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Security Onion

Security Information and Event Mgmt. (SIEM)

Open Source
Free Tier
Self-hosted
OpenMSP Score
79
70
Reddit Impact Score
Github Score
171M
4KStars
658Forks
18KCommits
OtherLicense
Jul 6, 2026Last commit

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Security Onion is a free and open platform built by defenders for defenders. It provides comprehensive network and host visibility, intrusion detection, log management, and case management capabilities. Security Onion is deployed within all major industry verticals, governments, and Fortune 500 enterprises worldwide. Key Components: • Network Visibility: Signature-based detection via Suricata, protocol metadata and file extraction using Zeek or Suricata, full packet capture using Stenographer or Suricata • Host Visibility: Elastic Agent providing data collection, live queries via osquery, and centralized management using Elastic Fleet • Intrusion Detection: Network Intrusion Detection System (NIDS) alerts and OpenCanary honeypots • Security Onion Console (SOC): Custom interfaces for alerts, dashboards, threat hunting, case management, and grid management Current Version: Security Onion 2.4.140 (released March 2025) • Security Onion 2.4.150 celebrating over 2 million downloads • New AI Summary feature for enhanced threat analysis • Zeek 7 support with additional protocol analysis (QUIC, HTTP2, OpenVPN, IPSEC) • Enhanced API capabilities for Security Onion Pro customers • Local IP lookup features for better environment mapping Recent Enhancements: • Base OS migration and improved container architecture • Integration with Elastic 8.17.3 • Enhanced detection capabilities with Sigma and YARA rules • Improved case management and investigation workflows • Real-time alerting and automated response capabilities Security Onion integrates best-of-breed open source tools including Suricata, Zeek, Elasticsearch, Logstash, Kibana, CyberChef, NetworkMiner, and many others. It enables organizations to monitor north/south and east/west traffic, detect lateral movement, and provide comprehensive endpoint telemetry for complete security visibility.
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Key Features

Free and open source network security monitoring

Comprehensive network security monitoring platform combining multiple open source tools in a unified distribution, providing enterprise-grade capabilities without licensing costs or vendor lock-in.

Full packet capture and network forensics

Complete network traffic capture and storage capabilities enable detailed forensic analysis of security incidents, providing evidence trail and supporting post-incident investigation activities.

Intrusion detection with Suricata and Snort

Multiple intrusion detection engines including Suricata and Snort provide redundant threat detection capabilities with community and commercial rulesets for comprehensive network monitoring.

Elasticsearch and Kibana for log analysis

Integrated Elasticsearch cluster with Kibana dashboards enables scalable log analysis, visualization, and correlation across diverse security data sources with customizable reporting capabilities.

Network metadata analysis with Zeek

Zeek network analysis framework provides detailed network metadata extraction and protocol analysis, enabling behavioral analysis and network forensics beyond traditional signature-based detection.

Integrated security orchestration with TheHive

Optional integration with TheHive incident response platform enables case management, workflow automation, and collaborative investigation capabilities for structured incident response processes.

Pros and Cons

Pros

All-in-one solution

Comprehensive security monitoring in one distribution

Open source

Fully open source and free

Tool integration

Pre-integrated with numerous security tools

Network visibility

Strong network visibility and monitoring

Active community

Active community and development

Cons

Resource intensive

Requires significant hardware resources

Complex deployment

Complex deployment and configuration

Linux knowledge

Requires Linux expertise

Limited scalability

Challenges scaling for very large environments

Feature Comparison

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Frequently Asked Questions

Getting Started

OpenMSP is The MSP Knowledge Hub & Community Platform designed specifically for Managed Service Providers seeking to optimize their technology stack, reduce vendor costs, and discover open-source alternatives. We combine a comprehensive vendor directory, open-source solution catalog, and integrated community discussions to help MSPs make informed decisions.
Yes, completely free. Browse vendors and tools, read comparisons, and join community discussions - no cost, no registration required. OpenMSP is community-supported and focused on empowering MSPs to reduce costs and improve operational efficiency through open-source technology.
We help MSPs identify cost-effective alternatives to expensive commercial solutions, provide transparent vendor information, and connect you with proven open-source alternatives. Our platform enables MSPs to make informed decisions about their technology investments.
No account required for browsing vendors, reading comparisons, or accessing community content. Creating a free account with SSO (Microsoft, Google, or Slack) allows you to participate in discussions and save your favorite tools.

Platform Information

OpenMSP is currently community-supported. We focus on providing value to the MSP community first. Any future monetization will keep the core platform free for MSPs while maintaining our independence and commitment to unbiased information.
We focus exclusively on MSP needs with transparent vendor information and open-source alternatives. No vendor partnerships or sponsored listings - just honest, community-driven information to help MSPs make better technology decisions. Our biggest value is our community where MSPs help each other with questions, setup guidance, and sharing real-world experiences.
Our community of MSP professionals helps verify and update information. We also maintain direct research on tools and vendors to ensure accuracy. Community members can report outdated information, and we work to keep everything current.
OpenMSP was founded by Michael Assraf, who has extensive experience in the MSP industry and product leadership. As the former CEO & Founder of Vicarius, Michael grew a startup from $0 to $9M ARR with 500+ customers and deep experience working with MSPs, partners, and fundraising. OpenMSP represents his commitment to empowering the MSP community through better technology decisions and cost optimization.

Open-Source Tools & Alternatives

We assess tools based on active development, community size, documentation quality, production deployments by MSPs, and available support options. Tools must meet strict criteria for reliability and enterprise readiness.
Many open-source projects offer multiple support options including community forums, commercial support from vendors, professional services, and our community discussions where experienced MSPs share implementation guidance.