Email – How can you block more than 5,000 addresses with a web email app?

How do you block more than 5,000 addresses (> = 5000 addresses / domains) with a web email app?

Why for which request?

Save e-mail addresses from a "subscription bomb". Accounts were targeted and registered for thousands of newsletters, sales catalogs, etc. The inboxes are flooded daily, so there is no practical solution. Years of e-mail addresses would have to be abandoned.

Probably no solutions

  • A small manually entered blacklist feature due to the time required.
  • I have already blocked a cleaned cleanup list (only unique addresses / domains) as a text file. The list size seems to rejuvenate, which is why I think it's solvable, not infinite.
  • Functions with Bayesian ratings and / or machine learning. The attacker only logged in to receive tons of emails. A lot of normal companies that should not be labeled.

Possible solutions

  • I've just discovered Sieve scripts, though everyone has them, and their boundaries are not well documented.
  • Add-ins / plugins. I'm trying to figure out how to use plugins too, but have not yet figured out how to do this.

More information
– The reason I just have to figure out how to block 5000 is that the attack was big, but it was finite.