Time to Rethink the Design of Qi Standard? Security and Privacy Vulnerability Analysis of Qi Wireless Charging

Abstract

With the ever-growing deployment of Qi wireless charging for mobile devices, the potential impact of its vulnerabilities is an increasing concern. In this paper, we conduct the first thorough study to explore its potential security and privacy vulnerabilities. Due to the open propagation property of electromagnetic signals as well as the non-encrypted Qi communication channel, we demonstrate that the Qi communication established between the charger (i.e., a charging pad) and the charging device (i.e., a smartphone) could be non-intrusively interfered with and eavesdropped. In particular, we build two types of attacks: 1) Hijacking Attack: through stealthily placing an ultra-thin adversarial coil on the wireless charger’s surface, we show that an adversary is capable of hijacking the communication channel via injecting malicious Qi messages to further control the entire charging process as they desire; and 2) Eavesdropping Attack: by sticking an adversarial coil underneath the surface (e.g., a table) on which the charger is placed, the adversary can eavesdrop Qi messages and further infer the device’s running activities while it is being charged. We validate these proof-of-concept attacks using multiple commodity smartphones and 14 commonly used calling and messaging apps. The results show that our designed hijacking attack can cause overcharging, undercharging, and paused charging, etc., potentially leading to more significant damage to the battery (e.g., overheating, reducing battery life, or explosion). In addition, the designed eavesdropping attack can achieve a high accuracy in detecting and identifying the running app activities (e.g., over 95.56% and 85.80% accuracy for calling apps and messaging apps, respectively). Our work brings to light a fundamental design vulnerability in the currently-deployed wireless charging architecture, which may put people’s security and privacy at risk while wirelessly recharging their smartphones.