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Headphones can be hijacked to surreptitiously record audio

wired.com

101–110 of 158 posts

Re: Headphones can be hijacked to surreptitiously record audio

#101
post #53

Earlier quoted context omitted.

Or USB amps for that matter.

If the USB amp uses the same RealTek chip, then good luck with trusting it.

If it is constructed just that there is an amplifier after what is supposed to be the output channel, you would probably be fine even if it was the the RealTek chip. There isn't going to be much coupling between a signal input to the output of the amplifier going back to the input as an output.

Re: Headphones can be hijacked to surreptitiously record audio

#102
post #64

"Great. Now Even Your Headphones Can Spy on You" Ironic coming from Wired, one of the most ad/tracker infested sites you could visit.

And a big difference is that you know ad trackers on Wired spy on you, while headphones... eh, unlikely in practice.

Re: Headphones can be hijacked to surreptitiously record audio

#103

Serious question: I understand the argument against the classic "why should I care if someone records my conversations? I don't do anything illegal.", being that once the government starts recording everything you say the freedom of being able to say anything negative against them goes away knowing they could be listening. That said, why should I, a boring law abiding citizen, go around disabling my hardware and cove…

There's probably no reason for you to go around disabling hardware etc. You're aware enough of the implications and risks, it's possible you'll get pwned but not too likely. (Honestly I'm more personally worried about the inconvenience of Google nuking my gmail for no reason than anything the NSA might be up to.) Some of my coworkers cover up their work laptop webcams by default. I don't, the realistic threat model is IT or some other company representative spying on me, and I don't really care about that. If I find out I'll quit and I'm sure there will be lawsuits anyway.

All that said, I never liked the "well one day the government will accuse you of a crime somehow or otherwise severely limit your speech" argument. To me the better counter-argument is: "Fine, you don't care at all, you don't have to care. Similarly some people are super paranoid and live in a faraday cage etc., they can do that all they want. But a lot of people care to some degree in between, and a lot of other people are uneducated or unaware of the actual risks so aren't even aware of the problem that they could decide to care/not care about. If you don't care at all, again that's fine, just get out of our way as we try to protect people by default. Mass education of every issue is infeasible."

Re: Headphones can be hijacked to surreptitiously record audio

#105
post #83

Here's a neat party trick for you. I had a MacGyver moment in the past where I made a phone call with only are pair of old earbuds and a phone cord (no switches, no dial pad). A speaker is basically the same thing as a microphone in reverse. Normally it takes an electrical signal to move a physical element that creates the sound waves. But you can also move the element and it will generate an electrical signal. To di…

Welcome Kevin Mitnick!

Re: Headphones can be hijacked to surreptitiously record audio

#106
post #40

Would be cool if Purism or similar companies had a nice big hardware switch that controlled access to any recording equipment.

A camera/mic switch should be required by law on every laptop and phone. Please don tell me a 5c switch is too expensive for a $300 phone.

The cost lies in replacing the 300$ phones where the switch breaks (earlier than expected).

Cameras are easier, blocking light is even more low-tech than closing a circuit. Unfortunately, cameras are already the limiting component in the current craze for ever thinner devices, so adding a slider on top would not be very popular. Theoretically, cameras could also be physically disabled by shifting some elements that are already there out of the optical axis. The precision requirements to reliably restore it to working condition would be insane.

Re: Headphones can be hijacked to surreptitiously record audio

#107

Earlier quoted context omitted.

That bar seems a lot lower in the last few weeks.

Constitutional amdendments require ratification by 3/4 of states. 20/50 states voted for Clinton. That is still quite a high bar.

I think the era of amendments has passed. Very unlikely we see a new one anytime soon.

Amendment XXVI, 18-year-olds can vote, ratified in 1972. Amendment XXVII, left over from 1789, relates to Congressional pay increases, ratified in 1992.

I didn't even know about the last one (I assume I can trust Wikipedia about it)? Which means the last "real" amendment was 44 years ago. None of the currently unratified amendments seem at all close to reaching the required number of ratification votes.

Re: Headphones can be hijacked to surreptitiously record audio

#109
post #83

Here's a neat party trick for you. I had a MacGyver moment in the past where I made a phone call with only are pair of old earbuds and a phone cord (no switches, no dial pad). A speaker is basically the same thing as a microphone in reverse. Normally it takes an electrical signal to move a physical element that creates the sound waves. But you can also move the element and it will generate an electrical signal. To di…

I've used this before in a pinch too, speaker as a microphone in reverse. that got me wondering... would it be possible to use the same principle with another type of listening device. Focusing a laser beam on a window allows you to hear a conversation in the room. so could the same principle be applied and allow a laser beam to transmit audio?

Re: Headphones can be hijacked to surreptitiously record audio

#110
post #76

Earlier quoted context omitted.

It seems like something that would work for built-in speakers too. They're driven by the same audio codec chips (eg realtek), but wired directly instead of through an external socket.

I think the opposite. Speakers are driven by an amplifier that will not let the audio in reverse, even if the soundcard output was switched to act as an input.

But might there be sufficient coupling between the amplifier's output and its input, such that driving the output pins via speaking into the speaker can produce a voltage on what is usually the input line to the amplifier?

I suspect it may be possible, depending on what the firmware allows - amplifier circuitry often utilizes feedback in some form or another, which is essentially coupling the output to the input. And even if the amplifier is powered off, there's bound to be capacitive coupling between the input/output lines, but that's probably too small to be useful.

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