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Show HN: Simple demo of a cold boot attack using a Raspberry Pi

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Re: Show HN: Simple demo of a cold boot attack using a Raspberry Pi

#11

Post by yonatan8070 »

anfractuosity wrote: post #7
Cheer2171 wrote: post #6

It is important to note they could access an image in the memory up to 0.75 seconds after cutting power, but after 1.0 seconds everything had completely decayed. This sounds less like a "cold boot" attack and more like the residual power is still flowing on the substrate for 0.75 seconds.

I wasn't able to automate the use of the freeze spray alas, but I believe that did let me access data after more significant durations. With the freeze spray I did also manage to unplug the power cable completely and switch SD cards manually. Edit: In "Cold Boot Attacks are Still Hot: Security Analysis of Memory Scramblers in Modern Processors" they say "To assess the feasibility of cold boot attacks on today’s dense…

What results would you expect to get if you simply put the whole setup in a regular freezer? Or if you just tried it during winter

Re: Show HN: Simple demo of a cold boot attack using a Raspberry Pi

#12

Post by anfractuosity »

yonatan8070 wrote: post #10

It would be interesting to do this with different delays to see how the noise level increases as the delay increases, then once you have a bunch of images recovered, make an animation of the image getting more and more noisy as the time increases, would also be interesting to compare the results for different ambient temperatures, how much more feasable would this be during January in Norway vs August in Texas?

That's something they did in one of the original papers - "Lest We Remember: Cold Boot Attacks on Encryption Keys" by Halderman et al, with an earlier version of DDR, think it was DDR2.

It's something I'd like to try too. Good point re. the temperature also, I bought a PT100 temperature probe I need to use to measure the surface temperature of the RAM chip too.

Re: Show HN: Simple demo of a cold boot attack using a Raspberry Pi

#13

Post by anfractuosity »

yonatan8070 wrote: post #11
anfractuosity wrote: post #7

Earlier quoted context omitted.

I wasn't able to automate the use of the freeze spray alas, but I believe that did let me access data after more significant durations. With the freeze spray I did also manage to unplug the power cable completely and switch SD cards manually. Edit: In "Cold Boot Attacks are Still Hot: Security Analysis of Memory Scramblers in Modern Processors" they say "To assess the feasibility of cold boot attacks on today’s dense…

What results would you expect to get if you simply put the whole setup in a regular freezer? Or if you just tried it during winter

It sounds like a typical freezer cools to around -20C, I think the freezer spray I used directly on DDR chip, claims to chill to around -50C, but not sure how much the surface temperature decreases after spraying and how fast it warms up again.

Re: Show HN: Simple demo of a cold boot attack using a Raspberry Pi

#18

Post by PrimeMcFly »

oskarw85 wrote: post #17

It's nice to recover an image but encryption keys are not that. One bit flip and it's game over. This experiment is more useful for human-readable document forensics than anything else.

a passphrase is much shorter than a key and may be in memory multiple times.

Re: Show HN: Simple demo of a cold boot attack using a Raspberry Pi

#19

Post by dist-epoch »

oskarw85 wrote: post #17

It's nice to recover an image but encryption keys are not that. One bit flip and it's game over. This experiment is more useful for human-readable document forensics than anything else.

If from a 128 bit key 120 are correct, it's trivial to figure out the others, even if you don't know which bits are the flipped ones.

Cryptographers worry even when a few key bits are leaked.

Re: Show HN: Simple demo of a cold boot attack using a Raspberry Pi

#20

Post by orlp »

oskarw85 wrote: post #17

It's nice to recover an image but encryption keys are not that. One bit flip and it's game over. This experiment is more useful for human-readable document forensics than anything else.

Alright let's test this hypothesis. Load up a bitcoin wallet and post the private key here with 1 random bit flip :)
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