Inaudible voice may control your smartphone

“Hey Siri, send a message to my mom and told her I might be a little bit late for dinner.”

“Hey Siri, tell me the nearest way from here to home.”

“Hey Siri, ……”

As time goes on, speech recognition system now becomes a basic function for most of the smartphones. The speech recognition system, also called the voice assistant, such as Siri from Apple and Cortana from Microsoft, has changed the way that we are using to control our smartphones. It has brought lots of convenience to us, especially when we are not able to touch the phone and typing commands to tell it what to do, like driving the car or washing the clothes.

Voice Assistant. Image Credit: pixabay

As we could use the voice assistant to make a phone call, send a message or even buy something online, it is important to make sure that the system is safe and the devices can only be activated by our own voice. The smartphone companies are quite confident with this because it is believed that the voice characters of a person are unique and very hard to simulate. For example, “Hey Siri” is a function of iPhone and it allows people to activate and control the device without entering the password. When we set up this function, we will be required to read some texts presented by the system aloud and the features of our voice will be recorded.

Using the feature identification method, voice assistant could restrict other people’s voice to control our smartphone. However, a recent research shows that an inaudible voice could take over your device without your notice. A group of researchers from Zhejiang University, one of the top universities in China, successfully using the ultrasound to activate and control the smartphones in an experiment.

Hacker / Attacker. Image Credit: pixabay

The ultrasound is a special kind of voice, which cannot be heard by the human because the frequency of it was beyond the human hearing range. However, the microphone inside the smartphone could catch this sound and transfer it into command signals. The researchers first recorded a person’s voice and transferred it into ultrasound, then they broadcast the voice to the smartphone. Surprisingly, the screen lights up and a phone call has been made followed by the “invisible commands”.

This method is named as a “Dolphin Attack”, as the dolphin’s voice is a kind of ultrasound. You could watch a demo here to see the experiment. The researchers are also trying to find some solutions to solve this problem. If you are interested in this topic and want to find something deeper, here is the paper for the research.

Although this problem seems to be serious, you should not be too worried about it. According to those scientist’s research, the attack is not very easy to implement, at least your neighbor might not be able to control your smartphone from their house.

If you are still worried about the problem, you could shut down the activated function of the voice assistant like “Hey Siri”. But just think about something good, maybe you could put a “Dolphin Attack” in your bag while attending a birthday party, and then all of your friend’s phone starts to play the birthday song……


8 Responses to “Inaudible voice may control your smartphone”

  1. Xuexiao Yang says:

    Haha, I also close the “Hey Siri” function after I’ve learned this info. But hope we could reopen it safely sonn~😄

  2. ke kang says:

    Great reading! I think i will close Siri after reading this blog.

  3. Xuexiao Yang says:

    Thanks for reading, Claudia! Actually this risk was discovered recently and will be discussing in a coming international information security conference. Hope the researchers could find out some good solutions for us to defend the attack.😄

  4. Claudia says:

    Hi Patrick, what an interesting read! It never occurred to me that phone speakers could pick up sounds other than what humans hear. This brings a whole new level to hacking, and trying to find ways of protecting yourself.

  5. Xuexiao Yang says:

    Thanks for your comment, Nadun! Yes, things like “attack and defense” always attracting the geeks to explore. And this should be an exciting journey!

  6. Nadun says:

    That was quite interesting and terrifying at the same time! It’s unfortunate that there always seems to be a way to bypass ones security, but -as “millera2” also mentioned- the lengths that people go to, and the methods that they use to hack into someones device never ceases to fascinate me.

  7. Xuexiao Yang says:

    Thanks for reading! And that’s right, it is quite frightening, especially we all have lots of personal info stored in the smart devices now.

  8. millera2 says:

    I always this information so interesting, hacking has a certain sense of mystery to it…. at the same time I guess that’s what makes it quite frightening!