OSSEC HIDS : An Open Source Host-based Intrusion Detection System
OSSEC HIDS performs log analysis, integrity checking, rootkit detection, time-based alerting and active response. In addition to its IDS functionality, it is commonly used as a SEM/SIM solution. Because of its powerful log analysis engine, ISPs, universities and data centers are running OSSEC HIDS to monitor and analyze their firewalls, IDSs, web servers and authentication logs.