Facebook Following Links to my Nextcloud?

[Gerowen]

Random observation. Ever since I started this new Facebook account, out of a concern for personal privacy (because Facebook is shady as hell), I've been avoiding, to the best of my ability, posting any content directly to Facebook. Pictures and videos and such are almost always links to my personal Nextcloud server, and most of those links are set to expire after 30 days. My logic was that they wouldn't bother traversing external links because they must get bombarded with a billion of them every hour, and to do so wouldn't be worth their time. I was wrong. A few minutes ago I noticed that somebody had accessed a file in a folder that I had shared publicly from my Nextcloud. The links to those shares are random and unique, so the chances of somebody guessing the address are basically zero, so they had to get it from me directly via one of the posts or messages I had sent. The weird thing is, the folder had been shared literally months ago, and I hadn't posted any links to it since the original, so it's not even like somebody could have just happened across it, somebody would have had to be specifically looking months into the past on my timeline, and I don't think I even posted the link publicly, I think I only sent it to a couple of specific people directly via Facebook Messenger.

So I checked the logs on my server to get the IP address, then ran a whois on one of the IPs, and guess who is snooping around in the public links on my server and randomly downloading files that don't concern them? None other than Facebook themselves. They appear to just be randomly snooping around and downloading files from any of the public links I've shared here, so I'll have to be a little more cautious. It's not even just images, one of the affected files was an audio recording, and that file was inside a folder, so they weren't pulling thumbnail images for previews or anything, they intentionally followed a link I sent via Messenger and downloaded files that didn't concern them.

 

[shockz]

The moment you share anything via Facebook, it's crawled, processed and archived. You can't even post a link without it generating a preview and parsing text for the headliner on a link people click... and there's probably all sorts of automated checks and reviews later down the road too.Their EULA also covers them on this type of behavior.

tl;dr: Are you really surprised about this?

[Gerowen]

On 24/01/2023 at 22:47, shockz said:

The moment you share anything via Facebook, it's crawled, processed and archived. You can't even post a link without it generating a preview and parsing text for the headliner on a link people click... and there's probably all sorts of automated checks and reviews later down the road too.Their EULA also covers them on this type of behavior.

tl;dr: Are you really surprised about this?

Not that they crawled the link when I sent it, no. But that they started randomly checking files at a link I sent out months ago? Yes. I checked all the IPs that had viewed that file, thinking maybe somebody opened it and triggered a scan but nope, every IP that had visited the share was owned by Facebook.