Granted, that many requests from a single host would be suspicious, but if the attacker has resources (i.e. botnet) he can spread those requests over many hosts.
If you run your own server, you could lay traps. Like, letting file2ban monitor logs for requests for e.g. the infamous info.php and block that IP.
If you absolutely have to store sensitive information on your webserver (data exchange, backup, etc) at least put it into a Truecrypt container and upload that one instead.