Open-source DIY SIEM (Wazuh / Security Onion)
A self-operated open-source SIEM stack for log collection, endpoint telemetry, detections, and investigations.
Free
Software can be free, but infrastructure, storage, tuning, and staff time are material operating costs.
- Lowest software cost and highest deployment control
- Good learning path for hands-on security teams
- Can support compliance logging and basic detection use cases
- Requires real engineering time to deploy, tune, and maintain
- No built-in 24/7 analyst coverage unless you add a service provider