We're aware of the spam attack hitting mastodon.social right now and our full moderation and DevOps teams are on the case mitigating any way we can (incl. switching to approval-mode registrations)
All of the spam accounts have been suspended, reports queue cleared, IPs and e-mail domains used in the spam wave banned. We're continuing to monitor the situation and analyzing the pattern.
@gh0sti that would be a bad idea. If anything the opposite should be done. Literally all (I really mean literally---every single one) of the spammer signup attempts I have ever had to my instance in 6 years has been from a gmail, yahoo or outlook address.