Security Onion is a free and open Linux distribution for threat hunting, enterprise security monitoring, and log management.
The tool addresses the need for comprehensive network and host visibility by bundling detection, analysis, and investigation capabilities into a single platform. It combines network-based intrusion detection through Suricata, host-based monitoring via Elastic Fleet, and network metadata generation from Zeek or Suricata. The Security Onion Console provides a unified web interface for analyzing security events, while the Elastic Stack powers search and log management. Full packet capture retention enables raw network traffic analysis when needed.
Organizations should choose this tool if they need an integrated security monitoring platform that combines multiple detection and analysis functions without requiring separate tool integration. It suits enterprises and security teams operating their own infrastructure, particularly those wanting to avoid vendor lock-in through its open-source foundation. The platform is available as a downloadable ISO for on-premises deployment and through cloud marketplaces for AWS, Azure, and Google Cloud. A commercial Pro tier offers AI-driven analysis and enterprise-grade features for organizations requiring advanced capabilities at scale.
The project maintains active development with regular updates documented in release notes. Documentation is comprehensive and includes hardware requirements guidance, installation instructions, and a frequently asked questions section. The team provides official training resources and maintains community support channels for user questions and discussions. Contributions are welcomed through established guidelines, indicating ongoing community engagement with the codebase.
