CommanderGPS: Practical Hidden Command Dissemination Through Pedal Operations

It is critical to enable a driver to control in-vehicle devices (e.g., a smartphone) during driving, especially when the driver is in danger. Existing in-vehicle communication often relies on speech communication or hand operation. However, such an approach is not always available (e.g., if the phone is out of reach or the driver is monitored and forced not to use it), and may also bring safety concerns by diverting attention from driving. In this work, we investigate the possibility of disseminating commands for a driver through pedal operation and develop CommanderGPS, a system that utilizes pedal operation to control vehicle movement as a transmitter, while an in-vehicle GPS-equipped device, which can capture vehicle movement, as a receiver. The discovered communication modality is inconspicuous and safe because it does not require the driver to use their voice, take their hands off the wheel, or remove their foot from the pedals. It still allows the driver to engage in communication while driving. We implement CommanderGPS on top of commercial off-the-shelf (COTS) GPS-equipped mobile devices and conduct a suite of experiments to validate its feasibility, efficiency, and security. Extensive experimental results demonstrate that CommanderGPS could achieve a success rate of above 96% for transmitting Morse code and a comparable text input speed to other Morse code based input systems. Meanwhile, an attacker is unable to recover the disseminated commands by stalking the target vehicle.