The Best Open Source SIEM Tools Of 2024

Learning to drive in a high-speed racing car might not be the wisest choice for beginners. Similarly, investing in a full-fledged SIEM tool may not be feasible if you’re just entering the cybersecurity business. Start your cyber defense journey with an open source SIEM tool that can protect your systems without breaking the bank. We’ve put together a our detailed guide on the top five solutions so you can understand their benefits, capabilities and drawbacks.

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Like any other purchase, evaluating the best open source SIEM tools can be challenging. With limitless considerations and features to compare, we’ve created this guide to simplify your software selection process.

Best Open Source SIEM Tools

Our analysts at SelectHub have carefully shortlisted the best free open source SIEM tools for your reference.

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Wazuh

Wazuh is a free enterprise-ready open source SIEM tool that evolved from OSSEC. It offers vulnerability detection, security log analysis, configuration assessment and regulatory compliance capabilities. You can implement the software on Linux operating systems, and it supports on-premise, cloud-based and hybrid deployment methods.

While a free version is available, there’s also a paid option with a hosted cloud platform that offers an attractive UI, straightforward setup and open-source threat intelligence feeds.

Suitable For

• IT security managers
• Site reliability engineers
• Software developers
• General managers
• Administrators

Supported OS

• Linux

Top Benefits

• Analyze Security Logs: Active endpoint monitoring and auditing help protect IT infrastructure and meet regulatory compliance. Collect, aggregate and analyze security event data to detect irregularities and indicators of compromise (IoC). Get contextual information and reduce response time by expediting investigations.
• Monitor File Integrity: You can receive comprehensive alerts from file integrity monitoring (FMI) when it detects system changes. Expand these alerts and get a detailed summary of changes on the dashboard.
• Examine System Inventory: Identify system assets and evaluate patch management efficacy by collecting system data, including installed software details, ports, network interfaces and OS information from monitoring endpoints. Generate inventory reports to identify unwanted apps, services, malicious artifacts and processes.
• Supervise Containers: Monitor signs of unexpected security incidents across containers and get real-time alerts. Protect workloads at both container and infrastructure levels.
• Install in Offline Mode: You can install Wazuh even without an active internet connection. Set up and configure central components like the indexer, server and dashboard in an all-in-one deployment on the same host. You can also deploy each component in separate hosts.

Primary Features

• Security Configuration Assessment (SCA): The platform helps identify security flaws and misconfigurations in your systems. It uses CIS benchmarks to scan your systems for efficiently detecting and remediating deviations from best practices. Scan tests provide three possible results: passed, failed and not applicable.
• Active Response: Wazuh can stop running processes, block network connections and delete malicious software or files to automate incident response. It provides stateful or stateless active response capabilities.
• Rootkits Detection: Rootcheck analysis helps scan systems and detect rootkits at the user space and kernel level. The platform uses signatures of known trojans and rootkits to generate alerts on anomalies.
• Regulatory Compliance: It helps comply with regulatory frameworks like GDPR, TSC SOC2, HIPAA, NIST 800-53 and PCI DSS and offers tools to detect policy violations.
• Alerts and Notifications: The system generates real-time notifications and alerts quickly after anomaly detection to reduce response time.

Limitations

• It doesn’t offer timely updates for UI/UX improvements.
• The platform lacks external data ingestion features.
• It doesn’t provide real-time monitoring for Unix systems.

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AlienVault OSSIM

OSSIM (open source security information management) by AlienVault is a leading free open source SIEM tool. It also has an enterprise-grade paid version, USM Anywhere, with more advanced features. You can use the free version on a single server, but upgrading it to the paid version allows scaling to additional servers.

The platform comprises security frameworks like OSSEC, Nagios, Snort and OpenVAS. It features event collection, correlation, normalization and a threat intelligence feed called open threat exchange (OTX).

Suitable For

• IT security and risk managers
• Consultants
• Industry analysts
• Tech writers
• Administrators

Supported OS

• Windows
• Linux

Top Benefits

• Discover Asset Information and Inventory: Scan and identify assets on the network to determine primary information such as IP addresses, operating systems and MAC addresses. Asset visibility helps you better understand your inventory status.
• Manage Alarms: Get alerts on any event with a risk value of one or higher. You can also use filters to search for specific alarms.
• Access Threat Intelligence: Open Threat Exchange (OTX), a threat intelligence community, offers community-powered actionable insights into bad actors and emerging threat trends.
• Monitor USB Devices: Capture and monitor USB device events on Windows systems through a host intrusion detection system (HIDS). You can view information about HIDS events, including serial number, driver, size and file system.
• Manage Policies: Create better policies to control and manage event processing based on your workflow needs.

Primary Features

• Intrusion Detection System: You can monitor hosts and networks to detect policy violations and malicious activities. It also helps to identify hacking attempts, anomalies and possible intrusions.
• Behavioral Monitoring: OSSIM analyzes behavioral patterns to identify deviations from the predefined standard. This lets you detect unknown threats and policy violations by authorized devices.
• Event Correlation: You can correlate and analyze log and event data across the system for better incident response.
• Vulnerability Assessment: Schedule vulnerability scans for IT assets based on vulnerability signature databases. It helps identify insecure configurations and unpatched software across the organization.
• Reporting: The platform generates real-time notifications and reports, including alarm, compliance, ticket status and availability reports. USM, the paid version, offers customized and flexible reporting capabilities.

Limitations

• It lacks consistent product documentation.
• The platform doesn’t provide a separate log server.
• The customer support response time is slow.

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Mozilla Defense Platform (MozDef)

Mozilla defense platform is a set of free microservices used as an open source SIEM platform. It’s built on third-party tools like Meteor and Kibana.

It offers capabilities like event correlation and security alerts and aims to automate incident response. You can also customize alert preferences with Python plugins. The system offers a self-hosted deployment model but doesn’t include mobile support.

Suitable For

• IT managers
• Analysts
• Consultants
• Tech writers
• Administrators

Supported OS

• Mac
• Linux

Top Benefits

• Achieve Scalable Indexing: Integrate with Elasticsearch to get scalable indexing and efficient searching of JSON documents.
• Integrate Third-Party Apps: Connect with third-party apps, including log shippers and data sources like Beaver, NXlog, Logstash, GuardDuty and CloudTrail, to improve your distributed environment. You can set them up on multiple platforms or hosts.
• Harness Transit Data: Python plugins let you manipulate data in transit. You can use these plugins to customize alert workflows and enrichment streams.
• Analyze Authentication Events: A GeoModel extension helps compare authentication events to identify potential malicious activities. It features two core components: an analysis engine and an alert emitter.
• Enhance Visibility: Monitor key performance indicators of your security system’s health and status, including cluster health and events per second. You can also track each elastic search node with the hot threads section.

Primary Features

• Event Management: It offers various event management modules like event indexing, storage, searching and archiving. You can index event fields, store events for log management and use Kibana for event searching.
• Incident Handling: This integrated module allows several responders to collaborate on security events. Use a VERIS classification system to tag incidents with metadata, helping aggregate incident metrics.
• Event Enrichment: Create plugins and incorporate customized metadata into event data to ensure effective event correlation.
• Regulatory Compliance: MozDef implements test driver security (TDS) to verify networks, services and systems against compliance regulations in real time and assist you in reporting.
• Dashboards: You can use interactive and customizable dashboards to quickly access actionable insights into trends, event data and other vital metrics. It offers 3D visual representations and service-oriented visualizations.

Limitations

• It doesn’t offer efficient customer support.
• The platform lacks integration with proprietary systems.
• It doesn’t have consistent product documentation.

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Graylog Open

Graylog Open is a free, open source SIEM platform offering centralized log management capabilities. It collects, stores, enhances and analyzes security events and log data.

Top features include dashboards, advanced searches, fault tolerance, content packs and graylog sidecar. It also provides a dashboard to display real-time security monitoring data, vital metrics and trends on a single page.

Suitable For

• IT security managers
• Network analysts
• Consultants
• Healthcare providers
• Administrators

Supported OS

• Linux

Top Benefits

• Optimize Indexing: Manage several Elasticsearch indices for analysis and search optimization, ensuring higher speed and lower resource consumption. You can use index sets with different analyzers, mappings and replication settings.
• Simplify Configurations: Handle flexible configurations for both third-party log collectors and Graylog collectors within one centralized interface. Tag systems help maintain a consistent configuration across all hosts.
• Streamline Task Execution: You can pull particular time ranges from Graylog data anywhere to analyze issues at any given time. Build queries and perform tasks like troubleshooting, conducting forensics, responding to breaches and analyzing user behavior.
• Monitor Geolocations: A geolocation processor helps track and visualize geolocations of field assets by extracting IP addresses from logs. It can even display maps in latitude and longitude format.
• Expand Functionality: The Graylog marketplace offers a centralized repository that includes a GELF library, content packs, plug-ins and external systems.

Primary Features

• Search Parameters: This feature helps build and execute queries. You can initiate standard analysis using several input parameters and display results in different formats, including charts and graphs. Share complex queries with data aggregation and visualization.
• Fault Tolerance: It features a load balancer with numerous servers ingesting logs and provides additional interfaces. You can ensure zero data loss by configuring Elasticsearch and MongoDB databases. Additionally, a message journal stores data on a disk to avoid damage by power losses.
• Content Packs: Built-in inputs, streams and extractors ensure you collect and identify logs correctly before processing them. It converts logs into searchable and readable files.
• Lookup Tables: You can overwrite existing fields or create new message fields by mapping and translating field values.
• Role-Based Access Control: This capability helps assign proper access levels to policies and job roles to different users. Administrators can assign roles (event creator, notification creator and event definition creator) and access levels (manager, viewer and owner).

Limitations

• It doesn’t offer timely updates for UI/UX enhancements.
• The platform lacks external data ingestion features.
• It doesn’t provide real-time monitoring for Unix systems.

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Prelude OSS

Prelude OSS is the free open source SIEM version of the vendor’s enterprise-grade software. It supports multiple log formats and can easily integrate with third-party tools like Suricata, OSSEC and Snort. The IDMEF format lets you use intrusion detection system (IDS) data.

It offers capabilities like data monitoring, legal inquiry, alerting, reporting and third-party integrations.

Suitable For

• Defense staff
• IT security managers
• Analysts
• Security consultants
• IT managers
• Administrators

Supported OS

• Linux
• Mac

Top Benefits

• Ensure Seamless Log Compatibility: Analyze all types of logs, including IDS, VPNs, firewalls, databases, monitoring systems, routers, POP/SMTP servers, web servers, FTB servers, honeypots, vulnerability scanners and more. The log analyzer allows you to analyze log information from these hosts to detect malicious activities.
• Automate Ticketing Processes: Integrate with advanced ticketing systems to automatically update, create and browse public tickets.
• Track Agent Heartbeats: Heartbeats are periodic signals generated by agents to provide updates on their status, like connecting or terminating the connection. Get continuous ticketing agent heartbeat updates on a dedicated tab in real time.
• Improve Data Retention: Store all collected data from supported databases, including MySQL, SQLite and PostgreSQL, in a centralized database. You can design data retention policies using scheduled crontab jobs as well.
• Acquire Native Support: Get active native support for the most used systems, including Samhain, Snort, AuditD, OSSEC, Linux-PAM, Samhain, Pam, Nepenthes, SanCP and NuFW.

Primary Features

• Data Monitoring: Analysts can prioritize and customize events based on criteria like agent information, event severity and the extent of damage. You can also define assets containing values linked to various IDMEF fields.
• Data Classification and Filtering: This feature enriches data with information like the classification of addresses in IPv4 or IPv6. To refine data analysis, you can use different filter types, including thresholding, limitation and IDMEF event fields.
• Reporting: It offers real-time data visualization and generates customized, actionable reports. The output formats are IDMEF XML, email, database and flat logfile.
• Legal Inquiry: Prelude OSS offers access to legal inquiry tools like Whois, Ping, Nmap, Traceroute and more.
• Alerting: This capability helps you detect threats quickly by generating real-time alerts upon identifying suspicious activities. The alerting menu has three sections — alerts, threats (displaying the nature of hazards) and agents (providing agent and heartbeat details).

Limitations

• Centralized logging could be a single point of failure.
• It has protocol analysis vulnerabilities.

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Open Source SIEM vs. Enterprise-Grade SIEM

Open Source SIEM	Enterprise-Grade SIEM
It’s mostly free or has minimal software licensing costs. Support, maintenance and customization may cost extra.	They come with monthly or yearly subscription costs. The licensing fee covers software updates, maintenance and support.
It provides basic beginner-level SIEM capabilities, including log monitoring and event data collection and analysis.	It offers a wide range of professional and advanced features like UEBA, behavior analysis, advanced threat detection and compliance reporting.
You can customize these tools by adding and modifying the code and integrating it with other modules to suit your business requirements.	These tools also offer customization options but are designed with a broader feature set to suit all kinds of requirements, avoiding the need to extend or modify the code.
These tools have limitations when it comes to scalability and struggle with handling large amounts of data.	It’s highly scalable and capable of handling larger amounts of data per business needs.
You need to rely on community support and external consultants as they offer limited technical support.	Enterprise-grade SIEM vendors offer dedicated support platforms and troubleshooting, configuration and update assistance.

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Advantages & Limitations

Open source SIEM tools offer several enticing benefits in terms of simplicity, cost efficiency and flexibility. However, these advantages come hand in hand with certain limitations that you should carefully consider.

Advantages

• The tools are cost-effective and help save your business’ financial resources.
• You can use these systems as a stepping stone into the industry and enhance your skill set.
• Integrate with third-party solutions to achieve better cybersecurity protection.
• Suitable for small and medium organizations with limited cybersecurity budgets.

Limitations

• They don’t offer essential protection features like automation, visualization and in-depth visibility.
• You have to fix bugs and troubleshoot yourself, as assistance is hard to get.
• Several platforms cannot handle large cloud infrastructures, creating hindrances in your business operations.
• Most tools don’t offer comprehensive compliance support.
• Despite saving financial resources, these systems might end up taking much more time from your analysts and IT specialists.

FAQs

Is Wazuh a free solution?

Yes, Wazuh is a free enterprise-ready open source SIEM tool.

What are the cons of open source SIEM?

As mentioned above, open source SIEM tools require third-party integration and technical expertise to run smoothly. They don’t offer essential capabilities like storage management, in-depth analysis, compliance and more.

Is open source bad for security?

Open source tools offer their source code in the public domain for anyone to access, which isn’t inherently bad. However, malicious actors can exploit vulnerabilities present in the source code.

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Next Steps

While open source SIEM tools are great stepping stones, they aren’t enough for comprehensive log management and threat protection. As your company scales, you’ll eventually have to implement enterprise-grade SIEM platforms that offer advanced capabilities, technical support and quick deployment. That’s a big reason driving their dominance in the commercial market today.

If you’re ready to take the next step, check out our free comparison report on top SIEM tools. It offers valuable insights on top-rated vendors, software features and scorecards. You can also get reviews from actual selection processes to assist your software selection process.

Which open source SIEM tools have you used before? Do you find these tools valuable, and where do you think they fall short? Let us know in the comments below!