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Comment by masklinn | Hacker News Reader

> My laptop has a microphone and video. Surely Microsoft could just start recording with the with right windows update?

It's a commonly mentioned issue, and a somewhat regular occurrence with various malware or "security solutions".

That's why a number of laptops have either visual indicators or shutters (though mostly for the cameras, sadly hot mics are rarely a consideration), and a rare few have physical disconnection switches (again mostly for cameras).

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Macbooks since 2018 physically disable microphones and webcams when the lid is closed: https://www.businessinsider.com/apple-macbook-air-and-2018-m...

How does a chip "physically disconnects" a device?

Presumably power is disconnected by the T2 chip. Different from mechanical disconnect via a physical switch, but equivalently effective if you trust the T2 chip. (And if you don’t ... well, you can’t use the MacBook securely at all.)

You had better not trust the T2 chip, because it is vulnerable to the checkm8 exploit and the checkra1n folks have already demonstrated total compromise. The encryption functionality isn't affected if you have FileVault on, because your password is not stored anywhere on the device, but everything else, from basic SMC functions like mic/cam/fans/touchbar to secure boot to verifying the microcode and ME firmware before loading are totally useless now.

AFAIK, the T2 is always powered on even when the main CPU is off, so this could have ultra-long-term persistence.

Reference?

https://www.idownloadblog.com/2020/03/10/luca-todesco-teases...

Because the mic and camera runs through said chip.

But the lid is open for several hours a day while I'm working!

That would be a big reason to get a MacBook for the first time ever.

Perhaps within the hazy, inextricable mists of jack, pulse and alsa, there's an answer. I remember feeling qualified for a job at NSA after getting midi and my mic to work (effectively) on my Arch (Mint, Ubuntu, Debian, etc) laptops years ago. It was a feat. I can see:

Hacker1: we've got root.

Hacker2: yeah, but how the fuck do we get audio to work?

Hacker1: modify grub to default to windows partition and reboot, or maybe install Virtual Box and run windows. Probably not possible otherwise.

Hacker2: No, waaay too slow, they're on an ATT gateway. Find a softer target.

I saw one gizmo for mic the other day

https://shop.googlemerchandisestore.com/Google+Redesign/Acce...

haven't tried it though, anyone has any experience? Does it really muffle the sound enough?

I think the idea there is that it physically disconnects the mic, since the laptop instead tries to use the headphone mic (which in this case isn't connected). Not sure if it would actually work, it would be easy to 3d-print one to test.

If you connect a plug to the audio jack, sure, the laptop probably defaults to using that jack for input and output. But you can still choose to use the built-in mic, right? So it's not physically disconnecting anything, just triggering a software disconnect.

AFAIK you're correct. Though it's possible most spying software just uses the default mic and doesn't have the capabilities to switch the input device?

Not a Mac user, and the last time I played with sound stuff in nix was almost 15 years ago...

But I feel like switching input (or even collecting multiple sound inputs) on a nix OS is not much more convoluted than dealing with the sound stack in general. But that's probably also related to how the driver itself interfaces with the audio device...

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