Invisible Smoke: Analyzing and Enhancing the Security of Smoke Detectors Under Intentional Electromagnetic Interference.

Smoke detectors are pivotal sensors in fire protection systems, serving as the primary trigger for alarm mechanisms and structural fire-response strategies. Their security is fundamental to the stable operation of the entire fire-protection infrastructure. This paper investigates the manipulation of commercial smoke detectors through the injection of Intentional Electromagnetic Interference (IEMI), which can induce false alarms or suppress alarms even in the presence of smoke. Our core insight is that, despite rigorous Electromagnetic Compatibility (EMC) testing, the button and amplification circuits in the detector architectures evaluated in this study can remain susceptible to coupling with IEMI attack signals. We validated these threats on nine gas sensors and seven off-the-shelf commercial smoke detectors, achieving an attack distance of over 3 m with a total power maintained within 50 W. We further observed similar IEMI-induced effects in the additional gas-detection devices evaluated in this study, including an alcohol detector, a toxic gas detector, and an air-quality detector. Finally, we propose both hardware- and software-based countermeasures to mitigate these risks.