Wordfence by mmaunder is an enterprise firewall and anti-virus plugin for WordPress websites.
Wordfence is a premium plugin, you need to get an API key to start protecting your site. Wordfence offer a free 5 day trial, charges are then $9.95 per month.
Wordfence:
Scans core files, themes and plugins against repository versions.
See how files have changed. Optionally repair changed files.
Scans for signatures of over 44,000 known malware variants.
Continuously scans for known dangerous malware and phishing URL’s in all your comments, posts and files.
Scans for heuristics of backdoors, trojans and suspicious code.
Checks the strength of all user and admin passwords.
Monitor for unauthorized DNS changes.
Monitor disk space.
Includes a firewall to block fake Googlebots, malicious scans from hackers and botnets.
Configure rate limiting based on different types of traffic.
Choose whether you want to block or throttle users and robots who break your rules.
Includes login security to lock out brute force hacks and to stop WordPress from revealing info useful to a hacker.
See all your traffic in real-time, including robots, humans, 404 errors, logins and logouts and who is consuming most of your content.
A real-time view of all traffic including crawlers, scrapers and shows in depth data on each hit including city level location.
Download: http://wordpress.org/extend/plugins/wordfence/
