Comment by kestrel-robotic
21 hours ago
> the LED can't be controlled from software
If you look at tear downs apparently it is connected to the webcam so it is energized when the webcam receives power making it nearly impossible to defeat.
You can say a lot about Apple but the engineering is clever at the hardware level.
Also the Hall effect sensor disabling the mic when a MacBook lid is closed, apparently just about impossible to bypass. https://en.wikipedia.org/wiki/Hall_effect
It's not. I can place my iPhone next to my trackpad and the MacBook thinks I closed the lid.
That's not what people mean by 'bypassing', turning it off is obviously easy. The point is that activating the microphone while the lid is closed is pretty much impossible.
It's not even that clever, really. The camera power rail must be physically close to the camera, so it's trivial to hang an LED off it. A device manufacturer has to go out of their way to make it so the LED and camera function are independent, and I'm sure many do, for the worst reasons you can possibly think of.
It's more a testament to how little most companies care. The solution is simple and yet most products are defective.
For most products the LED is not a simple on/off indicator. It signals device state, user confirmations, ota updates, etc etc etc.
I’m at a loss for how you would signal all of that without a GPIO.
1 reply →
Nest cameras used to have a user toggle to enable/disable the camera LED; not the worst reason I can think of.
Yeah, and then came people hiding cameras in places where you clearly did not want a camera to be. Bathrooms in public areas, hotels, workplaces and AirBnBs are a much too common issue, it's like daily news some creep gets busted for running cameras.
2 replies →
It could be a typical design that the camera and LED always have power, and the LED is switchable.
Giving the camera plus LED a separate power supply means that the camera has to boot or come online, which maybe increases the dwell time. And the camera is not visible on the USB bus when powered off.
I think there's more engineering to Apple's design than it first seems.
The thing visible on the bus is the interface chip, not the sensor. Most cameras which I've seen hardwire their activity LEDs (it is impossible to grab stills or record video without lighting up the LED) do so by connecting the activity LED to the sensor power rail. With the sensor powered off, the device is still visible on the bus but you get no usable image data.
This still would allow one to "strobe" the power line making it impossible for a human to see the LED but the camera could still capture snapshots and at a decent framerate even.
Naw the LED stays on a little longer after you stop capturing image data. They either have burned in firmware or a simple circuit (RC and comparator) that stops your attack.