How else can I stop spam registrations / bots?

[Emediate]

I have this morning had to disable new registrations from our large 150,000+ user community due to what must be a bot registering spam accounts.

I have all the usual registration features in place (captcha etc).

But in the last 24 hours I've had over 2500 registrations. Every one is passing the Spam Defence score (1), and they are activating their email. They are all using different IP addresses from across the world so an IP ban is out of the question.

I have all new registrations locked into a very limited use New Member user group that does not give them any access until they introduce themselves, but I made the mistake of allowing this group to still have limited PM access. Unfortunately as they learned they couldn't spam our board they have started PM'ing random members with dating site links, each account up to their 5 PM a day limit.

I have now of course disabled sending PMs from this new group, but it's not stopping the hundreds of registrations still coming per hour.

I've manually banned all the accounts, but what else can I do?

The only consistency I can see is a random female name followed by 4 numerals.

 

Edited January 18, 2021 by Emediate

[CoffeeCake]

Based on your screenshot, it looks like it's a bunch of temporary e-mail addresses. You might want to look into something like these applications:

 

 

[SUBRTX]

I found these are the most popular email service so I DISABLED the others