Pixnapping Attack
14 comments
·October 15, 2025bilekas
It's not exactly a new technique but it's effective for most super targeted attacks, honestly it seems if you were this inclined to be able to get a specific app on the users phone, you might as well just work off the Android app you've already gotten delivered to the users phone. Like Facebook.
Throw a privacy notice to the users "This app will take periodic screenshots of your phone" You'd be amazed how many people will accept it.
> Did you release the source code of Pixnapping? We will release the source code at this link once patches become available: https://github.com/TAC-UCB/pixnapping
It's not exactly impossible to reverse what's happening here. You could have waited until it was patched but sounds like you wanted to get your own attention as soon as possible.
ChrisMarshallNY
Huh. I don’t know that I’ve seen a whole domain name registered, for a paper on a single CVE, before.
w4yai
It's quite standard for "big" CVEs nowadays
esher
I was looking for a nice browser game, just judging by the name.
ggm
Not a phone designer, but could we imagine a new class of screen region which is excluded from screen grab, draw over and soft focus with a mask, and then notification which do otp or pin subscribe to use it?
charcircuit
App developers can already dynamically mark their windows as secure which should prevent any other app from reading the pixels it rendered. The compositor composites all windows, including secure windows and applies any effects like blur. No apps are supposed to be able to see this final composited image, but this attack uses a side channel they found that allows apps on the system to learn information about the pixels within the final composition.
ZiiS
The attack needs you to be able to alter the blur of pixels in a secure window; this could be forbidden. A secure window should draw 100% as requested or not at all.
charcircuit
The blur happens in the compositor. It doesn't happen in the secure windows.
>A secure window should draw 100% as requested or not at all.
Take for example "night mode" which adds an orange tint to everything. If secure windows don't get such an orange tint they will look out of place. Being able to do post processing effects on secure windows is desirable, so as I said there is a trade off here in figuring out what should be allowed.
ChrisArchitect
Discussion: https://news.ycombinator.com/item?id=45574613
jonplackett
In the previous discussion everyone seems happy it’s been patched and not to worry (even though androids mostly don’t run anything like the latest android)
But in this write up they say the patch doesn’t work fully
charcircuit
The bigger issue is the sidechannel that exists which leaks information from secure windows, even from protected buffers, potentially including DRM protected content.
While these blurs make the sidechannel easier to use as it provides a clear signal, considering you can predict the exact contents of the screen I feel like you could get away with just a mask.
4gotunameagain
Modern devices are simply too complex to be completely secure.
We have this tendency of adding more and more "features", more and more functionality 85% of which nobody asked for or has use for.
I believe that there will be a market for a small, bare bones secure OS in the future. Akin to how freeBSD is being run.
globalhsbc
[dead]
Things like this make me wonder if the social media giants use attacks like these to gain certain info about you and advertise to you that way.
Either that or Meta's ability to track/influence emotional state by behaviour is that good that they can advertise to me things I've only thought of and not uttered or even searched anywhere.