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Why would anyone save CSAM to their photo library?
by robertoandred 5y ago
Why would anyone save CSAM to their photo library?
- dannyw 5y agoA hash collision allows you to create material that matches CSAM signatures, without being CSAM. This opens up a new class of attacks. Specifically, many criminal actors don't touch CSAM because it's wrong. But some of these criminal actors will happily abuse legal systems, e.g. SWATTing.
- seph-reed 5y agoI would gladly have a mobile phone full of memes that have been modified to match, just for the lulz. I honestly think every meme should be put through just to have "illegal memes"
- zepto 5y ago> A hash collision allows you to create material that matches CSAM signatures, without being CSAM. This is not correct. Hash collisions won’t match the visual derivative.
- foerbert 5y agoThat bit you quoted seems to be actually correct. It does not mention visual derivatives at all. That said I think your statement is a bit too strong, but generally true. A hash collision is not going to inherently be visually confusing. However you claim that it is impossible for an image to be both visually confusing and a hash collision, which seems unlikely. The real question is going to be how much more effort it takes to do both.
- zepto 5y agoI didn’t claim it was impossible, just that hash collisions won’t match both. Also, the information needed to create a full match simply is not available.
- foerbert 5y agoAre those not the same statement? Unless you're relying on it being computationally infeasible, but I'm not sure we know enough to consider that true at this point. Usually when we make statements on those grounds we do so with substantial proof. I don't think we know enough to do so here. I'm not even sure how feasible it is when you throw DL into the mix.
- zepto 5y ago> Are those not the same statement? No.
- zepto 5y agoFrom the docs: “as an additional safeguard, the visual derivatives themselves are matched to the known CSAM database by a second, inde- pendent perceptual hash. This independent hash is chosen to reject the unlikely possi- bility that the match threshold was exceeded due to non-CSAM images that were ad- versarially perturbed to cause false NeuralHash matches against the on-device en- crypted CSAM database.”
- saithound 5y ago
- onepunchedman 5y agoMost people wouldn't of course. In this scenario you'd get someone to download the CSAM unknowingly. If they have iCloud sync it automatically uploads to iCloud, thereby triggering the system. At that point the authorities will be alerted by Apple, and you can inform media outlets. They in turn will ask law enforcement who will confirm the investigation, and the reputation of the person investigated will be tarnished.
- robertoandred 5y agoYou specifically said someone would be sent known CSAM. How would that get added to their photo library?
- onepunchedman 5y agoI meant * could *. My point is that social engineering is a clear weak link in this system. They can also be sent regular photos whose hash matches the database, or use this repo to transform a regular pornographic photo's hash, making it hard for manual confirmation on Apple's part.
- robertoandred 5y agoWhat kind of social engineering would lead an innocent person to save known CSAM to their photo library?
- onepunchedman 5y agoLending your phone to someone for a call, then a quick airdrop. Legitimate-looking emails with buttons. There's probably a list somewhere of proven attack vectors.
- copperx 5y agoNone needed. You could just send a photo to the target through WhatsApp, and the photo would be automatically synced with iCloud.
- systemvoltage 5y agoI posted another comment that was misunderstood as well. Folks, no one is proposing to download actual CSAM images to your photo lib. You could be duped thinking you downloaded an image of a beautiful sunset which was carefully manipulated to match the hash of an actual CSAM image.
- onepunchedman 5y agoThis is the really scary part. Of course getting someone to download blobs that corrolate to CSAM would be one thing, but downloading regular photos that have nefarious hashes is a trend /pol/ could start in an afternoon.
- deleted 5y ago[deleted]
- robertoandred 5y agoThe parent was proposing to “just send known CSAM”. But OK, say someone sends you a sunset that fools the hasher. Then what? Of course one match won’t do anything, so you’d need to download however many matching sunsets. Then what? The Apple reviewer would see they’re sunsets and you’d challenge the flag saying they’re sunsets. And if somehow NCMEC got involved, they’d see they’re just sunsets. And if law enforcement got involved, they’d see they’re just sunsets. These proofs of concept might seem interesting from a ML pov, but all they do is just highlight why Apple put so many layers of checking into this.
- systemvoltage 5y agoIt would still be mentally draining to be accussed of CP. Can you imaging how terrified one would be if they see a warning message with a blurred sunset? I don't know exactly how the system works but from Apple's press release, it hides the image and gives a warning to the user. This would not go well on social media.
- netr0ute 5y agoThe point isn't to trick NCMEC, but rather create a DoS attack so no actual triggers can get through the noise.