Inaudible ultrasound attack can stealthily control your phone, smart speaker

American university researchers have developed a novel attack called “Near-Ultrasound Inaudible Trojan” (NUIT) that can launch silent attacks against devices powered by voice assistants, like smartphones, smart speakers, and other IoTs.

The team of researchers consists of professor Guenevere Chen of the University of Texas in San Antonio (UTSA), her doctoral student Qi Xia, and professor Shouhuai Xu of the University of Colorado (UCCS).

The team¬†demonstrated NUIT attacks¬†against modern voice assistants found inside millions of devices, including Apple’s Siri, Google’s Assistant, Microsoft’s Cortana, and Amazon’s Alexa, showing the ability to send malicious commands to those devices.

Inaudible attacks

The main principle that makes NUIT effective and dangerous is that microphones in smart devices can respond to near-ultrasound waves that the human ear cannot, thus performing the attack with minimal risk of exposure while still using conventional speaker technology.

In a post on USTA’s site, Chen explained that NUIT could be incorporated into websites that play media or YouTube videos, so tricking targets into visiting these sites or playing malicious media on trustworthy sites is a relatively simple case of social engineering.

The researchers say the NUIT attacks can be conducted using two different methods.

The first method, NUIT-1, is when a device is both the source and target of the attack. For example, an attack can be launched on a smartphone by playing an audio file that causes the device to perform an action, such as opening a garage door or sending a text message.

The other method, NUIT-2, is when the attack is launched by a device with a speaker to another device with a microphone, such as a website to a smart speaker.

Source: Inaudible ultrasound attack can stealthily control your phone, smart speaker

This is like smart units like Amazon Echo / Alexa being controlled by TV commercials

Robin Edgar

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