Apple's T2 chip will prevent hackers from eavesdropping on your microphone • Hacker News Board

Re: Apple's T2 chip will prevent hackers from eavesdropping on your microphone

#21

Post by IBM » Sun, Nov 04, 2018, 10:10 PM UTC

imran3740 wrote: post #9

slededit wrote: post #5

Earlier quoted context omitted.

Who controls the switch? You need an entire secure system distinct from the untrusted CPU - or a manual switch on the side. The latter goes against everything Apple believes in design wise.

What about a physical killswitch goes against Apple's design? The iPhone has always had a ringer/vibrate switch on its side since it was introduced. Obviously it doesn't do anything hardware-wise, but it's still a switch that disables some functionality.

Almost all of Apple's security features are invisible and by default and don't get in the way. They're striking the balance between user experience and security.

Re: Apple's T2 chip will prevent hackers from eavesdropping on your microphone

#22

Post by JumpCrisscross » Sun, Nov 04, 2018, 10:13 PM UTC

davnicwil wrote: post #6

slededit wrote: post #5

Earlier quoted context omitted.

Who controls the switch? You need an entire secure system distinct from the untrusted CPU - or a manual switch on the side. The latter goes against everything Apple believes in design wise.

I'm suggesting the lid could control the switch, physically, as in when you close it the mic's circuit is broken.

> the lid could control the switch

Doing it on a chip sounds more reliable than adding a moving part.

Re: Apple's T2 chip will prevent hackers from eavesdropping on your microphone

#23

Post by caibkai » Sun, Nov 04, 2018, 10:19 PM UTC

Is there any other hardware running when the lid is closed?

Re: Apple's T2 chip will prevent hackers from eavesdropping on your microphone

#24

Post by GuB-42 » Sun, Nov 04, 2018, 10:19 PM UTC

davnicwil wrote: post #3

> The chip comes with a hardware microphone disconnect feature that physically cuts the device’s microphone from the rest of the hardware whenever the lid is closed Why do you need a chip for this? Can't you just break the circuit with a regular dumb physical switch? Or is this a much more complex problem than it first appears?

There is already a lid closed sensor. Adding another mechanical switch is more expensive, adds another point of failure, takes space, may interfere with the aesthetics, etc...

The T2 chip probably also acts as a controller for a lot of the builtin sensors, including the microphone and lid closed switch. As a result, adding a feature to turn off the microphone when the lid is closed becomes trivial. Basically just add a logic gate between the two.

Re: Apple's T2 chip will prevent hackers from eavesdropping on your microphone

#25

Post by jimhefferon » Sun, Nov 04, 2018, 10:20 PM UTC

Or they could do, you know, a simple $0.10 on-off slide switch.

Re: Apple's T2 chip will prevent hackers from eavesdropping on your microphone

#26

Post by newnewpdro » Sun, Nov 04, 2018, 10:20 PM UTC

notable_user wrote: post #4

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.

> 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.

Re: Apple's T2 chip will prevent hackers from eavesdropping on your microphone

#27

Post by BillinghamJ » Sun, Nov 04, 2018, 10:21 PM UTC

Details are here: https://www.apple.com/mac/docs/Apple_T2_Security_Chip_Overvi...

Re: Apple's T2 chip will prevent hackers from eavesdropping on your microphone

#28

Post by pessimizer » Sun, Nov 04, 2018, 10:22 PM UTC

cbluth wrote: post #2

Why is it so hard to believe the headline?

Because you know that the technology to physically disconnect a microphone when a lid is closed is extremely simple, and doesn't require a computer chip that is impossible for the user to audit.

Re: Apple's T2 chip will prevent hackers from eavesdropping on your microphone

#29

Post by lstodd » Sun, Nov 04, 2018, 10:26 PM UTC

542458 wrote: post #19

slededit wrote: post #10

Earlier quoted context omitted.

Yea that could work. I think this is cheaper for them surprisingly enough. Switches are expensive.

Expensive and failure-prone!

Just put a magnet-actuated switch into the mic itself and a magnet in the corresponding place in the body - problem solved.

Nothing to break, zero attack surface, what's not to like?

Re: Apple's T2 chip will prevent hackers from eavesdropping on your microphone

#30

Post by sschueller » Sun, Nov 04, 2018, 10:27 PM UTC

davnicwil wrote: post #3

> The chip comes with a hardware microphone disconnect feature that physically cuts the device’s microphone from the rest of the hardware whenever the lid is closed Why do you need a chip for this? Can't you just break the circuit with a regular dumb physical switch? Or is this a much more complex problem than it first appears?

Because a physical switch would actually provide security. /s

Any bug or future exploit negates this feature.

I have the feeling this was just done because it was possible and then the marketing team found out about it and decided to make a big deal out of it.