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"All Mac portables with the Apple T2 Security Chip feature a hardware disconnect that ensures that the microphone is disabled whenever the lid is closed." It's
by voctor 8y ago
"All Mac portables with the Apple T2 Security Chip feature a hardware disconnect that ensures that the microphone is disabled whenever the lid is closed."
It's interesting, I don't know if other brands do that?
- badwolf 8y agoVery interesting indeed.
- joshstrange 8y agoI wonder how that works for the Mac Mini. I'm honestly not sure if it even has a microphone built in or not.
- eddieroger 8y agoThe Mac Mini isn't a portable, so not at all?
- saagarjha 8y agoAFAIK it doesn't. You need to provide your own microphone.
- robotpony 8y agoPrevious gen didn't, so I doubt the new gen does.
- duxup 8y agoI wish we had a physical switch that cut power to the camera and mic... I worked on some old networking equipment a while back that had a physical fail over switch. If you opened the cover you could watch the connection switch, fun stuff. Also very effective.
- gh02t 8y agoThe description makes it sound like Apple is using a hardware interlock that I'd assume cuts power to the microphone via a MOSFET when the lid is closed. That's pretty much the same thing, just with a solid state switch instead of a mechanical contact.
- duxup 8y agoThat's pretty cool.
- therein 8y agoIt is pretty cool indeed, however keep in mind that's just standard component in circuits to turn signals on and off. It is just a PNP or NPN transistor. Everyone makes use of it.
- gh02t 8y agoTo be clear too, I'm just speculating about that part. The only thing this document says is that "This disconnect is implemented in hardware alone, and therefore prevents any software, even with root or kernel privileges in macOS, and even the software on the T2 chip, from engaging the microphone when the lid is closed." That implies to me that they are using some form of physical interlock (probably a magnet and Hall-effect sensor), and that they use this to completely disable the microphone. The most obvious way to me to do that in this case would be to cut the power with a transistor, but in principle there are a number of other ways it could be achieved.
- therein 8y agoI think it makes sense to assume they have a hall-effect sensor and a MOSFET but of course maybe they combined both in a single package. Thinking how a hall-effect sensor works, perhaps it would be possible to embed it in a wafer with some gates and you're done.
- DennisP 8y agoPurism laptops have hardware kill switches for camera/mic and wifi/bluetooth. https://puri.sm/products/librem-13/ https://puri.sm/products/librem-13/
- nobodyshere 8y agoUnfortunately it has much weaker specs. No thunderbolt, only dual core CPU, slow Wi-Fi. They didn't even care enough to tell us the screen resolution, which is at least to me an important thing to know before buying.
- ConceitedCode 8y agoNewer Thinkpads have a shutter to cover the camera, but mic still works when covered. https://www.businessinsider.com/lenovo-thinkshutter-laptops-webcam-covers-2018-1 https://www.businessinsider.com/lenovo-thinkshutter-laptops-...
- duxup 8y agoYeah I got some handy shutters from some conferences, not a bad solution.
- voctor 8y agoThey say that "The camera is not disconnected in hardware because its field of view is completely obstructed with the lid closed."
- kristofferR 8y agoAnd since the webcam in Macs electrically can't get power without also powering the green notification LED, it's impossible for malicious actors to activate the webcam silently while the lid is open.
- repolfx 8y agoIs that still true? I read some time ago that the LED used to be hardware controlled, but switched to being software controlled at some point.
- Johnny555 8y agoI wonder how long it will be until someone manages to figure out how to use image processing to read the noise seen by the camera sensor while the lid is closed and turn it into audio. Kind of like this: http://news.mit.edu/2014/algorithm-recovers-speech-from-vibrations-0804 http://news.mit.edu/2014/algorithm-recovers-speech-from-vibr...
- unwind 8y agoThat's certainly an interesting thought, but do note (from the linked article): In some of their experiments, the researchers used a high-speed camera that captured 2,000 to 6,000 frames per second.. I haven't checked, but I would be surprised if Apple uses cameras that are capable of that as normal user-facing webcams in their laptops ... Recovering meaningful audio signal (which usually has lots of data above 1 kHz) from the <100 Hz sampling done by a camera seems difficult, Nyquist and all, right?
- Johnny555 8y agoFrom the next paragraph: In other experiments, however, they used an ordinary digital camera. Because of a quirk in the design of most cameras’ sensors, the researchers were able to infer information about high-frequency vibrations even from video recorded at a standard 60 frames per second.
- duxup 8y agoDoes this mean you can't use it in a configuration with say one laptop, two external monitors, and lid closed... and still use the mic? I don't have a Mac so maybe that isn't a valid use anyway, but I do that with PCs all the time.
- rubatuga 8y agoIt is a valid use case, and no it seems like it won't work.
- duxup 8y agoTY, interesting. Granted, I get that for security ... can't be bending the rules or it would just be the method use to circumvent it.
- Wowfunhappy 8y agoAlso, since the mic would be covered by the lid, you probably wouldn't want to use it anyway under this scenario.
- dpkonofa 8y ago>seems like it won't work Are you speculating here or do you have some kind of insight?
- duxup 8y agoI think he is speculating, but any work around to bypass the rules related to the security chip would seem unlikely.
- rconti 8y agoOr maybe we're just reading it too literally and the document actually means "when the computer is asleep" but they said "when the lid is closed", thus creating the confusion? But I guess if it's about "sleep" mode, that's too easy to bypass in software without even attacking T2...
- nabla9 8y agoWhy you need security chip to ensure that?
- pwinnski 8y agoTo prevent nefarious software from listening in unknown to you.
- nabla9 8y agoWhy it needs to go trough security chip? Laptop closed -> microphone cut off does not need complex logic. It's just simple switch.
- Wowfunhappy 8y agoI don't think you do, it's just an additional security feature that they put in the T2 PDF for some reason.
- dsfyu404ed 8y agoBecause if you don't mention that you've got a hardware switch covering the mic someone will ask you why your security chip has this glaringly obvious hole in it.
- PascLeRasc 8y ago
- byproxy 8y agoI wonder what determines whether or not the lid is closed.