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Researchers Turn Smartphone Vibration Motor Into Microphone To Spy On You (softpedia.com) 77

An anonymous reader writes from a report via Softpedia: Two researchers from the University of Illinois at Urbana-Champaign have come up with a method to turn smartphone vibration motors into makeshift microphones, capable of recording the sound around them. The attack relies on using the vibration motor's coil to record incoming sound waves, which are then transmitted to the attacker, who then uses a processing algorithm to enhance the signal by reconstructing high-frequency waves. This is needed because the vibra-motor can only pick up low-frequency sounds, up to 2 kHz. Their method doesn't yield perfect results (4 in 5 people can understand the sounds) and also needs physical access to the device, but it puts in place the theoretical details needed to carry out and refine such attacks in the future.
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Researchers Turn Smartphone Vibration Motor Into Microphone To Spy On You

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  • Paranoid much? (Score:1, Insightful)

    by Anonymous Coward

    No one is spying on you in this manner. These are the types of attacks that would be used by nations, not individuals. Why would anyone worry about this? It's a non-issue, especially because there are far easier ways to spy on most people. Besides, none of you are that interesting, no matter how much you might think otherwise.

  • You know... (Score:5, Funny)

    by Fwipp ( 1473271 ) on Tuesday June 07, 2016 @08:48PM (#52271875)

    It turns out that in addition to having vibration motors, smartphones also have regular microphones.

    Who'da thunk?

    • The original story might have been "your PAGER can hear you!"
    • Using the microphone that doesn't require "physical access to the device" sounds too easy for the hackers. They need new challenges.
    • Re:You know... (Score:4, Interesting)

      by Ungrounded Lightning ( 62228 ) on Wednesday June 08, 2016 @02:16AM (#52272809) Journal

      It turns out that in addition to having vibration motors, smartphones also have regular microphones.

      But if the security auditors are only looking for code that gets signals from the microphone, they might miss code that gets signals from the vibrator.

      Using the ringer for a room bug has been stock stuff since at least WWII. It has the advantage that it's connected to the line all the time and doesn't require any modification of the phone.

      The early electronic piezo-electric sounders, which replaced the electromechanical bell mechanisms, were even better microphones, too. (I recall the blurb on the box of the Unisonic model 7441, which was a two-line phone from about the mid '80s, which had one of each - a bell for line 1 and a piezo sounder for line two. The blurb was really funny: The C-suite character it was attributed to was bragging about being ex-FBI and how important it was to have a secure phone. B-) )

      • by Sneftel ( 15416 )

        But if the security auditors are only looking for code that gets signals from the microphone, they might miss code that gets signals from the vibrator.

        Sure, but this is a "requires physical access" hack, meaning the attacker could instead just tee the microphone into whatever ADC they were planning to wire the vibration motor into.

        Motors, piezo buzzers, etc. make decent microphones. *Microphones* make even better microphones. And there's one right there.

    • by Kkloe ( 2751395 )
      "Smart"-gear have vibration motors without having microphones
    • This was my immediate thought. Okay, you can do this, but why would you in the presence of much better sensors, especially ones that are already accessible via software?

  • Whoop de do. (Score:5, Informative)

    by msauve ( 701917 ) on Tuesday June 07, 2016 @08:51PM (#52271893)
    It requires much more than simple "physical access." They hardwired the vibration motor to an analog input.
    • While I don't disagree with your point, I think your missing how security research works.

      Next someone finds a viable way to read that analog input without rooting the phone, and then someone else discovers that while the analog input isn't physically connected to the vibrator ( no one uses motors anymore, just basic electromagnets) they can read enough of a ripple from it to decode audio ...

      Sounds silly but both the NSA and CIA have done far more with FAR less.

      Not all research yields immediate and direct r

      • by msauve ( 701917 )
        I understand how this "security research" works - some freshman college kids come up with a project worthy of honorable mention at a middle school science fair, and expect a good grade for it.

        You're an idiot, and don't understand how phones work. If they can read an analog input, they can read the microphone (most phones have multiple ones, even) directly. BTW, it is a motor, which only means it converts electrical energy to mechanical, it doesn't imply it spins. A common loudspeaker is also a motor.
  • by Jake73 ( 306340 ) on Tuesday June 07, 2016 @08:51PM (#52271899) Homepage

    ...why not just install a microphone connected to the LINE IN instead of wiring the vibration motor to it as they have done?

    • because a story saying that a hacked phone microphone could be used to listen to you would elicit the response of "No SHIT Sherlock" and people would move on without clicking on it. Far better to create an overly complex scenario that produces inferior results and is far harder to do but gets the clicks for "WTF"!
    • bothering to install a microphone

      on a cell phone

      mmmmkay you need to think a little harder

  • What's worse? (Score:1, Interesting)

    by subk ( 551165 )
    This dumb-ass "attack" or the fact that these clowns have jobs as researchers?
  • App permissions (Score:2, Insightful)

    by Anonymous Coward

    Apps should have to request access to vibration functions anyway. I'm sick of link-hijacking popunders that can vibrate my phone from through my browser.

  • by jenningsthecat ( 1525947 ) on Tuesday June 07, 2016 @09:22PM (#52272015)

    No one can "Spy On You" using this method on any stock production phone. The vibration motor is connected to an *output* of the chip that drives it, not an *input*. Additionally, that output is likely to be digital rather than analog, so even its direction could be magically reversed, the likelihood of the chip being able to process whatever signal the motor would produce in response to ambient sounds would be just about zero. And if someone was modifying your phone in order to hear your conversations, there are *much* easier, faster, more reliable, less convoluted ways of doing it - like piggybacking on the microphone that's already there.

    The ability to use a vibration motor as a microphone is a technical curiosity, but it's not at all surprising to anyone familiar with basic electrical and electronic concepts. The researchers' work is a nice proof-of-concept which may find useful application at some point. But really, the title of TFA, (and TFS), is solidly in the province of yellow journalism. There are more than enough *real* reasons to fear for our privacy - there's absolutely no need to further stoke that fire with false fears like those being promoted here.

    • by dbIII ( 701233 )
      I'm actually far more interested in how they can "enhance the signal by reconstructing high-frequency waves". Maybe that is the real story underneath the required hype for mainstream science reporting at the moment.
      Low frequencies travel very well (turn down the bass you bastards next door) while high frequency information is lost very easily.

      use a vibration motor as a microphone is a technical curiosity, but it's not at all surprising to anyone familiar with basic electrical and electronic concepts

      Geophon

      • by gweihir ( 88907 )

        This "enhancement" is not an enhancement. It consists of having a computer guess. If the computer guesses wrong, the sound quality is actually degraded. There is no technology in this universe than can reconstruct data that is missing from the signal, as that would require magic.

        • This "enhancement" is not an enhancement. It consists of having a computer guess

          Obviously, but in what way with what degree of success?

          There is no technology in this universe than can reconstruct data that is missing from the signal

          Sometimes there doesn't have to be but a workaround can be useful. As an example a few years ago I attended a presentation on Transmission Electron Microscopy on some structures in teeth related to tooth growth right down to the atomic level. Calcium atoms could not be imaged -

      • In the audio recording and processing industries it is very common to introduce synthetic higher frequencies. It is a longstanding result that such addition can improve vocal clarity. It is also commonly sed as a guitar effect. A good description of some of the processing techniques is found here: https://www.soundonsound.com/s... [soundonsound.com]
    • by tlhIngan ( 30335 )

      No one can "Spy On You" using this method on any stock production phone. The vibration motor is connected to an *output* of the chip that drives it, not an *input*. Additionally, that output is likely to be digital rather than analog, so even its direction could be magically reversed, the likelihood of the chip being able to process whatever signal the motor would produce in response to ambient sounds would be just about zero. And if someone was modifying your phone in order to hear your conversations, ther

  • It's not the same thing as the vibration device, but I wonder if at the top collection speed the accelerometer included in pretty much all modern smartphones has enough fidelity of measurement to record sound.. that would be interesting.

  • This is nonsense (Score:4, Informative)

    by gweihir ( 88907 ) on Tuesday June 07, 2016 @09:43PM (#52272089)

    If you can physically manipulate the device, plant a proper microphone. If not, this is irrelevant, as there is no A/D input connected to that motor. The whole thing is an utterly worthless stunt by "researchers" greedy for attention but lacking in actual scientific skill. Why does this get reported here?

    • my phone has a microphone built in! OMG what were the engineers thinking?

      • by gweihir ( 88907 )

        Rather obviously, this is about a microphone the OS does not know about or where the OS thinks it is something else. One could even say that this is exceptionally exceedingly massively obvious. But apparently still not obvious enough for some people.

        • nonsense.

          there are known ways to subvert all the common phone OS in use and take over phone functions including microphone.

          • by gweihir ( 88907 )

            ... and which this story is not about at all. Seriously.

            • correct, this story is about a stupid needless hack for which there are trivial means to get even better audio from the microphone a phone already has.

  • Attacker needs to borrow phone, split it open, add a bunch of wires and jumpers, put phone back together -- and then the quality is such that few people understand the words spoken.

    Great experiment - but I am missing the point. Sure is neat that this kind of device could be used. Might they instead extend the attack use a doorbell ringer or something?

  • because hackers want to be able to control a phone with a microphone.
    • because hackers want to be able to control a phone with a microphone.

      a phone without a microphone is what i mean.

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