Imagine browsing a website, unaware that every scroll is being captured, not by the camera, but by the light sensor in your mobile phone. Or watching a movie with a friend, casually placing your hand near the screen, only for infiltrators to remotely collect your interactions.

Researchers from the Massachusetts Institute of Technology (MIT) have discovered that the light sensors in smartphones can assist infiltrators in tracking user movements without the use of the camera.

Led by Yang Liu, the institute's team developed an algorithm that analyzes subtle changes in the light intensity captured by the sensor when objects touch the screen. The algorithm reconstructs pixelated images by aggregating these fluctuations, revealing gestures like scrolling and swift transitions.

The team demonstrated how infiltrators could utilize this algorithm to spy on hand gestures, such as scrolling or quick transitions, and deduce how users interact with their phones while watching videos.

For instance, applications with screen access, like video players and web browsers, could potentially exploit this technology to gather user data without permission.

Through the ambient light sensor, malicious entities can eavesdrop on real-time user interactions with their devices. The problem with the light sensor issue lies in its ability to bypass permission checks. Its passive nature makes it practically undetectable, potentially broadcasting unintentional actions to infiltrators even with the camera covered.

The implications of this discovery highlight the need for enhanced privacy measures and greater awareness among users regarding the potential vulnerabilities in their smartphones.