Hacker News Board Hacker News, browsed like a classic message board
Live data from Hacker News

Malware can turn off webcam LED and record video, demonstrated on ThinkPad X230

github.com

Post reply on HN
Print view View original

301–310 of 554 posts

Re: Malware can turn off webcam LED and record video, demonstrated on ThinkPad X230

#301

Post by whartung »

tehjoker wrote: post #270
II2II wrote: post #262

Earlier quoted context omitted.

> and no firmware is involved in enforcing the LED stay on for 3 seconds after a single frame is captured. I may be the oddball here, but that 3 second duration does not comfort me. The only time I would notice it is if I am sitting in front of the computer. While someone snapping a photo of me while working is disconcerting, it is not the end of the world. Someone snapping photos while I am away from the screen is m…

It's strange that none of these companies will include a closable cover for the camera. I got one aftermarket. It is very reassuring since no hacking or accidental misclicks on my part can move the cover.

I have a sticky piece of post it note more or less permanently affixed over my camera.

Re: Malware can turn off webcam LED and record video, demonstrated on ThinkPad X230

#302

Post by axoltl »

KennyBlanken wrote: post #279
axoltl wrote: post #163

Earlier quoted context omitted.

I happen to have some first-hand knowledge around the subject! In 2014 someone did a talk[0] on disabling the camera on some older Macbooks. It was fairly trivial, basically just reflashing the firmware that controlled the LED. I worked on the security team at Apple at the time and in response to this I attempted to do the same for more modern Macbooks. I won't go into the results but the decision was made to re-arch…

I've seen a million people parroting "oh now apple fixed it!" and not a single person who has actually verified/proved it. Go on, show my any third party security researcher who has verified this claim via examining the actual hardware. You'll pardon us all if we don't really believe you, because a)there's no way for any of us to verify this and b)Apple lied about it before, claiming the LED was hard-wired in blah bl…

I'd love for a third party to verify the claim! I'm just giving you an overview of the work that went into making this a thing, knowing full well you have absolutely no reason to trust me.

The LED being "hard-wired" is a tricky statement to make, and I actually wasn't aware Apple has publicly ever made a statement to that effect. What I can say is that relying on the dedicated LED or "sensor array active" signal some camera sensors provide, while technically hard-wired in the sense there is no firmware driving it, is not foolproof.

Re: Malware can turn off webcam LED and record video, demonstrated on ThinkPad X230

#303

Post by axoltl »

jorvi wrote: post #264
axoltl wrote: post #163

Earlier quoted context omitted.

I happen to have some first-hand knowledge around the subject! In 2014 someone did a talk[0] on disabling the camera on some older Macbooks. It was fairly trivial, basically just reflashing the firmware that controlled the LED. I worked on the security team at Apple at the time and in response to this I attempted to do the same for more modern Macbooks. I won't go into the results but the decision was made to re-arch…

I assume you're not longer working on it, but why not just wire it so that: - The LED is in parallel, but with the sensor voltage supply, not the chip - Camera sensor idle voltage = low voltage for the LED (be it with stepping if needed) - Camera sensor active voltage = high voltage for the LED (again, stepping if needed) - little capacitor that holds enough charge to run the LED for ~3 seconds after camera goes back…

That's basically how this works, but manufacturing electronics at a massive scale requires some more flexibility. For example, capacitors have a pretty large tolerance (sometimes +/- 20%) and LEDs have quite a bit of variety in what voltages they'll work at. So for some people the LEDs might last 3 seconds, for some they might last 5s. Using a capacitor also means the LEDs will fade slowly instead of just turning off sharply.

If the LEDs come from a different supplier one day, who is going to make sure they're still within the spec for staying on for 3 seconds?

(And yes, I have long since parted ways with Apple)

Edit:

And to add on: That capacitor needs time to charge so now the LED doesn't actually come on when the sensor comes on, it's slightly delayed!

Re: Malware can turn off webcam LED and record video, demonstrated on ThinkPad X230

#305

Post by nine_k »

542458 wrote: post #51
sbarre wrote: post #3

I thought the whole point of these camera LEDs was to have them wired to/through the power to the camera, so they are always on when the camera is getting power, no matter what. Having the LED control exposed through the firmware completely defeats this.

They are hardwired on Macbooks. From Daring Fireball, quoting an email from an Apple engineer. > All cameras after [2008] were different: The hardware team tied the LED to a hardware signal from the sensor: If the (I believe) vertical sync was active, the LED would light up. There is NO firmware control to disable/enable the LED. The actual firmware is indeed flashable, but the part is not a generic part and there ar…

That's backwards.

The LED should be connected to camera's power, or maybe camera's "enable" signal. It should not be operable via any firmware in any way.

The led also has to be connected through a one-shot trigger (a transistor + a capacitor) so that it would light up, say, for at least 500 ms no matter how short the input pulse is. This would prevent making single shots hard to notice.

Doing that, of course, would incur a few cents more in BOM, and quite a bit more in being paranoid, well, I mean, customer-centric.

Re: Malware can turn off webcam LED and record video, demonstrated on ThinkPad X230

#306

Post by Nursie »

ohhnoodont wrote: post #297
Nursie wrote: post #253

Earlier quoted context omitted.

Depends what your threat model is? Nobody but Abby and Ben care if Ben is caught admitting he cheated on Abby. But naked images of Abby can head off into the ether and be propagated more or less forever, turn up on hate sites, be detrimental to careers etc. If your threat model is leaking company secrets then sure, microphone bad, as is anything having access to any hardware on your machine. So sure, maybe people oug…

My point is that the threat model is backwards. The threat associated with a camera is the least severe compared to anything else a malicious person could do with access to your computer. Recored conversations, chats and email, browsing history, etc are all much more likely to result in harm if leaked than a recording of you innocently in your home. > Nobody but Abby and Ben care if Ben is caught admitting he cheated…

I don't think it is backwards, personally. The threat of public humiliation, and the capability for someone to spy on what you do in your own home, is worse with the camera.

> chats and email, browsing history, etc are all much more likely to result in harm if leaked than a recording of you innocently in your home.

This is far less of an intrusion for most people than recording what they are actually doing in their own home IRL. People know that information can be hacked, they don't expect and react quite differently to someone actually watching them.

> That destroys families, standing within a community, and very often careers.

Yes, but it doesn't stay on the internet forever in quite the same way.

Now I get to some extent what you're saying - aren't the consequences potentially worse from other forms of information leak?

Maybe. It depends on how you weight those consequences. I'd put (for example) financial loss due to fraud enabled by hacking my accounts as far less important than someone spying on me in my own home. Even if they didn't use that to then extort me, and were using the footage for ... uh ... personal enjoyment. I think a lot of people will feel the same way. The material consequences might be lesser, but the psychological ones not so much. Not everything is valued in dollars.

Re: Malware can turn off webcam LED and record video, demonstrated on ThinkPad X230

#307

Post by nrp »

netsharc wrote: post #161
nox101 wrote: post #118

Earlier quoted context omitted.

I suspect most people don't want it. I can imagine lots of people calling customer service "Q: why doesn't my camera work?", "A: Did you open the cover?" There's just a valid an argument to do the same for phones. How many phones ship with camera covers and how many users want them? You can get a stick on camera cover for $5 or less if you want one. I have them on my laptops but not on my phone. They came in packs of…

> I can imagine lots of people calling customer service "Q: why doesn't my camera work?", "A: Did you open the cover?" In some over-engineered world, when the camera cover is engaged the webcam video feed would be replaced by an image of the text "Slide camera cover open" (in the user's language) and an animation showing the user how to do so.

We have that on the most recent generation of Framework Laptop. When the hardware privacy switch is engaged, the image sensor is electrically powered off and the camera controller feeds a dummy frame with an illustration of the switch.

Re: Malware can turn off webcam LED and record video, demonstrated on ThinkPad X230

#308

Post by DaiPlusPlus »

WiSaGaN wrote: post #238
sbarre wrote: post #3

I thought the whole point of these camera LEDs was to have them wired to/through the power to the camera, so they are always on when the camera is getting power, no matter what. Having the LED control exposed through the firmware completely defeats this.

That's why many ThinkPads have physical covers over their cameras. You don't even need to worry about whether the LEDs are hardwired - relying on any electronic indicator is already a half-baked security measure. If you want real security, just go with a physical solution.

…until it isn’t: my ThinkPad P1 Gen 6 has the camera cover, yes - but it doesn’t have a cover for the depth-sensing camera, only the RGB cam, even though userland applications can get imaging data from that camera just as easily - which is potentially a bigger security issue: I imagine you could reconstruct my facial shape from the data and build a dummy head to get into my iPhone/iPad via FaceID.

(No, I’m not actually worried about this, I’m far too unimportant for anyone to make a targeted attack against)

Re: Malware can turn off webcam LED and record video, demonstrated on ThinkPad X230

#309

Post by cozzyd »

tehjoker wrote: post #270
II2II wrote: post #262

Earlier quoted context omitted.

> and no firmware is involved in enforcing the LED stay on for 3 seconds after a single frame is captured. I may be the oddball here, but that 3 second duration does not comfort me. The only time I would notice it is if I am sitting in front of the computer. While someone snapping a photo of me while working is disconcerting, it is not the end of the world. Someone snapping photos while I am away from the screen is m…

It's strange that none of these companies will include a closable cover for the camera. I got one aftermarket. It is very reassuring since no hacking or accidental misclicks on my part can move the cover.

My Thinkpad does.

Re: Malware can turn off webcam LED and record video, demonstrated on ThinkPad X230

#310

Post by ohhnoodont »

Nursie wrote: post #306
ohhnoodont wrote: post #297

Earlier quoted context omitted.

My point is that the threat model is backwards. The threat associated with a camera is the least severe compared to anything else a malicious person could do with access to your computer. Recored conversations, chats and email, browsing history, etc are all much more likely to result in harm if leaked than a recording of you innocently in your home. > Nobody but Abby and Ben care if Ben is caught admitting he cheated…

I don't think it is backwards, personally. The threat of public humiliation, and the capability for someone to spy on what you do in your own home, is worse with the camera. > chats and email, browsing history, etc are all much more likely to result in harm if leaked than a recording of you innocently in your home. This is far less of an intrusion for most people than recording what they are actually doing in their o…

I think we may just be bumping into cultural differences here. I grew up in a household were being naked around family members was common. I spend time in clothing-optional spaces. I rarely draw the blinds on my windows, etc. I'm not concerned with what other people think in this way and such images could never be used to extort me. Consider the case of Germany - people there are extremely concerned about their privacy and data protection. At the same time public nudity is an entrenched cultural norm.

It's also known that people are not very good at assessing risk. People are more word about dying at the hands of a serial killer than they are of dying in a car crash or slipping in the shower. I feel you're underplaying the psychological harm of having all of your data crawled through by a creep (that would include all of your photos, sites visited, messages sent, everything).

All I can really say is that if someone gained access to my machine, the camera would be the least of my concerns. That's true in nearly every context (psychological, financial, physical, etc).

Post reply on HN