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Hash collision in Apple NeuralHash model

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Re: Hash collision in Apple NeuralHash model

#291

Post by floatingatoll »

shapefrog wrote: post #120
lifthrasiir wrote: post #10

Earlier quoted context omitted.

But you can essentially perform DoS attack to human checkers, effectively rendering the entire system grind to a halt. The entire system is too reliant on the performance of NeuralHash which can be defaced in many ways. [1] (Added later:) I should note that the DoS attack is only possible with the preimage attack and not the second preimage attack as the issue seemingly suggests, because you need the original CSAM to…

I have seen it suggested that everyone should flood the system with flagged images to overwhelm it in protest to this move by apple. Sounds pretty stupid to me to fill your phone with kiddie porn in protest, but you do you internet people.

It’s incredibly stupid because your Apple ID will get terminated for abusing Apple services.

Re: Hash collision in Apple NeuralHash model

#292

Post by grishka »

UncleMeat wrote: post #109

Why is this meaningfully different than, say, what Google Photos has been doing for years? If you can get rooting malware on the target device then you could 1. Produce actual CSAM rather than a hash collision 2. Produce lots of it 3. Sync it with Google Photos This attack has been available for many years and does not need convoluted steps like hash collisions if you have the means to control somebody's phone with a…

The big difference is that cloud providers do the scanning on their own infrastructure. If you don't want something scanned, you don't upload it to the could, that simple. But here, your own device is snitching on you.

Re: Hash collision in Apple NeuralHash model

#293

Post by rollinggoron »

bo1024 wrote: post #152
Edd314159 wrote: post #105

I think I am in dire need of some education here and so I have questions: * Is this a problem with Apple's CSAM discriminator engine or with the fact that it's happening on-device? * Would this attack not be possible if scanning was instead happening in the cloud, using the same model? * Are other services (Google Photos, Facebook, etc.) that store photos in the cloud not doing something similar to uploaded photos, w…

Not complete answers but background: apple’s system works by having your device create a hash of each image you have. The hash (a short hexadecimal string) is compared to a list of known CP image hashes, and if it matches, then your image is uploaded to Apple for further investigation. A devastating scenario for such a system is if an attacker knows how to look at a hash and generate some image that matches the hash,…

But how does this exact attack and scenario not also apply to Google, Facebook, Microsoft etc... who are also doing the same thing on their clouds servers?

Re: Hash collision in Apple NeuralHash model

#294

Post by Grustaf »

mlindner wrote: post #281
sandworm101 wrote: post #246

Earlier quoted context omitted.

>> useful for areas where Apple really doesn't want to even look at the actual material Correct. It has plausible deniability built in. Apple is unable to verify that the images the government are looking for are actually CSAM. They could be political. They could be protest images. They could be Winnie the Pooh. Apple can plead ignorance as it blindly scans for whatever the requesting government asks it to scan for.…

> Nobody really minds that this system is going to be used for CSAM. I beg to differ. It doesn't matter how evil the content is, no scanning of my computers by outside parties, period. More so by scanning law enforcement can even plant legitimate child pornography on people's computers and get convictions all the easier because the system self-reports.

It's clearly not the scanning you are opposed to, it's the reporting. Apple apps, well a lot of apps, already scan all your content, for classifying images, doing OCR, extracting dates and addresses etc. That is nothing new, it's omnipresent.

Re: Hash collision in Apple NeuralHash model

#295

Post by jodrellblank »

ethbr0 wrote: post #255
sandworm101 wrote: post #246

Earlier quoted context omitted.

>> useful for areas where Apple really doesn't want to even look at the actual material Correct. It has plausible deniability built in. Apple is unable to verify that the images the government are looking for are actually CSAM. They could be political. They could be protest images. They could be Winnie the Pooh. Apple can plead ignorance as it blindly scans for whatever the requesting government asks it to scan for.…

Why even keep Apple in the loop? Why not just allow government to submit scanning models directly? Which Apple will dutifully install and run, because they're required by local laws.

> "Which Apple will dutifully install and run, because they're required by local laws."

Which Apple have stated that they won't do, and have designed the system so they can't do that without it being found out: https://news.ycombinator.com/item?id=28221082

Can't you at least post accurate information about this system and support outrage based on facts instead of fantasy?

Re: Hash collision in Apple NeuralHash model

#296

Post by [deleted] »

FabHK wrote: post #18

How can you use it for targeted attacks? This is what would need to happen: 1. Attacker generates images that collide with known CSAM material in the database (the NeuralHashes of which, unless I'm mistaken, are not available) 2. Attacker sends that to innocent person 3. Innocent person accepts and stores the picture 4. Actually, need to run step 1-3 at least 30 times 5. Innocent person has iCloud syncing enabled 6.…

[deleted]

Re: Hash collision in Apple NeuralHash model

#298

Post by jkestner »

jodrellblank wrote: post #276
mschuster91 wrote: post #178

Earlier quoted context omitted.

> and there is no law who requires them to "scan" on device Yet . The demands by "concerned parents" (aka fronts for secret services, puritans/other religious fundamentalists and law-and-order hardliners) to "do something against child porn" have grown ever more strong and insane over the last years. (And you can bet that what is used on CSAM will immediately be used to go after legal pornography, sex work, drug enfo…

> " and what is suspiciously lacking in Apple's response: what are they going to do when they are compelled to extend the CSAM scanner by law in the US, India, China and/or EU? " from https://daringfireball.net/linked/2021/08/09/apple-csam-faq - " we will not accede to any government’s request to expand it. " From https://www.msn.com/en-us/news/technology/craig-federighi-sa... - " “We ship the same software in China…

A “government’s request” is different from a country’s law. “This process” is not the only process by which third parties can breach your privacy.

Re: Hash collision in Apple NeuralHash model

#300

Post by simcop2387 »

tantalor wrote: post #286
ethbr0 wrote: post #248

Earlier quoted context omitted.

That's an incomplete statement. Currently, they must comply with warranty requests by scanning if they have the ability to scan . If they have no such ability (say, because they designed their phones from a privacy-first perspective), the law makes no requirement that they create such a capability. And that's what pisses people off about this.

Can a warrant compel them to develop the capability?

A warrant alone, very likely not. A court order from a judge (slightly different than a warrant), possibly not nut it's not exactly a well tread area of legislation/law. It would probably run afoul of the first amendment given some readings, but it would have to be tested in court and would likely be argued that requiring a backdoor via some law doesn't cause compelled speech or that making that backdoor isn't protected speech etc. It's a relatively new area to be explored.
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