamic scenarios.

ARP maintains near-identical stealthiness to benign signs.

DPR Shield defense achieves ≥75% success against micro-prism patches.

Abstract

Traffic sign recognition plays a critical role in ensuring safe and efficient transportation of autonomous vehicles but remain vulnerable to adversarial attacks using stickers or laser projections. While existing attack vectors demonstrate security concerns, they suffer from visual detectability or implementation constraints, suggesting unexplored vulnerability surfaces in TSR systems. We introduce the Adversarial Retroreflective Patch (ARP), a novel attack vector that combines the high deployability of patch attacks with the stealthiness of laser projections by utilizing retroreflective materials activated only under victim headlight illumination. We develop a retroreflection simulation method and employ black-box optimization to maximize attack effectiveness. ARP achieves $\geq$93.4\% success rate in dynamic scenarios at 35 meters and $\geq$60\% success rate against commercial TSR systems in real-world conditions. Our user study demonstrates that ARP attacks maintain near-identical stealthiness to benign signs while achieving $\geq$1.9\% higher stealthiness scores than previous patch attacks. We propose the DPR Shield defense, employing strategically placed polarized filters, which achieves $\geq$75\% defense success rates for stop signs and speed limit signs against micro-prism patches.