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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

#61

Post by robertoandred »

onepunchedman wrote: post #43
onepunchedman wrote: post #41

Earlier quoted context omitted.

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.

What exactly would you be charged with? Why would law enforcement even be involved in a case of false positives?

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

#62

Post by colordrops »

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?

They had to have been coerced.

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

#63

Post by arsome »

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.

The even worse part here is that not only could it impact an image of a beautiful sunset, which would fail the human check, it could impact a low quality version of legal porn, which could easily pass the human check and get passed on to law enforcement.

A sufficiently advanced catfishing attack could probably take advantage of this to get someone raided and have all their electronics confiscated.

Just send someone a zip of photos and let them extract it...

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

#64

Post by dragonwriter »

dannyw wrote: post #53
endisneigh wrote: post #40

Why does matter? The photo looks nothing like the target? If someone looks at the two images wouldn’t they see they’re not the same and therefore the original image was mistakenly linked with the target

Apple's reviewers, by law, cannot look at the target. No one except NCMEC is allowed to possess the target (CSAM material). So Apple will be looking at a low-res grayscale image of whatever the collided image is, which could be legal adult pornography (let's say: a screengrab of legal "teen" 18+ porn), but the CSAM filter tells it that it's abuse material! What would you do as the Apple reviewer? (Hint: You only have…

> Apple's reviewers, by law, cannot look at the target

This is false.

> No one except NCMEC is allowed to possess the target (CSAM material).

False. No one is allowed to knowingly possess it, without taking certain actions forthwith when they become aware of it. Obviously, prior to it being reviewed as it is, neither the reviewer nor Apple has knowledge that it is actual or even particularly likely CSAM.

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

#65

Post by EGreg »

dannyw wrote: post #30
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…

The "send known CSAM" attack has existed for a while but never made sense. However, this technology enables a new class of attacks: "send legal porn, collided to match CSAM perceptual hashes". With the previous status quo: 1. The attacker faces charges of possessing and distributing child pornography 2. The victim may be investigated and charged with child pornography if LEO is somehow alerted (which requires work, a…

So, everyone is going to turn off their iCloud sync and they won’t be a target anymore?

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

#67

Post by throwaway384950 »

Some people seem to be confused why a hash collision of a cat and a dog matters. Here's a potential attack: share (legal) NSFW pictures that are engineered to have a hash collision with CSAM to get someone else in trouble. The pictures are flagged as CSAM, and they also look suspicious to a human reviewer (maybe not enough context in the image to identify the subject's age). To show that this can be done with real NSFW pictures, here is an example, using an NSFW image from a subreddit's top posts of all time.

Here is the image (NSFW!): https://i.ibb.co/Ct64Cnt/nsfw.png

Hash: 59a34eabe31910abfb06f308

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

#68

Post by copperx »

dannyw wrote: post #30
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…

The "send known CSAM" attack has existed for a while but never made sense. However, this technology enables a new class of attacks: "send legal porn, collided to match CSAM perceptual hashes". With the previous status quo: 1. The attacker faces charges of possessing and distributing child pornography 2. The victim may be investigated and charged with child pornography if LEO is somehow alerted (which requires work, a…

It seems like I'm not going to sleep tonight.

Sure, there is hyperbole in OP's comment (CSAM ransomware and automated law enforcement aren't a thing yet), but we're a few steps from that reality.

Even worse, how long will it take until other cloud storage services such as Dropbox, Amazon S3, Google Drive et al implement the same features? Or worse, required by law to do so?

This sounds like the start of an exodus from the cloud, at least in the non-developer consumer space.

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

#69

Post by onepunchedman »

robertoandred wrote: post #58
onepunchedman wrote: post #52

Earlier quoted context omitted.

I 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.

What kind of social engineering would lead an innocent person to save known CSAM to their photo library?

Lending 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.

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

#70

Post by robertoandred »

throwaway384950 wrote: post #67

Some people seem to be confused why a hash collision of a cat and a dog matters. Here's a potential attack: share (legal) NSFW pictures that are engineered to have a hash collision with CSAM to get someone else in trouble. The pictures are flagged as CSAM, and they also look suspicious to a human reviewer (maybe not enough context in the image to identify the subject's age). To show that this can be done with real NS…

Does anyone save porn to their personal photo libraries? Especially porn as suspicious as the image you posted?
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