It performs log analysis, integrity checking, Windows registry monitoring, rootkit detection, time-based alerting, and active response.

It provides intrusion detection for most operating systems, including Linux, OpenBSD, FreeBSD, OS X, Solaris and Windows.

OSSEC has a centralized, cross-platform architecture allowing multiple systems to be easily monitored and managed.

In May 2009, Trend Micro acquired Third Brigade and the OSSEC project, with promises to keep it open source and free.

In 2018, Trend released the domain name and source code to the OSSEC Foundation.