‘Surfing attack’ hacks Siri, Google with ultrasonic waves

Ultrasonic waves don’t make a sound, but they can still activate Siri on your cellphone and have it make calls, take images or read the contents of a text to a stranger. All without the phone owner’s knowledge.

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.”