Every so often a vulnerability or risk to the security of our smartphones is discovered. Now, a new one has been revealed: that which concerns ultrasonic waves, waves that are beyond the reach of the human ear.
New research conducted by the University of Washington, in collaboration with Michigan State University, the University of Nebraska-Lincoln, and the Chinese Academy of Sciences, looks at how hackers can use them to activate Siri on an iPhone and get it to the smartphone make calls, take photos or read the content of a text to a third person. And all this, of course, without the knowledge of its owner.
The researchers warn that ultrasonic waves can propagate through many solid surfaces, activating voice recognition systems. Using inexpensive hardware , attackers can send these waves to surrounding mobiles easily.
Ning Zhang, a researcher and scientist involved in the study, commented: “We want to raise awareness about such a threat. I want the whole public to know about her ”.
A valid attack on any type of table
Any hacker could sit next to us and, without our realizing it, send out ultrasonic waves that would be interpreted by the microphone of the phones they want to attack. “If you know how to play with the signals, you can manipulate them so that when the phone interprets the incoming sound waves, it thinks it is receiving a command,” Zhang adds.
In order to test the capacity of these waves, the researchers organized a series of experiments in which the phone would have been placed on a table. On one side of it they put a microphone and a piezoelectric transducer, which converts electricity into ultrasonic waves. In the other, they hid a generator to emit the signals necessary for the hack.
This risk or vulnerability is not something that concerns a specific phone or model, but rather it is something general. To demonstrate the effectiveness of the experiment and the dangers it poses, the team tested 17 different models of smartphones , including devices from Apple, Samsung and Motorola. All but two were shown to be vulnerable to attack by ultrasonic waves.
The researchers also experimented with different table surfaces and terminal configurations. They changed the position of the mobiles several times and their orientation to test what was happening. And they even put other objects on the table to try to dampen the force of the waves. It was all in vain. “We did it in metal. We made it in glass. We did it in wood ”, he emphasizes. On plastic tables they were also effective, albeit a little less reliably.
According to the experiment, the ultrasonic waves could have hacking range in a radius of up to 30 feet . And, in addition, each attack could simultaneously affect more than one phone. The academics who carried out the research emphasize that it is a peculiar attack, which would be halfway between the digital or cyber world and the physical world.
