cross-posted from: https://lemmy.cat/post/6385
It is currently possible, through Lemmy's API, to create accounts automatically and without limit if verification by email address or captcha is not activated. I'd advise you to activate one or both of them NOW!
After registering x number of accounts (currently I could do thousands), all you have to do is list all the existing communities for each of the account to publishes one new post per community, or more. I'll leave you to picture the mess.
(I apologise to the administrators of sh.itjust.works, I should have done the test with my own server.)
It might be broken, but it's also a matter of setting up enough of an obstacle for bot operators. By having a captcha, it limits them to using software that has the ability to break a captcha, and that might be enough trouble that they go elsewhere to easier targets, as opposed to having no captcha, and letting them run wild with anything that they already have.
Even tools like that have rate limits and things that would be just as much of a small obstacle.