I've been using a catch-all on all my custom domains for as long as I've had a custom domain and it's worked great.
However, about 2 weeks back my business custom domain started creating loads of aliases that were used to send me spam (all related to finance/accounts, the message would say I owe a vendor money.) I disabled the catch-all so that they spam would stop, but I'd still like to use it if possible (via the auto create rules).
Does anyone have a regex for Simplelogin that I can use to help combat this issue? Or is this there not much that I can do?
I can provide a list of the aliases that were created if it helps?
Auto-create is just a regex-rule-defined catch-all. I don't know how SL handles it when there is no defined match (could reject them), but the only way you could use it to combat spam is if the spam was following a specific structure, or you were happy to pre-define unique strings where everything that matches (or not) goes into the abyss (or is auto-trashed).
If they don't follow some repeated structure then no. You can provide a list of anonymised aliases and we'll see...
Looks like they're just spamming at the domain owner. If they're coming from the same sender, block the sender, otherwise you could try and use auto-create and designate an abnormal string like .*zdz.* — so that every alias that includes the string "zdz" somewhere will work.
Be sure to test it out at the bottom of the rule page.