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"These new Dell privacy buttons are basically hardware kill switches for the microphone and web camera video stream. The Dell privacy driver sent out on Tuesday
by devenblake 6y ago
"These new Dell privacy buttons are basically hardware kill switches for the microphone and web camera video stream. The Dell privacy driver sent out on Tuesday for the Linux kernel is about manipulating the relevant LEDs and tracking the status of the hardware-based controls where as the actual toggling of the audio/video support is handled by the hardware."
Why not just wire the LEDs up to the same power line that goes to the camera?
- surround 6y agoThat seems to be an issue with most webcams - the indicator light itself can be compromised and disabled.
- mnahkies 6y agoI remember having a usb Logitech webcam that included disabling the indicator as a first class option in their control panel - not a big leap to imagine malware doing it
- LeonM 6y agoThird party webcams, yes. Basically any modern laptop with a build-in webcam has a hardware controlled LED, not software controlled.
- m463 6y agoI don't see that this is necessarily true or easy to figure out.
- discreditable 6y agoThey may be wired to the power line. I think the goal is more to give the kernel some way to know the mic/camera is explicitly disabled and not disconnected/missing/broken.
- varispeed 6y agoWouldn't that tell any spy device / software that the subject has switched off the means he or she can be surveiled by? I cannot see how this could help with anything. They should rather do a physical switch that would 0 the data lines from these devices, so that camera or the microphone would be seen as working, but not sending any signal. Even better if you could pre-program some kind of ambience sound and pre-recorded cam video, so that once you turn it off, the perpetrator will think that they are still getting something.
- antoinealb 6y agoIt might be for usability reasons: having your video conferencing application tell you "Your webcam appears to be disabled by the privacy switch, is that intentional?" probably saves a lot of time in tech support calls.
- lultimouomo 6y agoAlso, having your video conferencing application send some prerecorded audio and video data to your colleagues because you inadvertently turned the kill switch would not be a highly desirable outcome.
- crote 6y agoWhy would you care about fooling surveillance? The goal is to prevent a potential adversary from getting any video/audio footage, them being aware of you actively blocking any attempts is not really relevant. Besides, the vast majority of users will not be under active attack. Having an on-screen popup when you try to use the webcam telling you that it has been hardware-disabled is quite a must-have. If you don't have something like this, you'll get a lot of support calls which boil down to "you accidentally pressed the kill switch, press it again to re-enable".
- jakobdabo 6y ago> Why would you care about fooling surveillance? For example, when you are "required" [1] to run surveillance software on your computer. [1] https://www.vice.com/en/article/n7wxvd/students-are-rebelling-against-eye-tracking-exam-surveillance-tools https://www.vice.com/en/article/n7wxvd/students-are-rebellin...
- absolutelyrad 6y ago> Why not just wire the LEDs up to the same power line that goes to the camera? You know why.
- yjftsjthsd-h 6y agoLovely; care to enlighten the rest of us?
- hedora 6y agoIt’s a rhetorical question. There’s no good reason not to do it. The main reason is cost and hardware complexity, which would be negligible if the camera asic simply had an “I am on” pin to drive an LED. Laptop manufacturers clearly don’t care about this issue enough to insist that camera and audio hardware manufacturers include such a pin on future models.
- deleted 6y ago[deleted]
- mastax 6y ago> Why not just wire the LEDs up to the same power line that goes to the camera? It's just difficult enough to not bother considering the market doesn't care. Webcams are typically USB 2.0 devices using generic drivers from the operating system or manufacturer. It's easy from a hardware and software perspective to send a command to the webcam to disable itself and turn off its LED. If you want to completely cut power then you need to add power switching circuitry. You could use one of your CPU's limited GPIO pins to control the switching but now you probably need a smart power switch (~$0.30, which is significant) since the low voltage (1.2V?) GPIO can't handle switching a regular mosfet gate. GPIO writes are usually easy (just write to a memory address), but you'd still need to modify the vendor driver to do this and then distribute the driver. Motherboards typically have embedded controllers which have GPIO - on desktops there is a SuperIO chip, I believe laptops typically use a regular microcontroller. Now you have some 3.3V GPIOs that can handle gate switching so you can use a regular MOSFET (~$0.10). You still need to modify and distribute the webcam driver, and now it might have to communicate with another driver which is handling the embedded controller. Now you have to deal with the webcam disconnecting and reconnecting as you switch power to it. You want the device to always be present even if it's not enumerating on the USB bus, so you can select the webcam in zoom and turn it on and so you're not constantly playing the hardware connect/disconnect sound - even more driver changes. Maybe the webcam takes significantly longer to turn on now because it has to boot and enumerate. That was all somewhat informed speculation, but I think it illustrates how a seemingly simple thing gets complicated. The electronics industry could easily solve these issues if there was motivation, but there just isn't. Edit: Well, I'm posting this on an article talking about a vendor which is doing the work to make this happen. I guess I should say there's just enough motivation to eventually get around to solving this problem in a mature market.
- m463 6y agoFalse. The market does care. People want: hardware kill switches. They want to cut their camera. (I've seen tape many times) They want to mute their microphone for real. Even non-nefarious "on-screen" mute buttons are subject to abuse. For instance, in webex the conference host can unmute one or all of other people's mute buttons remotely. (To be clear there is a use case for this) I wonder how many apps are listening even while mute is on. I would expect many of them. and then there are exploits, which are lower probability but can do much more damage.
- colejohnson66 6y agoA “kill switch” is more preferable because it prevents an attack, whereas wiring the LED to the power line only notifies you when you’ve been attacked; by then it’s too late; you’ve already been compromised.
- ArnoVW 6y agoPerhaps because all it takes is 1/24th of a second to make a picture? Or because once the light is on, it's too late? Or because I don't want to risk missing the light being on, just because the computer is on but I m not behind it?
- sschueller 6y agoSo the NSA/CIA/FBI can enable the camera/mic without you knowing.
- Kuinox 6y agoI remember a hack were basically if you just light up the camera, take a pic, and power off it, the led don't have enough time to emit light.
- hda2 6y agoEven if the LED remained on, the victim would be powerless to do anything about the picture that was taken. I've seen videos on youtube of scammers doing this to blackmail their victims. Kill switches should be mechanical and should physically disconnect the device from the system. Kill switches and lights that are controllable by software will be exploited.
- Kuinox 6y agoI know, was just showing that LED wired on power is not enough.
- dastx 6y agoIt would be super nice for manufacturers to start doing that, but this is not a silver bullet. There's been so many times where I've just had my laptop stay open and on for different reasons. If in such scenarios the webcam comes on, the likelihood of me seeing the camera light on is quite low. I'm sure I'm not the only person either. Hardware switch is still the best solution. My lenovo laptop has basically a builtin webcam cover, and I absolutely love it.