What is Security Onion used for?

Security Onion is a free Linux platform for threat hunting, network and host security monitoring and log management, with a unified web console. It is a good fit for security operations center monitoring, threat hunting across network traffic and incident investigation with full packet capture.

Is Security Onion open source?

Yes. Security Onion is open source under a custom licence. Its source code is on GitHub at Security-Onion-Solutions/securityonion and is written mainly in Shell.

Is Security Onion free?

Yes. Security Onion is open source, so the software itself is free to use under the terms of its own licence.

Can I self-host Security Onion?

Yes. Security Onion can be self-hosted on your own server or infrastructure; there is no official hosted version.

What is Security Onion an alternative to?

Security Onion is an open-source alternative to Splunk, Darktrace, Microsoft Defender and Sumo Logic. Other open-source alternatives to Splunk include Wazuh and Graylog.

Is Security Onion actively maintained?

Yes. The most recent commit to Security Onion was on 2 October 2026, and the latest release is 3.3.0-20260911, published on 11 September 2026. The project has 4.9k stars on GitHub.

Security Onion: open-source alternative to Splunk, Darktrace

About Security Onion

Security Onion is a no-cost, open Linux distribution built for threat hunting, security monitoring across an enterprise, and log management. It bundles a suite of tools designed to work together so defenders get visibility into both network and host activity from a single platform.

The Security Onion Console is a unified web interface for analyzing events and managing the deployment, with its own tools for alerting, dashboards, hunting, packet capture, detections and case management. Underneath it uses the Elastic Stack for search, Suricata for network intrusion detection, Elastic Fleet for host monitoring, Zeek for network metadata and other tools such as osquery and CyberChef. The installer and configuration are largely shell scripts.

The repository license appears as 'Other' on GitHub. Security Onion is deployed on your own hardware or virtual machines, either standalone or as a distributed grid. It suits security operations centers, incident responders and blue teams that want an integrated, open alternative to commercial monitoring platforms.

Key features

Unified Security Onion Console web interface
Network intrusion detection with Suricata
Network metadata from Zeek
Elastic Stack search and dashboards
Case management and threat hunting
Packet capture and detections

Good fit for

→Security operations center monitoring
→Threat hunting across network traffic
→Incident investigation with full packet capture

Built with: Shell
Tags: security; threat-hunting; ids; siem; log-management; suricata; zeek; blue-team

Security Onion: questions and answers

What is Security Onion used for?: Security Onion is a free Linux platform for threat hunting, network and host security monitoring and log management, with a unified web console. It is a good fit for security operations center monitoring, threat hunting across network traffic and incident investigation with full packet capture.
Is Security Onion open source?: Yes. Security Onion is open source under a custom licence. Its source code is on GitHub at Security-Onion-Solutions/securityonion and is written mainly in Shell.
Is Security Onion free?: Yes. Security Onion is open source, so the software itself is free to use under the terms of its own licence.
Can I self-host Security Onion?: Yes. Security Onion can be self-hosted on your own server or infrastructure; there is no official hosted version.
What is Security Onion an alternative to?: Security Onion is an open-source alternative to Splunk, Darktrace, Microsoft Defender and Sumo Logic. Other open-source alternatives to Splunk include Wazuh and Graylog.
Is Security Onion actively maintained?: Yes. The most recent commit to Security Onion was on 2 October 2026, and the latest release is 3.3.0-20260911, published on 11 September 2026. The project has 4.9k stars on GitHub.