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It is a known fact that your laptop camera can be hacked to spy on you. While the most often mentioned remedy is very low tech yet effective, everyone seems to omit the fact that the microphone can be used to spy on you too. I have no proof but it seems probable.

Is there any remedy to this except for the general "making sure your laptop is not hacked"?

EDIT: "reversible block" is the word I was looking for!

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Wouldn't stop problems when you actually wanted to use the device microphone, but softpatching a talk radio station in to the mic input would be quite fun, especially if you knew someone was listening. Adding a bit of gain to make the signal clip a bit too would add to the fun. –  Owen Dec 19 '13 at 15:13
    
I disagree with the premise. It is a known fact that once you have been hacked, your webcam can be used to spy on you. But it is by no means certain that you can be hacked in the first place. –  Matt Dec 21 '13 at 18:49

1 Answer 1

If your laptop is "hacked" then everything you do on the laptop can be known to the attacker. Yes, the microphone can be used to listen to the environment sounds and there is no ambiguity about it; the debate on Webcams is because Webcams often come with a LED which supposedly turns on whenever the Webcam is "looking", and the question is whether it is possible to activate the Webcam without turning that LED on. Microphones never had such a LED to begin with, so there is no question about that: whatever controls the computer can "listen" at will.

The same can be said of your cell phone or of any system which runs software and physically contains a microphone (so this also applies to most "land-line phones").

Low-tech solutions have the nice side of being obviously right, meaning that you can, as a human user, check that they are in force, without having to trust that the machine was not compromised as some software level. The trouble with microphones, though, is that while deactivating them permanently is easy (if only by wrenching the microphone out with a pair of pliers), a reversible block is hard. One possibility is to physically disable the internal microphone, and plug an external microphone in the relevant plug whenever you actually want to record sound.

Apart from that, a machine compromise is already quite pervasive: if hostile entities can activate your laptop microphone without your consent, then it can be argued that you already have bigger problems, namely that all your emails, documents, network activity, passwords... are known to the attacker.

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"reversible block" is the word I was looking for! –  daniel.sedlacek Dec 19 '13 at 15:21

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