I noticed a bit of panic around here lately and as I have had to continuously fight against pedos for the past year, I have developed tools to help me detect and prevent this content.
As luck would have it, we recently published one of our anti-csam checker tool as a python library that anyone can use. So I thought I could use this to help lemmy admins feel a bit more safe.
The tool can either go through all your images via your object storage and delete all CSAM, or it canrun continuously and scan and delete all new images as well. Suggested option is to run it using --all once, and then run it as a daemon and leave it running.
Better options would be to be able to retrieve exact images uploaded via lemmy/pict-rs api but we’re not there quite yet.
Let me know if you have any issue or improvements.
EDIT: Just to clarify, you should run this on your desktop PC with a GPU, not on your lemmy server!
based db0 releasing great tools and maintaining a great community
Opened a relevant issue: https://github.com/LemmyNet/lemmy/issues/3920
Hi db0, if I could make an additional suggestion.
Add detection of additional content appended or attached to media files. Pict-rs does not reprocess all media types on upload and it’s not hard to attach an entire .zip file or other media within an image (https://wiki.linuxquestions.org/wiki/Embed_a_zip_file_into_an_image)
Currently I delete on PIL exceptions. I assume if someone uploaded a .zip to your image storage, you’d want it deleted
The fun part is that it’s still a valid JPEG file if you put more data in it. The file should be fully re-encoded to be sure.
In that case, PIL should be able to read it, so no worries
But I could take ‘flower.jpg’, which is an actual flower, and embed a second image, ‘csam.png’ inside it. Your scanner would scan ‘flower.jpg’, find it to be acceptable, then in turn register ‘csam.png’. Not saying that this isn’t a great start, but this is the reason that a lot of websites that allow uploads re-encode images.
my pict-rs already re-encodes everything. This is already a possibility for lemmy admins
Good to hear they have that covered already. Looks like a great tool!
As @[email protected] stated. They’re still valid image files, they just have extra data.
Just going to argue on behalf of the other users who know apparently way more than you and I do about this stuff:
WhY nOt juSt UsE thE FBi daTaBaSe of CSam?!
(because one doesn’t exist)
(because if one existed it would either be hosting CSAM itself or showing just the hashes of files - hashes which won’t match if even one bit is changed due to transmission data loss / corruption, automated resizing from image hosting sites, etc)
(because this shit is hard to detect)
Some sites have tried automated detection of CSAM images. Youtube, in an effort to try to protect children, continues to falsely flag 30 year old women as children.
OP, I’m not saying you should give up, and maybe what you’re working on could be the beginning of something that truly helps in the field of CSAM detection. I’ve got only one question for you (which hopefully won’t be discouraging to you or others): what’s your false-positive (or false-negative) detection rate? Or, maybe a question you may not want to answer: how are you training this?
I’m not training it. Im using publicly available clip models.
The false positive rate is acceptable. But my method is open source so feel free to validate on your end
Acceptable isn’t a percentage, but I see in your opinion that it’s acceptable. Thanks for making your content open source. I do wish your project the best of luck. I don’t think I have what it takes to validate this myself but if I end up hosting an instance I’ll probably start using this tool more often myself. It’s better than nothing at at present I have zero instances but also zero mods lined up.
I saw you mention that you were working on this - props for getting it out so quickly!
