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Show HN: Neural-hash-collider – Find target hash collisions for NeuralHash

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Re: Show HN: Neural-hash-collider – Find target hash collisions for NeuralHash

#41

Post by onepunchedman »

robertoandred wrote: post #36
onepunchedman wrote: post #25

This is just getting wilder and wilder by the day, how spectacularly this move has backfired. As others have commented, at this point all you need is someone willing to sell you the CSAM hashes on the darknet, and this system is transparently broken. Until that day, just send known CSAM to any person you'd like to get in trouble (make sure they have icloud sync enabled), be it your neighbour or a political figure, an…

Why would anyone save CSAM to their photo library?

Most 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.

Re: Show HN: Neural-hash-collider – Find target hash collisions for NeuralHash

#42

Post by systemvoltage »

robertoandred wrote: post #36
onepunchedman wrote: post #25

This is just getting wilder and wilder by the day, how spectacularly this move has backfired. As others have commented, at this point all you need is someone willing to sell you the CSAM hashes on the darknet, and this system is transparently broken. Until that day, just send known CSAM to any person you'd like to get in trouble (make sure they have icloud sync enabled), be it your neighbour or a political figure, an…

Why would anyone save CSAM to their photo library?

I 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.

Re: Show HN: Neural-hash-collider – Find target hash collisions for NeuralHash

#43

Post by onepunchedman »

onepunchedman wrote: post #41
robertoandred wrote: post #36

Earlier quoted context omitted.

Why would anyone save CSAM to their photo library?

Most 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…

Also as dannyw pointed out, you don't even have to send CSAM to trigger the system. If they found you you would still be charged, but not with possession of CSAM.

Re: Show HN: Neural-hash-collider – Find target hash collisions for NeuralHash

#44

Post by Matheus28 »

vermilingua wrote: post #37

The integrity of this entire system now relies on the security of the CSAM hash database, which has just dramatically increased in value to potential attackers. All it would take now, is for one CSAM hash to be known to the public, then uploading collided iPhone wallpapers to wallpaper download sites. That many false positives will overload whatever administrative capacity there is to review reports in a matter of da…

There's no need for someone to get the entire CSAM database. If they go on the darknet and just find enough images (or hashes) that would trip Apple's system, that would be enough. I'd assume any publicly available image on the darknet would likely also be on CSAM.

Re: Show HN: Neural-hash-collider – Find target hash collisions for NeuralHash

#45

Post by onepunchedman »

systemvoltage wrote: post #42
robertoandred wrote: post #36

Earlier quoted context omitted.

Why would anyone save CSAM to their photo library?

I 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.

This 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.

Re: Show HN: Neural-hash-collider – Find target hash collisions for NeuralHash

#46

Post by robertoandred »

onepunchedman wrote: post #41
robertoandred wrote: post #36

Earlier quoted context omitted.

Why would anyone save CSAM to their photo library?

Most 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…

You specifically said someone would be sent known CSAM. How would that get added to their photo library?

Re: Show HN: Neural-hash-collider – Find target hash collisions for NeuralHash

#47

Post by dannyw »

Scaevolus wrote: post #33
dannyw wrote: post #19

Earlier quoted context omitted.

You can extract the hashes with a few hours spent on the darknet. Doing that is certainly illegal and not to mention VERY morally wrong, but criminals exist and criminals won't hesitate to abuse this as a mechanism for framing, extortion, or ransom. It's also possible for someone (Attacker A) to go on the darknet and get a list of 96-bit neural hashes, and then publish or sell this list somewhere to another party, At…

One of the grosser clean room designs. It's certainly possible, but I posit that the exploit chain necessary to get the capability to inject photos onto an arbitrary user's iPhone is valuable enough that it's more likely to be used for spying by repressive regimes than straight up blackmail-- and if you had such a capability, why bother with hash-colliding permutations of legal pornography? Why not plant CSAM directl…

If you plant CSAM, you must possess, distribute, and transmit CSAM. That creates moral and legal barriers. The median ransomware actor probably finds CSAM repulsive and wrong.

If you plant material that matches CSAM hashes, you do none of that. The median ransomware actor might find this to thje fastest way to collect a thousand monero.

Also, you can distribute 30 media items per message via WhatsApp. There is a configurable setting for WhatsApp to save all received photos to your iCloud photo library. No exploits needed, you could probably weaponise this via an WhatsApp bot.

Re: Show HN: Neural-hash-collider – Find target hash collisions for NeuralHash

#48

Post by bArray »

Scaevolus wrote: post #17

NeuralHash collisions are interesting, but the way Apple is implementing their scanner it's impossible to extract the banned hashes directly from the local database. There are other ways to guess what the hashes are, but I can't think of legal ones. > Matching-Database Setup. The system begins by setting up the matching database using the known CSAM image hashes provided by NCMEC and other child-safety organizations.…

To defeat this, all you need to be is a state actor with a database of child porn at your disposal (which is stored for exactly the purpose of training detection systems). Then you run the hashing algorithm against images you know are in the database (Apple suggested that they would accept suggestions by some kind of multi-Country vote). Then you can pull out the hashes and figure out how to trigger false positives on the important vectors.

Next, embed your images in sites of interest, like:

* A meme in some group

* A document or 'leak'

* An email to a journalist

Wait for somebody to save it to their Apply device. Wait for it to be flagged and then use that as 'reasonable means to conduct a search'. When asking for a warrant, the agency would say something like "we detected possible CSAM on a device, the likelihood of a false match is extremely low" - a judge will hardly press further.

You now essentially have a weapon where you can search any Apple device in the name of preventing the distribution of CSAM.

Failing that, you could just have `document_leak.pdf` and download a file that is both a valid PDF and a child porn image, depending on which program you open it with.

Re: Show HN: Neural-hash-collider – Find target hash collisions for NeuralHash

#49

Post by Spivak »

Alupis wrote: post #35

So, what does Apple get out of all this, except negative attention, erosion of their image, possible privacy lawsuits, etc? I just don't understand what Apple's motivation would have been here. Surely this fallout could have been anticipated?

The FBI off their back that they aren’t doing enough to stop the spread of CP.

Re: Show HN: Neural-hash-collider – Find target hash collisions for NeuralHash

#50

Post by Alupis »

Spivak wrote: post #49
Alupis wrote: post #35

So, what does Apple get out of all this, except negative attention, erosion of their image, possible privacy lawsuits, etc? I just don't understand what Apple's motivation would have been here. Surely this fallout could have been anticipated?

The FBI off their back that they aren’t doing enough to stop the spread of CP.

I find it hard to believe CSAM was so pervasive on iDevices that they'd feel compelled to do something about it.

As far as we know (and I'm sure lots of eyeballs are looking now) Android doesn't do this.

And frankly, why would Apple care that the FBI isn't cozy with them. Their entire brand is "security and privacy", kind of goes against most 3 Letter Agencies anyway.

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