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)
A first step is RBL intergration, a shared blocklist of spam instances that subscribed instances would use to blackhole spam users/traffic/instances. These are used ubiquitously in email spam systems, so there is a precedent in federation systems for it working. We need to stand up an RBL, and then mod Lemmys federation system to work automatically based on the community blocklist.
It does mean that poorly admined instances will get blackholed, breaking their federation, but that’s the cost of a healthy network.