Cybersecurity experts warn about what's happening with cell phones: "Calls can be remotely monitored with vibrations."

Phone calls can be remotely monitored through vibration recording, a type of cyberthreat demonstrated by a group of researchers at Pennsylvania State University (United States).

When talking on a cell phone, the device emits vibrations that are usually invisible to humans, but which can be captured by remote radars. With the help of artificial intelligence, specifically machine learning, these vibrations can be transcribed.

This is a potential type of cyberattack that researchers have studied to understand future risks to people's privacy, and which they presented at the ACM WiSec 2025 cybersecurity conference.

In their research, they used a millimeter-wave radar sensor placed a few meters from a mobile phone to record the vibrations of a call. They subsequently analyzed these vibrations using an adapted version of Whisper, an open-source language model designed for speech recognition.

Using this technique, they were able to decipher what was said in the conversation with 60 percent accuracy , as reported in a statement shared by the University. This accuracy, although currently low, could improve with the addition of manual corrections based on context, provided there is prior knowledge of the conversation.

"Similar to how lip readers can use limited information to interpret conversations, our model's results, combined with contextual information, allow us to infer fragments of a phone conversation from a few meters away," said Suryoday Basak, first author of the research.