Detect and neutralize malicious programs running on your PC.
BS Editor: OSSEC is a scalable, multi-platform, open source Host-based Intrusion Detection System (HIDS). It has a powerful correlation and analysis engine, integrating log analysis, file integrity checking, Windows registry monitoring, centralized policy enforcement, rootkit detection, real-time alerting and active response.

It runs on most operating systems, including Linux, OpenBSD, FreeBSD, MacOS, Solaris and Windows. you can free download OSSEC HIDS Agent Manager 2.5 now.