MIT Researchers Discover the Dark Side of Light Sensors in Smartphones: How Hackers Can Spy on You Without Using the Camera

Researchers Uncover the Dark Side of Light Sensors on Smartphones

Researchers from MIT have discovered the dark side of light sensors in smartphones, which could help hackers track a user’s movements.

Privacy Concerns with Light Sensors

Researchers say your phone’s ambient light sensor could be used to spy on you, without turning on the camera at all.

These small sensors adjust the brightness of your screen based on the ambient light. But unlike cameras, apps don’t need your permission to access them.

As MIT researchers discovered, this seemingly innocent feature has a dark side, as hackers can exploit these sensors to reconstruct images of what’s happening right in front of your screen.

Risks and Vulnerabilities

Researchers at the Computer Science and Artificial Intelligence Laboratory (CSAIL) at the Massachusetts Institute of Technology (MIT) discovered that this sensor can also take pictures of your hand gestures and reveal your privacy.

To get a better understanding, imagine this situation: You are browsing a website, completely unaware that every swipe you make is captured, not by the camera, but by the light sensor. Or you are watching a movie with a friend, and you casually place your hand near the screen, it is possible that a hacker is collecting your interactions from afar.

Algorithm to Reconstruct Images

The researchers published a paper in the journal Science Advances earlier this month, proposing a computational imaging algorithm that can restore an image of the environment from the perspective of a display screen using subtle changes in light intensity detected by the sensor.

The MIT team, led by Yang Liu, developed an algorithm that analyzes minute changes in light intensity captured by the sensor when objects touch the screen.

Privacy Threat and Countermeasures

“Many believe that these sensors should always be on,” says lead author Yang Liu, from the Department of Electrical Engineering and Computer Science (EECS) and a PhD candidate in the Computer Science and Artificial Intelligence Laboratory.

The team showed how hackers can use this algorithm to spy on hand gestures, such as swiping or swiping, and infer how you interact with your phone while watching videos.

A third test found that users are also at risk when watching video clips such as movies and short clips. A human hand hovered in front of the sensor while scenes from the movie Tom and Jerry were displayed on the screen, with a white panel behind the user reflecting light onto the device. However, the ambient light sensor captured subtle changes in intensity for each video frame, with the resulting images visible to touch gestures.

“This work turns your device’s ambient light sensor and screen into a camera,” said Professor Felix Hyde from Princeton University, highlighting how widespread this vulnerability is and its malicious nature.

While phone cameras have raised privacy concerns for years, the ambient light sensor presents a unique challenge. Not only does it bypass permissions checks, its passive nature makes it virtually undetectable. It is possible to inadvertently broadcast your actions to an intruder even with the camera covered.

Recommended Countermeasures

The researchers suggest two critical countermeasures:

• Detailed app permissions: Users should have clear control over which apps can access the ambient light sensor, enabling them to decide who can peek into their digital lives.
• Downgrading the sensor: Limiting the accuracy and speed of the sensor reduces the information it collects, making it difficult for hackers to collect meaningful data.

Source: Interesting Engineering

The post MIT Researchers Discover the Dark Side of Light Sensors in Smartphones: How Hackers Can Spy on You Without Using the Camera appeared first on asumetech.

from Technology - asumetech https://asumetech.com/mit-researchers-discover-the-dark-side-of-light-sensors-in-smartphones-how-hackers-can-spy-on-you-without-using-the-camera/