Using ultrasound waves propagating through a solid surface, researchers were able to read text messages and make fraudulent calls on a cellphone sitting on a desk up to 30 feet away.

Attacks on cell phones aren’t new, and researchers have previously shown that ultrasonic waves can be used to deliver a single command through the air.

However, new research from Washington University in St. Louis expands the scope of vulnerability that ultrasonic waves pose to cellphone security. These waves, the researchers found, can propagate through many solid surfaces to activate voice recognition systems and — with the addition of some cheap hardware — the person initiating the attack can also hear the phone’s response.

The results were presented Feb. 24 at the Network and Distributed System Security Symposium in San Diego.

«We want to raise awareness of such a threat,» said Ning Zhang, assistant professor of computer science and engineering at the McKelvey School of Engineering. «I want everybody in the public to know this.»

Zhang and his co-authors were able to send «voice» commands to cellphones as they sat inconspicuously on a table, next to the owner. With the addition of a stealthily placed microphone, the researchers were able to communicate back and forth with the phone, ultimately controlling it from afar.

Story Source: Materials provided by Washington University in St. Louis. Original written by Brandie Jefferson. Note: Content may be edited for style and length.