Foren / Cotonti / General / Russian spam?

Anybody getting a LOT of spam accounts from guys with mail.ru as their e-mail. I was banning IPs because I figured it was an isolated incident. Today I have over 40 junk accounts. On the same thought is there a way to disallow registration with a mail.ru e-mail? Banlist says it doesn't support wildcards for e-mail.

Just wanted to know if it was a Cotonti thing, or just my site personally.