🩺 Vitals
- 🟢 Last active: 2026-07-16
- 📦 Latest release: 3.1.0-20260528 (2026-05-28)
- 🐞 Open issues: 90
- 🌟 Stars: 4.7k
What do these metrics mean?
- Last active: when code was last pushed, as of our last check. The dot is green when that was recent, grey otherwise. A long gap can mean a tool is finished and stable, not only unmaintained.
- Latest release: the most recent tagged, packaged version the maintainers published. Not every healthy project tags releases.
- Open issues: unresolved reports and requests. A high number is normal for a popular project and is not a warning on its own.
- Stars: how many people bookmarked the project on its forge. A rough popularity signal, not a measure of quality.
🏗️ Profile
- Official: securityonionsolutions.com
- Source: github.com/Security-Onion-Solutions/securityonion
- License: ELv2 (Source-Available, not OSI Open Source)
- Deployment: ISO · Bare Metal | Docker
- Data Model: Index-based (Elasticsearch) + raw PCAP
- Jurisdiction: USA 🇺🇸 (Security Onion Solutions, LLC, Georgia)
- Compliance (SaaS): N/A (no hosted offering)
- Compliance (Self-Hosted): Self-Hosted (User Managed)
- Complexity: High (4/5) - Distributed grid (Elasticsearch, Suricata, Zeek); sizing and tuning required
- Maintenance: High (4/5) - Ruleset tuning, index/storage management, grid upgrades
- Enterprise Ready: High (4/5) - SSO, encryption at rest, FIPS/STIG, API (all Pro tier)
1. The Executive Summary
What is it? Security Onion is a network security monitoring and threat hunting platform. It bundles the standard open blue-team stack (Suricata for intrusion detection, Zeek for network metadata, the Elastic Stack for search and dashboards, and full packet capture) into a single self-hostable "grid" that a SOC deploys to watch its own network traffic. In business terms, it gives a security team a complete view of what is happening on the network, from raw packets to correlated alerts, without sending any of it to a vendor cloud.
Unlike endpoint-focused Wazuh, which streams telemetry from agents installed on each machine, Security Onion watches the network itself. The two are complementary layers, not substitutes. What separates Security Onion from the fully open tools in the hub is its licence: the platform is source-available under the Elastic License 2.0, not OSI open source, and several of its most security-relevant controls (single sign-on and encryption at rest among them) are reserved for the paid Pro tier.
The Strategic Verdict:
- 🔴 For Teams Needing SSO or Disk Encryption on Day One: Caution. The free tier authenticates locally and does not encrypt data at rest; OIDC SSO and LUKS encryption require Pro. For regulated environments, budget for Pro from the start rather than treating the free tier as production-ready.
- 🟢 For SOCs and Airgapped or Government Environments: Strong Buy. Security Onion is the most complete self-hostable NSM platform available, runs fully airgapped, and keeps every packet of sensitive network telemetry on infrastructure you control. STIG hardening (Pro) maps directly to US public-sector requirements.
2. The "Hidden" Costs (TCO Analysis)
| Cost Component | Corelight (Commercial) | Security Onion (Self-Hosted) |
|---|---|---|
| Network Sensors | Per-sensor appliance licensing | $0 (free tier), or Pro subscription |
| Packet Capture and Retention | Appliance storage tiers | Cost of your own disk / storage |
| SSO and Encryption at Rest | Included | Pro tier |
3. The "Day 2" Reality Check
🚀 Deployment & Operations
- Installation: Deployed from a self-contained ISO or onto a supported Linux host, in standalone, distributed-grid, or airgapped topologies. A production grid runs Elasticsearch, Suricata, Zeek, and the Security Onion Console across sized nodes.
- Scalability: Scales from a single evaluation box to a multi-node grid with dedicated search and forward nodes. Managing several grids from one console (Manager of Managers) is a Pro feature.
🛡️ Security & Governance (Risk Assessment)
- Jurisdiction & Geopolitics (USA 🇺🇸): Security Onion Solutions, LLC is a US company (Evans, Georgia), so the corporate entity sits under US jurisdiction and the CLOUD Act. Because the platform is deployed entirely on user infrastructure with no vendor cloud, and supports fully airgapped operation, the data itself stays outside any vendor or foreign reach. Sovereignty here is a property of the deployment, not of the licence.
- The Compliance Shift and Enterprise Tax: There is no SaaS, so there are no vendor certifications to inherit; 100% of infrastructure security, patching, and monitoring is yours. The platform provides compliance-relevant controls, but the ones auditors ask about are Pro: FIPS 140 cryptographic baselines, STIG operating-system hardening for CAT 1 findings, RBAC, and data-at-rest encryption. Read the free tier as a capable monitoring platform, not a compliance-ready one; regulated deployments need Pro.
- License Risk (The ELv2 Ceiling): Security Onion is source-available under the Elastic License 2.0, not OSI open source. For internal enterprise use this is largely academic, since you can deploy, modify, and airgap it freely. The hard ceiling is commercial: ELv2 forbids offering the software as a hosted or managed service to third parties, which blocks MSSPs from building a managed Security Onion offering without a vendor agreement. Governance is also concentrated in a single US LLC with no independent foundation, so the free-versus-Pro line and the licence terms are the vendor's to move.
4. Market Landscape
🏢 Proprietary Incumbents
- Corelight: The commercial network-detection platform built by Zeek's own creators. It packages the same Zeek engine that sits at the core of Security Onion into supported enterprise appliances; organizations run Security Onion to get Zeek and Suricata visibility without per-sensor appliance licensing.
- Splunk: The SIEM and log-analytics incumbent for security operations. Its per-GB ingestion pricing scales adversely with packet and log volume; teams adopt Security Onion to hunt across full network telemetry on storage they own rather than metering every gigabyte.
🤝 Open Source Ecosystem
- Wazuh: The open-source, endpoint-focused XDR and SIEM; the complementary layer to Security Onion's network view. Endpoint plus network is the standard pairing for full SOC coverage.
- Arkime: Open-source, large-scale full packet capture and indexing (formerly Moloch). Teams pair or substitute it with Security Onion when the priority is long-retention PCAP search at volume.