Verisys!

OSSEC is an Open Source Host-based Intrusion Detection System. It performs log analysis, file integrity checking, policy monitoring, rootkit detection, real-time alerting and active response.

NNT Change Tracker Gen7 uses either an agent-based or agentless architecture – the choice is yours. After initial discovery, Gen7 scans your devices and compares them to a standard policy. The policy applied will either be user defined or based on an industry standard such as the Center for Internet Security (CIS). Policies can be automatically assigned based on the device type or priority via a centrally managed console.

Open Source Tripwire software is a security and data integrity tool useful for monitoring and alerting on specific file change(s) on a range of systems.