8 ms·

This only protects when the lid is closed, but many people leave the lid open on their desk. I would love to see a light come on if the camera or microphone is

This only protects when the lid is closed, but many people leave the lid open on their desk. I would love to see a light come on if the camera or microphone is receiving power, and then only turn on power to these devices when a program requests it.

newnewpdro 8y ago
> I would love to see a light come on if the camera or microphone is receiving power, and then only turn on power to these devices when a program requests it. Isn't the microphone a simple passive device no different than a voice coil in a magnetic field? I don't think it's that simple, since it won't be powered. My understanding is that there's often a reconfigurable circuit in the sound chip which determines where the lines in and out are routed. So even if you've physically disconnected the microphone, but left internal speakers connected, it's possible to turn the speakers into a microphone via software alone.
- bigiain 8y ago
  There's at least a pre amp and a d/a converter that the mic needs to have powered up and running before any of it's signal can be used by the rest of the computer.
  - newnewpdro 8y ago
    Which will all be inside an IC, away from the microphone. So what, does the light turn on whenever the entire IC sees power? Because if it relies on a signal from within the software-controlled IC, that's not exactly trivial to audit.
    - XMPPwocky 8y ago
      The trivial solution would be a LED + resistor just wired across the mic's power rails.
      - newnewpdro 8y ago
        When the microphone is a passive connected to a multifunction IC there's no such power rail.
        justtopost 8y ago
        Most laptop mics are condenser electret mics which usually use a small dc current, although not always.
        newnewpdro 8y ago
        Not the last time I went down this road hardening a Thinkpad, see Step 6 at [1] (not my site). I haven't bothered with any smartphones yet, so I can't speak to what they tend to use for a mic. But if I carried one I'd definitely rip out all the voice coils and rely on a pair of headphones w/integrated mic for voice comms to mitigate potential for eavesdropping. [1] https://blog.patternsinthevoid.net/replacing-a-thinkpad-x60-bootflash-chip.html https://blog.patternsinthevoid.net/replacing-a-thinkpad-x60-...
        colejohnson66 8y ago
        When replacing the lightning assembly on my iPhone 6, I noticed that the microphone looks passive. Here’s a photo[0]; It’s the little bronze(?) square next to the headphone jack. [0]: https://www.ifixit.com/Store/iPhone/iPhone-6-Lightning-Connector-and-Headphone-Jack/IF268-004-1 https://www.ifixit.com/Store/iPhone/iPhone-6-Lightning-Conne...
dpkonofa 8y ago
The camera already functions this way. The light is connected to the actual power of the camera and cannot be disabled unless the camera is also disabled. The microphone, to my knowledge, doesn't function like this but I don't think it makes sense for it to function like this as the microphone doesn't really need power outside of what's provided to the amps and DACs inside the machine. It would be too easy to work around. Any membrane capable of vibration would be able to be used as a microphone, including the laptop's speakers, so it'd be more work for little gain.
- snacktaster 8y ago
  > The light is connected to the actual power of the camera and cannot be disabled unless the camera is also disabled. This was proven false when malware was discovered that accessed the camera on Mac laptops without activating the LED light. It's mentioned in the article.
  - alphabettsy 8y ago
    The reasearch to prove that vulnerability was done on Macs made up until 2008 if I’m not mistaken. It’s not clear if that attack is still possible.
    - enos 8y ago
      Which Macs still have a light?
      - macintux 8y ago
        I believe they all do, but I haven’t been able to find a document to confirm that.
  - isostatic 8y ago
    Am I the only one who has tape over my laptop camera? (Specifically a peppa pig sticker)

newnewpdro 8y ago

> I would love to see a light come on if the camera or microphone is receiving power, and then only turn on power to these devices when a program requests it. Isn't the microphone a simple passive device no different than a voice coil in a magnetic field? I don't think it's that simple, since it won't be powered. My understanding is that there's often a reconfigurable circuit in the sound chip which determines where the lines in and out are routed. So even if you've physically disconnected the microphone, but left internal speakers connected, it's possible to turn the speakers into a microphone via software alone.

bigiain 8y ago
There's at least a pre amp and a d/a converter that the mic needs to have powered up and running before any of it's signal can be used by the rest of the computer.
- newnewpdro 8y ago
  Which will all be inside an IC, away from the microphone. So what, does the light turn on whenever the entire IC sees power? Because if it relies on a signal from within the software-controlled IC, that's not exactly trivial to audit.
  - XMPPwocky 8y ago
    The trivial solution would be a LED + resistor just wired across the mic's power rails.
    - newnewpdro 8y ago
      When the microphone is a passive connected to a multifunction IC there's no such power rail.
      - justtopost 8y ago
        Most laptop mics are condenser electret mics which usually use a small dc current, although not always.
        newnewpdro 8y ago
        Not the last time I went down this road hardening a Thinkpad, see Step 6 at [1] (not my site). I haven't bothered with any smartphones yet, so I can't speak to what they tend to use for a mic. But if I carried one I'd definitely rip out all the voice coils and rely on a pair of headphones w/integrated mic for voice comms to mitigate potential for eavesdropping. [1] https://blog.patternsinthevoid.net/replacing-a-thinkpad-x60-bootflash-chip.html https://blog.patternsinthevoid.net/replacing-a-thinkpad-x60-...
        colejohnson66 8y ago
        When replacing the lightning assembly on my iPhone 6, I noticed that the microphone looks passive. Here’s a photo[0]; It’s the little bronze(?) square next to the headphone jack. [0]: https://www.ifixit.com/Store/iPhone/iPhone-6-Lightning-Connector-and-Headphone-Jack/IF268-004-1 https://www.ifixit.com/Store/iPhone/iPhone-6-Lightning-Conne...

dpkonofa 8y ago

The camera already functions this way. The light is connected to the actual power of the camera and cannot be disabled unless the camera is also disabled. The microphone, to my knowledge, doesn't function like this but I don't think it makes sense for it to function like this as the microphone doesn't really need power outside of what's provided to the amps and DACs inside the machine. It would be too easy to work around. Any membrane capable of vibration would be able to be used as a microphone, including the laptop's speakers, so it'd be more work for little gain.

snacktaster 8y ago
> The light is connected to the actual power of the camera and cannot be disabled unless the camera is also disabled. This was proven false when malware was discovered that accessed the camera on Mac laptops without activating the LED light. It's mentioned in the article.
- alphabettsy 8y ago
  The reasearch to prove that vulnerability was done on Macs made up until 2008 if I’m not mistaken. It’s not clear if that attack is still possible.
  - enos 8y ago
    Which Macs still have a light?
    - macintux 8y ago
      I believe they all do, but I haven’t been able to find a document to confirm that.
- isostatic 8y ago
  Am I the only one who has tape over my laptop camera? (Specifically a peppa pig sticker)