TL;DR, What is Security Onion?

Security Onion is a unified, open-source platform that integrates network monitoring, intrusion detection, threat hunting, and log management into a single cohesive system.

Security operations teams struggle with expensive, fragmented security tools that require multiple interfaces and specialized expertise, creating visibility gaps and operational complexity. Security Onion eliminates these pain points by providing enterprise-grade capabilities at no cost, while offering the flexibility to scale from small lab environments to large enterprise deployments.

The platform integrates industry-standard tools like Suricata, Zeek, Elasticsearch, and Logstash in a pre-integrated environment, making comprehensive network security monitoring accessible without the complexity of managing disparate solutions.

Developers created Security Onion as an open-source project, and the platform has evolved into a mature solution that serves both production security operations and educational purposes, helping address the cybersecurity skills gap through hands-on learning opportunities.

Detect active cloud threats

Learn how Wiz Defend detects active threats using runtime signals and cloud context—so you can respond faster and with precision.

Work Email*

First Name*

Last Name*

Country

Phone Number*

Company*

Keep me updated about Wiz product releases, industry news, and events (You can unsubscribe at any time)

Subscribe me to the Wiz blog digest emails

Submit

For information about how Wiz handles your personal data, please see our Privacy Policy.

Your work email here

Get a demo

At‑a‑Glance

• GitHub: https://github.com/Security-Onion-Solutions/securityonion

• License: Elastic License 2.0 (ELv2)

• Primary Language: Python

• Stars: 3.9k ⭐

• Last Release: August 2025

• Topics/Tags: SIEM, network security monitoring, intrusion detection, threat hunting, log management, SOC

Common use cases

1. Security Operations Center (SOC) and 24/7 Monitoring: Organizations deploy Security Onion as their primary network security monitoring platform to provide continuous visibility into network traffic and security events. SOC analysts use the unified console to investigate alerts generated by the intrusion detection system, correlate events across multiple data sources, and perform real-time threat analysis.

The platform's customizable dashboards enable effective shift handovers and management reporting, while the case management system supports structured incident response processes. The comprehensive logging and audit trails make Security Onion valuable for compliance reporting and demonstrating security due diligence to auditors and regulators.

2. Advanced Threat Hunting and APT Detection: Security teams leverage Security Onion's threat-hunting platform capabilities to proactively search for indicators of advanced persistent threats, insider threats, and sophisticated attack campaigns that may evade traditional detection methods. Hunters use the platform's advanced analytics, Zeek logs analysis, and historical data retention to identify unusual network behaviors, lateral movement patterns, and command-and-control communications.

The integration with threat intelligence feeds and the MITRE ATT&CK Navigator framework helps analysts map observed behaviors to known attack techniques and develop custom detection rules for emerging threats.

3. Network Forensics and Incident Investigation: When security incidents occur, investigators use Security Onion's comprehensive data collection and analysis capabilities to perform detailed forensic analysis. The platform's full packet capture functionality allows analysts to reconstruct attack sequences, examine malicious payloads, and understand attacker techniques.

Combined with network metadata from Zeek and timeline analysis capabilities, investigators can create detailed incident reports, determine the scope of compromise, and gather evidence for legal proceedings or internal disciplinary actions.

4. Compliance Monitoring and Regulatory Reporting: Organizations in regulated industries use Security Onion to demonstrate compliance with security requirements such as PCI DSS, HIPAA, and SOX. The platform's comprehensive logging, long-term data retention, and detailed audit trails provide evidence of security monitoring and incident response capabilities.

5. Cybersecurity Training and Skill Development: Educational institutions, training organizations, and security teams use Security Onion as a hands-on learning platform for developing practical cybersecurity skills. Students and professionals gain experience with industry-standard tools including Elastic Stack security components, practice incident response procedures using real-world datasets, and develop threat-hunting methodologies in a safe laboratory environment.

The platform's comprehensive documentation and active community make Security Onion ideal for self-paced learning and certification preparation programs.

How does Security Onion work?

Security Onion operates through a sophisticated data pipeline that captures, processes, and analyzes network traffic and endpoint telemetry in real time. Network traffic enters through monitoring interfaces where AF-PACKET captures packets, which are then simultaneously processed by multiple analysis engines. The collected data flows through Elastic Agents to Logstash for parsing and normalization, then queues in Redis before final indexing in Elasticsearch. The Security Onion Console provides analysts with a unified interface for investigating alerts, hunting threats, and managing cases.

• Multi-Engine Analysis: Security Onion performs intrusion detection and metadata extraction, Zeek generates detailed protocol logs and behavioral analysis, Stenographer captures full packet data for forensics, and Strelka analyzes files for malware detection.

• Data Processing Pipeline: Logstash performs parsing, normalization, and enrichment of logs before queuing in Redis, followed by a secondary Logstash pipeline that forwards processed data to Elasticsearch for indexing.

• Endpoint Visibility: Elastic Agents deployed on endpoints collect system logs, Sysmon events, and other telemetry to provide comprehensive host-level monitoring.

• Scalable Architecture: The modular design supports multiple deployment types from simple import nodes to distributed grids with specialized roles (managers, sensors, search nodes) for enterprise scalability.

• Unified Analysis Interface: The Security Onion Console integrates alert management, dashboards, threat-hunting capabilities, case management, and PCAP retrieval in a single analyst workstation.

How to Prepare for a Cloud Cyberattack: An Actionable Incident Response Plan Template

A quickstart guide to creating a robust incident response plan - designed specifically for companies with cloud-based deployments.

Your work email here

Download template

Core Capabilities

1. Unified Security Operations Console (SOC): Security Onion provides a comprehensive web-based interface that consolidates all security operations into a single pane of glass, eliminating the need for analysts to switch between multiple tools. The console includes advanced querying capabilities using the Onion Query Language (OQL), customizable dashboards for real-time monitoring, timeline analysis for incident reconstruction, and AI-powered alert summaries that help prioritize investigations.

The unified approach reduces cognitive load on security analysts while improving investigation efficiency through seamless pivoting between different data types, network metadata, and analysis tools. The interface supports collaborative workflows with integrated case management, allowing teams to escalate alerts directly into structured investigations with proper documentation and audit trails.

2. Multi-Engine Network Detection and Monitoring: The platform integrates multiple complementary detection engines to provide comprehensive network visibility and threat-detection capabilities. Suricata serves as both an intrusion detection system and network security monitoring platform, generating real-time alerts and network metadata.

Zeek provides deep protocol analysis and behavioral detection, creating detailed logs for protocols including HTTP, DNS, SSH, and TLS, which enable sophisticated threat hunting and forensic analysis. Stenographer captures and indexes full packet data for complete forensic reconstruction, while Strelka analyzes files extracted from network traffic for malware indicators.

The multi-engine approach ensures threats are detected through various methodologies, reducing false negatives and providing rich contextual information for security investigations across the entire network infrastructure.

3. Scalable Grid Architecture for Enterprise Deployment: Security Onion supports distributed deployments through a sophisticated grid architecture, enabling organizations to scale from standalone installations to enterprise-wide distributed networks with specialized node roles. Manager nodes provide centralized administration and web interfaces, search nodes handle data storage and Elastic Stack security operations, sensor nodes perform traffic monitoring and Zeek logs analysis, and heavy nodes combine multiple functions for smaller deployments.

SaltStack-based configuration management ensures consistent deployment and management across all grid members, automatically handling load balancing, data replication, and service dependencies. The architecture supports high-availability configurations and can accommodate growing data volumes and geographical distribution requirements while maintaining centralized management and visibility.

4. Integrated Case Management and Incident Response Workflow: The platform includes comprehensive case management capabilities that transform security events into structured investigations with proper tracking and collaboration features. Cases support collaborative investigation workflows with assignee management, threaded comments, file attachments, observable tracking, and integration with external threat intelligence sources for context enrichment.

Analysts can escalate events directly from alerts, hunt results, or dashboard views, with the system automatically populating case data with relevant context including network metadata, packet captures, and related indicators. The workflow supports standard incident response methodologies with customizable playbooks and provides detailed audit trails for compliance reporting, making Security Onion suitable for formal security operations programs and regulatory requirements.

5. Advanced Threat Hunting and Proactive Analytics Platform: Security Onion provides sophisticated threat-hunting capabilities designed for proactive threat discovery and advanced persistent threat detection. The Hunt interface offers pre-built queries focused on suspicious behaviors and attack patterns, while customizable dashboards provide trend analysis and overview capabilities for ongoing monitoring.

Both interfaces support the powerful Onion Query Language for complex data analysis, including statistical functions, grouping, sorting, and temporal analysis across network security monitoring data. Integration with external tools like MITRE ATT&CK Navigator helps analysts map observed behaviors to known attack techniques, while Jupyter notebook integration enables advanced statistical analysis and custom analytics development for specialized hunting methodologies and threat intelligence correlation.

Limitations

1. Resource Intensive Infrastructure Requirements: Security Onion requires significant computational resources and storage capacity to effectively process and analyze network traffic at scale. The multi-engine architecture with Suricata, Zeek, Elasticsearch, and packet capture capabilities demands substantial CPU, memory, and disk I/O resources. Organizations with high-bandwidth networks may need dedicated hardware clusters to handle the data processing load, making Security Onion potentially cost-prohibitive for smaller organizations with limited IT budgets or infrastructure capabilities.

2. Steep Learning Curve and Technical Expertise: The platform requires significant cybersecurity expertise and technical knowledge to deploy, configure, and operate effectively. Users need familiarity with network protocols, log analysis, threat-hunting methodologies, and the various integrated tools. The complexity of the open-source SIEM components and advanced querying capabilities mean organizations may need specialized training or experienced personnel, which can be challenging for teams with limited security operations experience or resources.

3. Network-Centric Focus with Limited Endpoint Visibility: While excellent for network security monitoring and intrusion detection system capabilities, Security Onion primarily focuses on network-based detection and may provide limited visibility into endpoint-specific threats, application-layer attacks, or host-based indicators of compromise. Organizations requiring comprehensive endpoint detection and response (EDR) capabilities may need to integrate additional tools or solutions to achieve complete security coverage across their infrastructure.

4. Complex Multi-Node Deployment and Management: The distributed grid architecture, while powerful for scalability, introduces significant complexity in deployment and ongoing management. Organizations must carefully plan node roles, network connectivity, certificate management, and data flow between distributed components. Configuration errors or network issues can impact the entire grid's functionality, requiring specialized knowledge for troubleshooting and maintenance of the Elastic Stack security infrastructure.

5. Limited Commercial Support and Vendor Accountability: As an open-source platform, Security Onion relies primarily on community support and documentation rather than commercial vendor support with guaranteed response times and service level agreements. Organizations operating in regulated industries or those requiring immediate technical support may find the community-based support model insufficient for critical security operations, potentially necessitating internal expertise development or third-party consulting arrangements.

Getting Started

Step 1: Download Security Onion ISO

Download the latest ISO from the official page: https://docs.securityonion.net/en/2.4/download.html.

Step 2: Create bootable media or VM

• Burn the ISO to a USB stick or

• Mount it in a virtual machine and boot your target system.

Step 3: Install Security Onion

Follow the on-screen prompts to complete the installation process.

Step 4: Run setup wizard after reboot

After rebooting, log in and run the setup wizard via the terminal: so-setup

Step 5: Access Security Onion web interface

Use the web interface (https://<HOSTNAME>) to access dashboards, alerts, and begin monitoring.

Security Onion vs. Alternatives

FAQs