Dangers Behind Charging VR Devices: Hidden Side Channel Attacks via Charging Cables

Abstract

Virtual reality (VR), offering 3D visuals and stereophonic sounds, significantly enhances users’ immersive experiences and has become a milestone in the era of the metaverse. However, due to the limited battery capacity of VR devices, it is common for users to rely on charging cables, which serve the dual purpose of power supply and audio output, to recharge their VR devices while in use. In this study, we propose an inconspicuous and stealthy side channel attack, coined as LineTalker, which can unveil visual-related and audio-related activities from VR devices during the charging process. The insight behind LineTalker is rooted in the observation that visual-related activities (e.g., 3D image rendering) are power-intensive and result in fluctuations in the current strength of the cable’s power supply line, which can be leveraged as side channel information. Similarly, audio-related activities (e.g., playing music) leave traces on the cable’s audio output line. Rather than providing a user with a compromised charging cable (i.e., embedding a current sensor) to measure the current strength, to make the attack less conspicuous, LineTalker employs the Hall effect to indirectly access side channel information. This is achieved by capturing magnetic signals using a Hall sensor placed near the target cable in a contactless manner. Experimental results demonstrate that LineTalker achieves an overall accuracy of 94.60% and 64.38% in inferring user activities in VR devices with intrusive and non-intrusive attack manners, respectively.