back to article Drops the mic... Hang on, hackers could be listening through my headphones?

Experimental malware has highlighted the possibility that hackers might be able to turn headphones into microphones in order to snoop on computer users. Research by computer scientists at Ben-Gurion University, Israel, has revealed that both headphones and loudspeakers present a potential bugging risk. The boffins put together …

  1. Mage Silver badge

    Odd

    That implies the sound chip connects to speaker(s) directly (maybe class D), in the past the sound chip used a separate analogue amp to drive the speakers, which as they point out, blocks the attack.

    Strange too, that the pins are reprogrammable, like a PIC micro etc.

    What next? The LCD screen capacitance sensed and thus acting as microphone?

    1. Scott Broukell

      Re: Odd

      "What next? The LCD screen capacitance sensed and thus acting as microphone?"

      Sssh!, not so loudly.

      1. Allan George Dyer Silver badge
        Coat

        Re: Odd

        "Sssh!, not so loudly."

        Too late, HAL's already reading your lips on the webcam.

        I'll get my spacesuit... with the helmet.

        1. Scott Broukell

          Re: Odd

          That's no webcam, it's a really cool miniature retro-design LED desk lamp, or, or is it . . .

    2. Dave 126 Silver badge

      Re: Odd

      A lot of PCs have retaskable audio jacks at the hardware level - but the firmware and drivers differ between models. Some PCs would bring up a port selection dialogue when a 3.5mm plug was inserted.

      I have spent a few minutes seeing if can do the same - my headphone jack is damaged, so it would suit me to reassign the microphone port. However, it would probably be quicker for me to open the machine and re-solder the port than it would to faff around with software and drivers. As far as I can make out, the IDT drivers allowed port remapping in XP, but don't in Win 7. Screwdriver time...

      Oh, just to clarify, Class D amplifiers are not 'digital', though people often refer to them as such.

      1. Ole Juul

        Re: Odd

        I don't use laptops, but I've noticed that they mostly have one jack now, instead of two. Also, I guess I'm getting old, we used to use speakers as microphones when I was a kid because we didn't have all the stuff kids have nowadays.

        1. Dave 126 Silver badge

          Re: Odd

          >Also, I guess I'm getting old, we used to use speakers as microphones when I was a kid because we didn't have all the stuff kids have nowadays.

          Same here. First, I discovered that microphone worked as a speaker, when I was about 7 year old. Later, I used some earbuds to record sound onto a Mac LCIII at school. Certainly not hi-fi quality, but speech was comprehensible.

          Also, the port remapping isn't unheard of - many XP-era desktops would present a dialogue asking what kind of device had just been plugged in. Of course, this facility in hardware doesn't translate to helping me right here and now remap my unused mic jack as an audio out.

          1. Anonymous Coward
            Anonymous Coward

            Re: Odd

            Same here. First, I discovered that microphone worked as a speaker, when I was about 7 year old. Later, I used some earbuds to record sound onto a Mac LCIII at school. Certainly not hi-fi quality, but speech was comprehensible.

            Same here. I made a tin-cans-and-string replacement at that age using only two 150Ω speakers and 25m of cable - no batteries or electronics needed :).

        2. GrumpyOldMan

          Re: Odd

          Yeah - we did the same - was just thinking that.

      2. anonymous boring coward Silver badge

        Re: Odd

        "my headphone jack is damaged, so it would suit me to reassign the microphone port"

        You know there are headers on the motherboard providing extra audio connectors?

    3. Simon Harris

      Re: Odd

      This datasheet from RealTek

      http://realtek.info/pdf/ALC888_1-0.pdf

      appears to show (section 4) that each audio channel is actually 'general purpose' in its design with output and input amplifiers.

      1. bombastic bob Silver badge
        Facepalm

        Re: Odd

        "each audio channel is actually 'general purpose' in its design with output and input amplifiers."

        no good deed (totally programmable audio channels) goes unpunished [being used for exploits]

        BOM cost just went up by a dollar, to add a couple of power amps between audio chip and speakers/headphones, to stop this.

    4. FuzzyTheBear
      Pint

      Re: Odd

      Note that this is as old as the world, speakers have been used as mics in intercom systems as long as i can remember. The way they exploit with the realtek ( of which i have one ) is kind of funny .. let em listen to the input noise of my power amp ,see if i care :)

  2. Pascal Monett Silver badge

    "take advantage of the physical properties of the connected equipment"

    Too often do we forget what it is we actually use, so deep is the habit of just considering what it does.

    This is truly what is called thinking out of the box. Kudos to the team that put this experiment together.

    I have no idea what the impact could be though. Granted, there is some pretty intelligent scum out there, and the NSA must be paying great attention, but I can't see that this is going to be a risk to the general public. Your run-of-the-mill scammer is not going to waste time setting up an entire software chain and phone-home capability just to hear traffic, crowds or people burping and farting.

    1. 142

      Re: "take advantage of the physical properties of the connected equipment"

      I'll agree there's little risk to the public from untargeted malware and scams.

      But for more targeted attacks, especially corporate focused ones, it would be very useful.

  3. John 110
    Joke

    I think I'll just.....

    ...muffle these here microphones with me ears...

    bootnote: Use your search engine of choice to google (oops) "exploding head syndrome"

    1. Natalie Gritpants Silver badge

      Re: I think I'll just.....

      Don't do that, your health insurance provider will work out how much coffee you drink.

  4. Paul Westerman
    Facepalm

    Wait..

    Are you telling me headphones are transducers now?

  5. J P

    Oh great

    So now I need to damp the speaker cones down with blutac as well as having masking tape across the camera?

  6. David Nash

    Can this apply to built-in speakers, or only headphones/speakers attached to the external jack?

    1. Anonymous Coward
      Anonymous Coward

      In theory (not having read the particulars) the built-in speakers would go through the same audio channels and -being both small/light and firmly fixed in the chassis- built-in speakers would be the target of choice for good audio by the attackers...they aren't going to be muffled by ears like headphones and they are going to be more sensitive than a couple of floor-monsters that don't move until you slam 300W through them.

      1. Pompous Git Silver badge

        going to be more sensitive than a couple of floor-monsters that don't move until you slam 300W through them.
        That 300W is for the low end. Mid-range and high frequencies don't need anywhere near that and those are the frequencies of interest. The real difficulty is transferring the information those transducers are already picking up to where they can be useful.

  7. TheProf Silver badge
    Devil

    Listening in

    Just as well laptops don't come with a built-in microphone.

    1. cortland

      Re: Listening in

      Whoops! The Surface Pro 3 certainly does.

    2. Anonymous Coward
      Anonymous Coward

      Re: Listening in

      Just as well laptops don't come with a built-in microphone that we know of.

  8. Anonymous Coward
    Anonymous Coward

    I wonder...

    Even if the scum could get the dodgy code on to your computer to do this little stunt, wouldn't the user be able to tell when the audio attempting to play didn't work? If the scum are using the speakers as microphones then they shouldn't work as *speakers* at the same time, correct? So if your speakers suddenly stop working then it's time to grab a fresh set of drivers from the manufacturer's site? Or, I dunno, unplug the speakers...

    1. Jon 37

      Re: I wonder...

      With appropriate software, they could use the speakers for bugging you most of the time, then switch them back into speaker mode automatically when you play audio.

      I don't think the exploit does that at the moment, but it's just a matter of writing the code.

      1. Disk0

        Re: I wonder...

        if they can hack your headphones they'll most likely have hacked your mic too... An intrepid developer might even be able to listen in while you are playing music by comparing the signal feed and return.

  9. 2+2=5 Silver badge
    Boffin

    James Bond

    So when James Bond turned on the radio and ran the shower in his hotel room to mask his conversation, we now see that Ian Fleming was ahead of his time.

    1. Anonymous Coward
      Anonymous Coward

      Re: James Bond

      Not really, the concept of using listening devices has been around for a very long time, conversely, the idea of making sound to mask any potential bugging device has also been around a long time.

    2. LDS Silver badge

      Re: James Bond

      No, the shower was just to warm the water for the next girl....

  10. Lith

    Hardware solutions include

    Unplugging the headphones?

  11. anonymous boring coward Silver badge

    ""Malware can use a computer as an eavesdropping device, even when a microphone is not present, muted, taped or turned off,"

    Taped? Because sound doesn't go through tape?

    Or did they get that mixed up with the camera?

    I'm willing to bet that a taped condenser mic will perform better than a pair of headphones -as a microphone, of course...

  12. Enric Martinez

    They won't dare to hack mine ;)

    Unless they enjoy happy tunes like Devourment's "Molesting the decapitated" or fancy some lovely Bestial Warlust ;)

    Hail \m/

  13. Stevie Silver badge

    Bah!

    An opportunity arises!

    I will market a Styrofoam "head" containing a simple sound chip with a looped sample burned in.

    The "ears" will be speakers.

    One simply places the headphones over the "head" and pressure-activated micro-switches turn the thing on, delivering unobtrusive-to-the-owner playback of "Hey Mickey" to the hackers, earworming them for their trouble.

    The device will be completely and utterly airgapped since it will never need an upgrade over the web. Should the hackers ever develop an immunity to "Hey Mickey" (all-but impossible), a mail-in card will cause a new proprietary chip to be sent out that can be substituted for the original. This new chip will contain the subscriber's choice of "Sugar Sugar", "Chirpy Chirpy Cheep Cheep" or "Love Grows Where My Rosemary Goes".

    Premium subscribers can access nuclear options like "Da Da Da", "Two Little Boys", or "I Was Born Under A Wandrin' Star".

    1. Swarthy
      Thumb Up

      Re: Bah!

      Thank you for listing the three "Nuclear Options" together. Just naming them is enough to trigger the earworm. Fortuitously, naming them together, in a group, makes them compete and they each cancel out the other two.

      Now I will be the bastard and point out the one you missed: MaNaMiNa

      1. Stevie Silver badge

        Re: Bah!

        If you are referring to "Ma-Na Ma-Na", it fails as an earworm by mentally conjuring up the version sung by Monster and the cow chorus, (accompanied by Zoot on sax) instead of the original.

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