# Security Onion is a free Linux distribution for threat hunting and monitoring > Security Onion is a free and open Linux distribution that bundles tools for threat hunting, enterprise security monitoring, and log management, with a web console and cloud marketplace images. **Security-Onion-Solutions/securityonion** — Security Onion is a free and open platform for threat hunting, enterprise security monitoring, and log management. It includes our own interfaces for alerting, dashboards, hunting, PCAP, detections, and case management. It also includes other tools such as osquery, CyberChef, Elasticsearch, Logstash, Kibana, Suricata, and Zeek. - Repository: https://github.com/Security-Onion-Solutions/securityonion - Website: https://securityonion.net - Stars: 4,903 · Forks: 678 - Language: Shell - License: NOASSERTION - Published: 2026-09-23 · Updated: 2026-09-23 · Language: en - Canonical page: https://hysenlabs.com/projects/security-onion-solutions-securityonion ## What Security Onion is Security Onion is a free and open Linux distribution built for threat hunting, enterprise security monitoring, and log management. The README says it includes a suite of tools that work together to give visibility into network and host activity. Rather than being a single program, it is a curated collection of open source security tools assembled so they share data and present results in one place. Organizations deploy it to watch what is happening across their systems and to investigate signs of trouble. The project positions the distribution as the foundation for a security operations capability that scales from a single sensor to a multi-node grid. The bundled tools talk to each other through shared storage and messaging, which is what lets a single search return both an IDS alert and the packet that triggered it. ## Core features in the box The README lists the main capabilities that ship with the distribution. The Security Onion Console, or SOC, is a unified web interface for analyzing security events and managing the grid. The Elastic Stack backs powerful search with Elasticsearch. Intrusion detection covers network based IDS with Suricata and host based monitoring with Elastic Fleet. Network metadata is generated in detail by Zeek or Suricata, and full packet capture retains and analyzes raw network traffic with Suricata PCAP. Together these give defenders both summaries and the raw evidence behind them, so a single alert can be explored from overview down to packets. ## Security Onion Pro and cloud deployment For larger organizations, Security Onion Pro adds features aimed at scale and efficiency. The README names Onion AI, which brings AI driven insights to speed up analysis and investigations, and enterprise features that add tools and integrations for enterprise grade operations. Beyond the open distribution, the project is available as ready to deploy images in the AWS, Azure, and Google Cloud marketplaces, so a team can stand up a sensor or manager without building from scratch. More detail on Pro sits on the vendor's product page, while the core distribution remains free to use. Running in a cloud marketplace also means the sizing and networking steps are documented for that platform, lowering the barrier for a first deployment. ## Getting started and resources The README points new users to a download ISO, a hardware guide for requirements, installation instructions, and release notes, presented as a short goal to resource table. Documentation lives at the project docs site, with a dedicated FAQ, community discussions and support, and official training. Because the distribution ties many tools together, the docs are the place to learn how the pieces fit and how to tune a deployment for a given network. The contribution guide invites outside help through a CONTRIBUTING file, and the project welcomes pull requests from the community. ## Licensing and project background The README states that Security Onion is licensed under the terms found in the repository's LICENSE file, and the project describes itself as free and open. The distribution is built and maintained by Security Onion Solutions, and the README closes with a note that it was built by that team. The open license and public documentation mean a team can inspect how the bundle behaves, while paid Pro features and cloud images offer a supported path for organizations that want vendor backing. Community support channels complement the official training and docs for day to day questions. Because the LICENSE file governs the release, users can audit the exact terms rather than relying on a marketing summary, and the community edition keeps the same core tools as the paid options. ## How the pieces fit for monitoring In practice a Security Onion deployment collects network and host data, enriches it with metadata and IDS alerts, and stores it in the Elastic Stack so analysts can search and visualize it from the SOC. Full packet capture means an alert can be traced back to the exact bytes on the wire, while Zeek metadata gives structured records of connections and protocols. That combination supports both live monitoring and later threat hunting, where an analyst follows a hunch across logs and packets. The README's feature list reflects this pipeline rather than a single standalone tool, which is why the project is described as a distribution instead of an application. ## Conclusion Security Onion is a free and open Linux distribution that packages threat hunting, enterprise security monitoring, and log management into one deployable system. Its feature set spans a unified web console, the Elastic Stack for search, Suricata and Elastic Fleet for intrusion detection, Zeek or Suricata for network metadata, and full packet capture for raw evidence. Security Onion Pro adds AI assisted analysis and enterprise features, and the distribution is available in the major cloud marketplaces. With open licensing, public documentation, and community support, it gives defenders a ready made base for watching network and host activity. ## FAQ ### Is Security Onion a siem tool? Security Onion is described in its README as a free and open Linux distribution for threat hunting, enterprise security monitoring, and log management, bundling tools such as the Security Onion Console, the Elastic Stack, and Suricata. It provides monitoring and visibility rather than being a single SIEM product, though the included console and search stack support a security operations workflow. ### What is Security Onion used for? According to the README, Security Onion is used for threat hunting, enterprise security monitoring, and log management. It gives visibility into network and host activity through a web console, the Elastic Stack, intrusion detection with Suricata, network metadata from Zeek or Suricata, and full packet capture. ### Is Security Onion a free software? Yes. The README states Security Onion is a free and open Linux distribution and that it is licensed under the terms in the repository LICENSE file, so the project is released as free and open source software. ## Sources - [Issues](https://github.com/Security-Onion-Solutions/securityonion/issues) - [Project website](https://securityonion.net) - [README](https://github.com/Security-Onion-Solutions/securityonion/blob/3/main/README.md) - [Releases](https://github.com/Security-Onion-Solutions/securityonion/releases) - [Security-Onion-Solutions/securityonion on GitHub](https://github.com/Security-Onion-Solutions/securityonion) --- Hysen Labs editorial analysis, written from the project's own repository and release notes. Cite the canonical page: https://hysenlabs.com/projects/security-onion-solutions-securityonion