On February 15th, newly-created Fediverse accounts started posting spam messages from various instances, sending invites to a Discord server for a Japanese troll organization. This spam was widespread across the Fediverse. The posts frame ap12 from “KuronekoServer” as the culprit behind the operation.
Looking at their spam content (in Japanese)
how did it take this long to get spam on the fediverse it’s basically an open canvas for wet crap
There have been other waves, it’s just that once they get shut down everybody loses interest and moves on. The PR for the one of the changes Mastodon just made was implemented in May 2023 after the Doge spam wave. And here’s a June 2019 post talking about exactly the same kind of attack: “The problem we are experiencing is the spammer signing up on random open instances and sending spam remotely.”