Zendesk conversations tend to follow a standard template that's easy to recognise. They also often mention Zendesk in the footer ("Delivered by Zendesk").

Either way, someone shared a much more minimal version [1] on my gist, which should be safe to use as long as you're not signing up for a Zendesk site. Most of the recent spam emails have been about Zendesk sign-ups specifically.

I just didn't want to keep maintaining this script if they find some other way to exploit Zendesk in the future, hence my nuclear approach.

[1]: https://gist.github.com/hampuskraft/780c8fbcc4042689153533ef...