Somebody at 184.108.40.206 was trying at a very high speed to brute-force /wp-login.php for one site on my server. The downside was that there was no /wp-login.php or any part of wordpress to brute-force, but that did not seem to deter the attacker. A temporary firewall rule now rejects all attempts. Update 2014-07-31: Next load of attempts from 220.127.116.11. And looking back in the logs shows other similar attempts.