Wordfence - Comprehensive security plugin for WordPress.
iThemes Security - Security plugin that provides over 30+ ways to secure and protect your WordPress site.
Virusdie - All-in-One cloud-based, simple, powerful and gorgeous website security tools built for everyone.
Sucuri - Website Protection, Malware Removal, and Blacklist Prevention
Acunetix - Audit your website security and web applications for SQL injection, Cross site scripting and other...
WebARX - Website Protection, Managed Website Security & Website Monitoring