Top 9 Open Source SIEM Tools for 2025

Organizations face cyber threats daily, making SIEM systems essential for real-time threat detection and response. Open source SIEM tools offer free features for businesses with limited budgets.
By SentinelOne November 24, 2024

Cyber attacks have increased by 30% since last year, which is why security teams at most organizations are scrambling to find and build stronger security strategies. In just the second quarter of 2024, organizations faced an average of 1,636 cyber attacks per week, a staggering number that challenged even the most prepared security teams.

Your team needs tools that allow them to gather, analyze, and respond to security data from across all your networks in real time. And to achieve that they need Security Information and Event Management systems, popularly known as SIEM. Because of all the insights into potential vulnerabilities and threats that they offer, organizations using SIEM have expressed great confidence in their security, with 60% reporting higher levels of confidence in their security posture. In contrast, only 46% of organizations without an SIEM system felt secure, highlighting the value of SIEM platforms.

SIEM platforms can be costly. But, the good news is that you opt for open-source SIEM solutions if you are seeking to improve your security without significant financial investment. This article lists some of the top open-source SIEM tools available, highlighting their features and benefits.

What is Open-Source SIEM?

Open-source SIEMs are basically free platforms that pack all the best features of any SIEM tool at no cost. These are cybersecurity software that collect, analyze, and manage security data from various sources within an organization’s IT infrastructure, like applications, servers, and network devices, enabling real-time threat detection and incident response.

Unlike proprietary SIEM tools, open-source options are typically free to use. They allow organizations to customize and adapt the software to their specific needs without incurring licensing fees.

Also, they perform essential functions such as event correlation, alerting, and data visualization, which are important for maintaining a robust security posture.

Need for Open-Source SIEM tools

As these open-source SIEM tools are generally free to use, they are highly attractive for organizations working with limited budgets. Businesses can implement essential security measures without the financial burden of licensing fees associated with commercial products.

Just because they are free does not mean they lack quality features. The tools listed below offer a range of powerful capabilities, such as log management, intrusion detection, event correlation, and compliance reporting, making them suitable for various cybersecurity needs.

Another key advantage is the transparency that open-source software provides. Organizations can conduct thorough security audits with access to the underlying source code. This access enables teams to identify and address potential vulnerabilities proactively. Its visibility also allows for customized adjustments, so organizations can tailor features and functionalities to meet their unique requirements.

Moreover, open-source SIEM tools are often designed to integrate seamlessly with other security solutions, enhancing overall effectiveness. For example, platforms like Wazuh and Security Onion can work alongside other open-source tools, such as Suricata and OSSEC, to provide comprehensive security coverage, helping organizations strengthen their defenses through an interconnected approach.

Open-Source SIEM Tools Landscape in 2025

We’ll learn some of the best open-source SIEM tools based on peer-review platforms such as Gartner Peer Insights or PeerSpot.

#1 Cisco Systems SIEM

Cisco’s SIEM solution consolidates log and event data from multiple network devices, enabling organizations to identify potential threats and respond effectively. It operates by capturing and interpreting events across the network, structuring this information for future reference and action.

In the event of a security incident, the system aggregates relevant data to assess the threat’s severity and facilitates timely responses.

Features:

  • Centralized data aggregation: The tool collects logs and event data from various sources such as applications, databases, servers, and firewalls.
  • Real-time threat detection: It utilizes predefined rules and machine learning to filter and prioritize alerts, focusing on significant security issues.
  • Automated responses: Cisco integrates with Security Orchestration, Automation, and Response (SOAR) technologies to automate incident responses based on customized policies.
  • Enhanced visibility: The solution provides insights into security events by correlating data with threat intelligence feeds, improving the ability to monitor and respond to threats

Know more about customer and technical reviews along with ratings of Cisco Systems SIEM on Gartner and G2

#2 LogRhythm SIEM

LogRhythm SIEM is a security solution designed to enhance threat detection and response capabilities within organizations. It integrates various security functions such as log management, security analytics, and endpoint monitoring into a unified platform, making it easier for security teams to manage and respond to threats effectively.

Features:

  • Continuous monitoring: LogRhythm employs Automated Machine Analytics to provide real-time intelligence on security events, allowing teams to prioritize threats based on their risk levels.
  • Threat lifecycle management: This feature enables end-to-end threat management, allowing organizations to detect, respond to, and recover from threats within a single platform.
  • High-performance log management: The platform can process terabytes of log data daily, offering immediate access for investigations. It supports both structured and unstructured searches.
  • Network and endpoint monitoring: LogRhythm provides detailed insights into network and endpoint activities through built-in forensic sensors.

Check LogRhythm reviews and ratings to get an informed opinion about their capabilities.

#3 IBMQRadar SIEM

IBM QRadar SIEM aggregates and analyzes security data from across an organization’s IT infrastructure. It collects logs and network flows from various sources, processes this information, and applies correlation rules to detect potential security threats. These capabilities enable security teams to prioritize alerts based on the severity of threats.

Features:

  • Centralized visibility: The platform offers a unified view of security events across on-premises and cloud environments, allowing security teams to monitor activities from a single dashboard.
  • Extensive integration capabilities: With over 700 pre-built integrations, QRadar can seamlessly connect with existing security tools and data sources.
  • Advanced threat detection: Artificial intelligence (AI) and machine learning enhance alert prioritization and incident correlation.

Confirm IBMQRadar SIEM credibility and its offerings by looking at the reviews on Gartner Peer Insights.

#4 Trellix Enterprise Security Manager

Trellix is an open-source SIEM solution for detecting, responding to, and managing security threats. It integrates various security functions into a cohesive platform, providing comprehensive visibility across systems, networks, applications, and cloud environments.

Features:

  • Threat intelligence: Trellix integrates external threat data and reputation feeds with internal system activity, offering a holistic view of the security landscape.
  • Monitoring and analysis: The platform allows for continuous monitoring of activities, enabling security teams to quickly prioritize, investigate, and respond to potential threats.
  • Automated compliance management: It supports numerous global regulations and frameworks such as GDPR, HIPAA, and more, by automating compliance tasks, which reduces the manual effort required for audits.

Check out Peerspot reviews to see what users have to say about Trellix Enterprise Security Manager.

#5 Rapid7 InsightIDR

Rapid7 InsightIDR is a cloud-native SIEM solution that integrates incident detection and response capabilities with advanced analytics and threat intelligence. It is designed to provide organizations with comprehensive visibility into their security posture, enabling the identification of potential threats.

Features:

  • User Behavior Analytics (UBA): InsightIDR employs UBA to establish baselines for normal user behavior, allowing it to detect anomalies such as compromised accounts or lateral movement within the network.
  • Deception technology: It includes deception capabilities, such as honeypots and honey users, designed to lure attackers and reveal their tactics early in the attack chain.
  • Automated security response: The solution offers automated workflows for incident containment, enabling security teams to take immediate actions such as quarantining infected endpoints or suspending compromised user accounts.

Explore the feedback and ratings to get further insights into Rapid7 InsightIDR’s capabilities.

#6 Microsoft Sentinel

Microsoft Sentinel is a SIEM security open-source solution designed to provide security analytics and threat detection across an organization’s digital landscape. Formerly known as Azure Sentinel, it uses artificial intelligence and automation to enhance security operations, enabling organizations to manage and respond to cyber threats.

Features:

  • Active threat detection: The platform provides tools for proactive threat hunting, allowing security analysts to search for indicators of compromise across their data sources before alerts are triggered.
  • Threat intelligence integration: It integrates Microsoft’s threat intelligence feeds while allowing users to incorporate their threat intelligence sources.
  • Data connectors: Microsoft Sentinel offers a wide array of built-in data connectors that facilitate the integration of security data from various sources, including Microsoft products, third-party services, and cloud environments.

Get Microsoft Sentinel’s review and rating on Gartner Peer Insights.

#7 Google Chronicle SIEM

Google Chronicle SIEM provides organizations with advanced capabilities for threat detection, investigation, and response. It employs Google’s robust infrastructure to analyze vast amounts of security telemetry data, enabling security teams to enhance their operational efficiency in combating cyber threats.

Features:

  • Detection engine: The Chronicle’s Detection Engine automates the process of searching for security issues across ingested data. Users can set up rules to trigger alerts when potential threats are identified, streamlining the incident response process.
  • Advanced analytics: The tool analyzes security data in real time using machine learning. This capability allows organizations to quickly detect indicators of compromise (IoCs) and respond to potential threats before they escalate.
  • Data ingestion and normalization: Google Chronicle can ingest a wide variety of security telemetry types through multiple methods, including lightweight forwarders and ingestion APIs.

Check out the Google Chronicle SIEM’s reviews on Gartner Peer Insights.

#8 McAfee ESM

McAfee Enterprise Security Manager (ESM) is an open-source SIEM tool that helps detect, investigate, and respond to security threats. It combines advanced analytics, real-time event correlation, and extensive integration capabilities to provide actionable intelligence for security operations.

Features:

  • Log management and analysis: The solution includes the McAfee Enterprise Log Manager, which automates log collection and analysis across all types of logs.
  • Global threat intelligence: McAfee ESM integrates with McAfee Global Threat Intelligence (GTI), enhancing its ability to detect known threats and vulnerabilities.
  • Advanced correlation engine: It utilizes a robust correlation engine that analyzes security events in real time. This feature enables the swift identification of potential threats by correlating data from various sources, allowing security teams to prioritize incidents.

Look at ratings of McAfee ESM on Peerspot

#9 Splunk

Splunk SIEM, specifically through its Splunk Enterprise Security (ES) offering, is a solution designed to help organizations detect, investigate, and respond to security threats in real time. It provides comprehensive visibility into security events across various environments.

Features:

  • Comprehensive dashboards: Splunk ES provides customizable dashboards that offer insights into security metrics, incident trends, and system performance.
  • Advanced threat detection: The software uses machine learning and user behavior analytics (UBA) to detect anomalies and potential threats by establishing baselines for normal behavior.
  • Real-time data analysis: It enables continuous monitoring and analysis of security data from a multitude of sources, allowing security teams to identify and respond to threats as they occur.

Learn more about Splunk’s offerings, features, and verified user feedback users are giving about Splunk.

How do you Choose the Right Open-Source SIEM Tool?

Selecting the right open-source SIEM tool can be challenging for many users; however, we’ve highlighted key factors to guide your decision.

1. Evaluate your Security Needs

When choosing a SIEM solution, start by defining your main objectives—whether that’s threat detection, compliance, log management, or a combination of these. Let these goals steer your selection process. For organizations operating in complex multi-cloud environments or managing high log volumes, scalability is crucial. Smaller setups, however, may find that a more lightweight SIEM with core features suffices.

2. Analyze Features and Capabilities

Evaluate the SIEM’s features and capabilities, as each tool varies in focus. For instance, some SIEMs excel in log management, while others emphasize real-time monitoring and analytics. Get a solution that has key features like log management, reporting, and threat detection and response.

3. Evaluate Integration and Compatibility

A good SIEM should ingest data from all critical sources, including servers, network devices, endpoints, and cloud services. Also, confirm its compatibility with other security tools like firewalls, antivirus software, and intrusion detection systems (IDS). The right SIEM should fit seamlessly into your existing security ecosystem.

API compatibility is also important, as it allows customization to fit unique workflows and integration into broader security operations.

4. Consider Ease of Use and Community Support

Prioritize tools with an intuitive interface and an active community presence. Look for resources such as forums, GitHub issues, extensive documentation, training videos, and an active user base. Some tools also offer paid support options, which can be beneficial if professional assistance is needed.

Introducing SentinelOne as a SIEM Solution

SentinelOne’s Singularity™ SIEM is next-generation security, advancing on sophisticated threat detection along with AI-driven automation and empowering organizations with real-time and rapid responses. Contrary to a typical SIEM tool, it integrates with and protects multi-cloud and hybrid environments. It ensures complete visibility for activities network, endpoints, and workload.

SentinelOne shines in terms of threat correlation, utilizing machine learning to identify anomalies and predict potential attack vectors. The ingestion of large volumes of log data does not affect its performance, allowing for constant monitoring in the most demanding environments. Singularity™ SIEM also simplifies compliance with automated reporting and customizable dashboards that are tailored to meet industry standards such as GDPR, HIPAA, and PCI DSS.

With endpoint security, behavior analytics, and proactive remediation integrated into its SIEM solution, SentinelOne provides an ideal approach to modern security challenges for organizations seeking to improve their threat detection and incident response capabilities. Ingest first-party data and third-party data from any source with 10GB per day included for free. Replace brittle SOAR workflows with hyper-automation. You can gain enterprise-wide, autonomous protection with human governance with SentinelOne’s SIEM capabilities.

Conclusion

From the article, we’ve learned that open-source SIEM tools are great for organizations wanting to boost their cybersecurity without spending too much money. These tools can be customized and scaled to fit specific needs, providing strong threat detection, real-time monitoring, and better visibility into security issues.

As an organization, you can assess your security needs by looking for important features like threat detection and log management and ensure the tool can integrate well with their existing systems. Tools like Microsoft Sentinel, Google Chronicle SIEM, and Rapid7 InsightIDR are great options to explore, offering a range of features from advanced analytics and API integrations to real-time data monitoring. It’s also important to choose a tool that is easy to use, can grow with the organization, and offers good support. For a more comprehensive, AI-driven approach, consider SentinelOne’s Singularity SIEM, which provides automated processes, real-time threat detection, and enhanced security insights.

Schedule a demo today to experience how SentinelOne Singularity SIEM can improve your organization’s security.

FAQs

1. Which technology is an open-source SIEM system?

These are some of the popular open-source SIEM systems, including AlienVault OSSIM, Splunk, Rapid7 InsightIDR, and Elastic Stack. These platforms provide essential features for security monitoring, event logging, and threat detection, allowing organizations to customize and manage their security infrastructure effectively.

2. What are the benefits of using open-source SIEM tools

Open-source SIEM tools offer cost-effectiveness, transparency, and customizability. They allow organizations to modify the source code to fit specific needs. Also, they can be integrated with various other security tools to enhance overall security posture.

3. Can open-source SIEM tools be scaled for large organizations?

Yes, many open-source SIEM tools, like Microsoft Sentinel and LogRhythm SIEM, are designed to scale effectively for large organizations. They can handle vast amounts of data and integrate with cloud services, making them suitable for enterprises with extensive security monitoring needs.

4. What’s the difference between open-source and licensed SIEM tools?

Open-source SIEM tools are typically free to use and allow for customization, while licensed tools often come with comprehensive support, advanced features, and user-friendly interfaces. Licensed solutions may also provide quicker implementation but at a higher cost compared to their open-source counterparts.

5. How do I choose the right open-source SIEM tool for my organization?

To choose the right open-source SIEM tool, assess your organization’s specific needs regarding scalability, compliance requirements, ease of integration, and available technical expertise. Consider the level of community support and the quality of documentation for each tool to ensure successful implementation.

6. What features should I prioritize in the open-source SIEM tool?

Prioritize features such as event correlation, real-time monitoring, alerting capabilities, compliance reporting, and integration options with existing security tools. In addition, consider user-friendliness and the ability to handle large volumes of data effectively.

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