With this plugin you can instantly block (or redirect) visitors, who's IP address is in an IP set of known offenders, from snooping around and look for vulnerabilities in your site. The IP Sets are maintained by (commercial) companies and are regularly (some real time) updated to hold the latest offenders. These IP sets can have millions of know offenders!

And you can tap into this massive 'community' maintained resource and block all offending bots / hackers / malware / spammers on your site.