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The issue described here, to my understanding, is that you find or create csam and then manipulate it so that its fingerprint collides with another image that y
by bastawhiz 3y ago
The issue described here, to my understanding, is that you find or create csam and then manipulate it so that its fingerprint collides with another image that you want to be flagged as csam. You then submit the manipulated version of the found or generated image to the authority.
First, at what point does the authority go "uh... Where did you get this from?" Practically speaking, the people doing this would have to be authorized law enforcement, no? Like if an ordinary citizen showed up with csam the excuse "oh I found this JPEG in a trunk in my late grandpa's attic" isn't gonna fly.
My assumption is that the central authority that compiles the database isn't just taking fingerprints, they want the actual source images. And I'm assuming they actually look at them to ensure they are, in fact, csam. Otherwise anyone could put anything into the database.
Now let me be very clear: I hate the idea of my device scanning for csam on principle. But what's the attack here? That someone looks at my device and determines that I do not, in fact, have csam? And that false positive might even be investigated and reveal that the bad actor sought out or generated CSAM for the purposes of perpetrating this! Which is even worse!
If the police want to look at your device, they can do that already through any number of other sketchy means that don't involve what's likely weeks of effort. The US searches phones at the border when they're feeling like it. I don't want to defend this stuff, but the potential for abuse in this specific case seems vanishingly small.
- pydry 3y agoMy understanding was that you generate a csam with a colliding fingerprint and put it online and trick somebody with an iPhone or whatever into clicking on it. Now they're on a watchlist and will get harassed by the police.
- bastawhiz 3y agoSo you have to plant the manipulated csam somewhere that it'll be found by law enforcement and added to the database and just hope you did a good enough job to not be tracked?
- deleted 3y ago[deleted]
- contravariant 3y agoLook if I want to host some white noise I can't be held responsible for what happens if people xor it together with some other file hosted elsewhere.
- pydry 3y ago>just hope you did a good enough job to not be tracked Right. Your target uses e.g. an iPhone. You use Kali on clean hardware.
- graypegg 3y agoI guess it comes down to this black box list of hashes that no one would want to audit for pretty obvious reasons. The authority is only as good as the person paid to automate the hashing process feels that day. It’s not inconceivable that someone at the authority could put in an image known to be stored by someone else into the hash list just to cause an extremely scary and confusing month for that person. To be fair, that’s also the same problem of say, someone at your ISP dislikes you. There’s always a chance your supplier has a “bad apple”. Maybe it’s not an issue but I get the idea.
- rootusrootus 3y ago> I guess it comes down to this black box list of hashes that no one would want to audit for pretty obvious reasons. The authority is only as good as the person paid to automate the hashing process feels that day. Isn't that exactly how it is run today, however? There are actual people at the National Center for Missing & Exploited Children who maintain the database and do in fact get incidentally exposed to the imagery. It's the one organization in the entire nation allowed to legally possess the actual images.
- Kevin605 3y agoThe general public submitting CSAM directly would indeed be highly unlikely, but the scenario we need to consider involves those in positions of authority who can manipulate systems behind the scenes. Imagine that an unflattering or satirical image of Viktor Orban is circulating in France, and let's say it becomes viral, inciting discussions that the Hungarian government finds detrimental to its international image. The authorities might want to suppress this image, not just within Hungary but also in the whole of European Union. The Hungarian government - who presumably has access to the EU CSAM database (or can coerce those who do), might attempt to add a fingerprint of a manipulated CSAM image that collides with the fingerprint of the satirical image. The principle here is not for public individuals to submit CSAM directly but for government actors to manipulate systems clandestinely.
- pbhjpbhj 3y agoWon't that easily be found out when the hash matches the image of Viktor Orban rather than an image of CSAM. I'm not sure the legal system is as stupid as you think it is. Then Hungary would just have their hashes reviewed. Sure a conspiracy of all the relevant authorities across the whole EU would work, ... but that seems a stretch to enable what, political elites to _cooperatively_ censor images the public hold. There are easier ways, surely.
- giantrobot 3y agoThe point is a real CSAM image can be manipulated such that when hashed it matches the hash of the Orban image. So your phone calls the police saying you have CSAM when you get the Orban image. Your life is ruined and you're financially impacted trying to defend yourself. Even if you're cleared of charges you're fucked. This now has a chilling effect on sharing of the Orban image. Orban's people won't face any pushback because they submitted an actual CSAM image. It's on you to prove somehow they intentionally poisoned the CSAM image such that its hash matches the Orban image.
- slg 3y agoI get people's opinions of law enforcement are low, but do you really think that no one would question why a huge number of people have a single CSAM image on their device especially when the hash for that image was just added to the database? Do you think that no one would question that maybe there is something wrong with that hash? Do you think that no one would look at the flagged image on any of those devices? I understand people's concerns with this tech, but this seems like a rather silly hypothetical to me.
- NoMoreNicksLeft 3y ago> You then submit the manipulated version of the found or generated image to the authority. If this is easy (for some definition of easy), is it not easy to then alter the CSAM images every they trade it to another pervert, such that hashes never match? How much image alteration would that take?, would it be human perceptible? If perceptible, would it be ignorable? I think the exploit here suggests that the whole system may end up obsolete sooner rather than later.
- deleted 3y ago[deleted]
- baby_souffle 3y agoWould this org refuse to accept CSAM from an anonymous source just because they can’t point to its origin?
- bastawhiz 3y agoI think they'd send some police to find out
- npteljes 3y agoAnother version of the attack is to manipulate an innocent image in a way that's flagged by detection systems, and then spread that image somehow. If any of the responses are automatic, then it's a lot of false positives in the system, a lot of contact from police, disabling of the host, things like this.
- boerseth 3y agoThere's also not really any need to trick the system or manipulate other files to generate collisions. Spreading one of the original law-breaking files to unwilling targets would work as a trigger just the same.
- LorenPechtel 3y agoBut the recipient would know they had gotten CSAM and wouldn't pass it along.
- pornel 3y agoAbusers who have actual CSAM could intentionally publish the fingerprints to sabotage the scanning scheme. If the illegal fingerprints become known, it will be possible to generate false positives and overwhelm verification/enforcement with bogus matches.
- Muromec 3y ago>Like if an ordinary citizen showed up with csam the excuse "oh I found this JPEG in a trunk in my late grandpa's attic" isn't gonna fly Just post it to 4chan, it’s actively monitored by intelligence services
- throwing_away 3y agoAlso by unintelligent services
- astrange 3y agoThis post shows you either don't know what CSAM is or what an intelligence service is.