EDIT

TO EVERYONE ASKING TO OPEN AN ISSUE ON GITHUB, IT HAS BEEN OPEN SINCE JULY 6: https://github.com/LemmyNet/lemmy/issues/3504

June 24 - https://github.com/LemmyNet/lemmy/issues/3236

TO EVERYONE SAYING THAT THIS IS NOT A CONCERN: Everybody has different laws in their countries (in other words, not everyone is American), and whether or not an admin is liable for such content residing in their servers without their knowledge, don’t you think it’s still an issue anyway? Are you not bothered by the fact that somebody could be sharing illegal images from your server without you ever knowing? Is that okay with you? OR are you only saying this because you’re NOT an admin? Different admins have already responded in the comments and have suggested ways to solve the problem because they are genuinely concerned about this problem as much as I am. Thank you to all the hard working admins. I appreciate and love you all.

ORIGINAL POST

You can upload images to a Lemmy instance without anyone knowing that the image is there if the admins are not regularly checking their pictrs database.

To do this, you create a post on any Lemmy instance, upload an image, and never click the “Create” button. The post is never created but the image is uploaded. Because the post isn’t created, nobody knows that the image is uploaded.

You can also go to any post, upload a picture in the comment, copy the URL and never post the comment. You can also upload an image as your avatar or banner and just close the tab. The image will still reside in the server.

You can (possibly) do the same with community icons and banners.

Why does this matter?

Because anyone can upload illegal images without the admin knowing and the admin will be liable for it. With everything that has been going on lately, I wanted to remind all of you about this. Don’t think that disabling cache is enough. Bad actors can secretly stash illegal images on your Lemmy instance if you aren’t checking!

These bad actors can then share these links around and you would never know! They can report it to the FBI and if you haven’t taken it down (because you did not know) for a certain period, say goodbye to your instance and see you in court.

Only your backend admins who have access to the database (or object storage or whatever) can check this, meaning non-backend admins and moderators WILL NOT BE ABLE TO MONITOR THESE, and regular users WILL NOT BE ABLE TO REPORT THESE.

Aren’t these images deleted if they aren’t used for the post/comment/banner/avatar/icon?

NOPE! The image actually stays uploaded! Lemmy doesn’t check if the images are used! Try it out yourself. Just make sure to copy the link by copying the link text or copying it by clicking the image then “copy image link”.

How come this hasn’t been addressed before?

I don’t know. I am fairly certain that this has been brought up before. Nobody paid attention but I’m bringing it up again after all the shit that happened in the past week. I can’t even find it on the GitHub issue tracker.

I’m an instance administrator, what the fuck do I do?

Check your pictrs images (good luck) or nuke it. Disable pictrs, restrict sign ups, or watch your database like a hawk. You can also delete your instance.

Good luck.

  • shagie@programming.devEnglish
    2·
    1 year ago

    Do you have a good and reasonable reverse DNS entry for the device you’re writing this from?

    FWIW, my home network comes nat’ed out as {ip-addr}.res.provider.com.

    Under your approach, I wouldn’t have any system that I’d be able to upload a photo from.

      • shagie@programming.devEnglish
        1·
        1 year ago

        If you’re whitelisting *.res.provider.com and *.mobile.att.com the whitelist is rather meaningless because you’ve whitelisted almost everything.

        If you are not going to whitelist those, do you have any systems available to you (because I don’t) that would pass a theoretical whitelist that you set up?

          • shagie@programming.devEnglish
            1·
            1 year ago

            Would you be able to post an image if neither *.res.provider.com nor *.mobile.att.com were whitelisted and putting 10-11-23-45.res.provider.com (and whatever it will be tomorrow) was considered to be too onerous to put in the whitelist each time your address changed?

              • shagie@programming.devEnglish
                1·
                1 year ago

                If you have whitelisted *.mobile.att.net you’ve whitelisted a significant portion of the mobile devices in the US with no ability to say “someone in Chicago is posting problematic content”.

                You’ve whitelisted 4.6 million IPv4 addresses and 7.35 x 1028 IPv6 addresses.

                Why have a whitelist at all then?

                • PuppyOSAndCoffee@lemmy.mlEnglish
                  1·
                  1 year ago

                  We should assume most users are not going to be criminals.

                  For users who are criminals, instance administrators are on the hook to help the feds catch the bad guys. If the bad guys are using mobile devices, it’s a slam dunk right?

                  100% in a democratically elected country governed by the rule of law, an instance admin should be handing over logs to their regional authorities to pursue child pornographers to the full extent possible.

                  One assumes most child pornographers know this, so they are going to use other methods to mask their IP. Those other methods are going to be filtered out by DNS whitelist - even if a user utilized a mobile device 99% of the time, the minute they try to anonymize their criminal content, it’s more likely to be gated right at the source.