
Windows desktop GPU memory leaking into Linux screenshare app - nh2
https://github.com/nh2/video-memory-across-reboots
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nh2
Hi,

I accidentally found that my Linux screenshare program is able to send
leftover video memory from a previous Windows boot (shut down 5 days ago) over
the Internet, showing the private Windows desktop contents of the last logged
in user.

This doesn't seem good security-wise for all parts involved.

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colejohnson66
I’m surprised that the video RAM doesn’t decay almost instantly when the power
shuts off, but not for _five days_?! From my understanding, the whole
computer, including the graphics card, shuts off when you power off a
computer. That means that the video RAM is being written to non volatile
storage somewhere.

My only guess: Do you have Windows Quick Start turned on? Because that doesn’t
shut down the computer all the way; it just puts it in a deep sleep (i.e. the
graphics card and its RAM are still powered)

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nh2
The machine was _rebooted_ directly from Windows into Linux, not power-shut-
off.

I'm not complaining about the lack of physical decay in DRAM, but about
software.

~~~
colejohnson66
Hmm. That might be it. I don’t think the power gets cut when you reboot; the
processor just resets itself to its starting state.

I think the reason this hasn’t been addressed is because, from my
understanding of the problem, people don’t reboot to a different OS running at
a different resolution, so the problem was never noticed

