Top 8 Open Source SIEM Tools

What is SIEM?

A security information and event management (SIEM) system is the foundation of security processes in the modern security operations center (SOC). A SIEM saves security analysts the effort of monitoring many different systems. 

SIEM systems integrate with security tools, network monitoring tools, performance monitoring tools, critical servers and endpoints, and other IT systems. It aggregates the data, correlates it, analyzes it to discover anomalous or suspicious activity, and generates alerts when it identifies activity that might be a security incident.

SIEM Capabilities and Applications

SIEM solutions offer various capabilities that provide visibility into an entire corporate network of devices and apps. SIEM provides a centralized location for data collection and aggregation, including dashboards that offer insights into overall security and specific threats.

Threat intelligence

SIEM solutions offer insight into known indicators of compromise (IoC) and attacker tactics, techniques, and procedures (TTP). The tool uses several threat intelligence feeds, organizing and analyzing information on current and potential threats.

Threat detection

SIEM tools can detect threats in various locations, including emails, applications, cloud resources, endpoints, and external threat intelligence sources. Most SIEM solutions achieve threat detection by employing user and entity behavior analytics (UEBA). It helps monitor and detect abnormal behaviors indicating a threat, such as compromised accounts and lateral movement.

Alerting and investigation

After detecting a vulnerability, threat, suspicious behavior, or attack, SIEM tools create and send alerts to the relevant personnel for response and mitigation, supporting incident response operations. You can customize SIEM alerts to suit user needs and use managed rules to react almost in real-time to critical threats. Some solutions also offer workflow and case management with automatically created investigation instructions. 

Compliance and reporting

SIEM solutions support compliance and alert reporting to help organizations simplify compliance reporting. This functionality includes data dashboards that help monitor privileged user access and retain and organize event information. 

Top 8 Open Source SIEM Tools


Deployment model: on-premise

AlienVault OSSIM is an open source security solution that provides an intuitive platform for analyzing impending security risks. It provides various tools, including event correlation, vulnerability assessment, behavioral monitoring, and asset discovery.

OSSIM provides a complete SIEM by employing correlation capabilities, native log storage, and various open source projects, such as FProbe, Nagios, Munin, NFSen/NFDump, OSSEC, OpenVAS, PRADS, Suricata, TCPTrack, and Snort.


Deployment model: on-premise

Atomic Enterprise OSSEC is a cloud-based solution that offers various security and compliance capabilities. It helps organizations automate security processes in cloud, hybrid, and on-premise environments. OSSEC is based on an open source security framework that enables you to monitor and route logs and events to multiple SIEMs.

OSSEC offers intrusion detection, compliance reporting, file integrity monitoring, and policy management. It supports many compliance regulations, including JSIG, HIPAA, GDPR, and PCI DSS. Additionally, the platform lets you manage rules centrally and sends alerts to notify users about security changes to systems or files. 


Deployment model: on-premise

Wazuh is an open source platform that provides threat prevention, detection, and response capabilities. You can use Wazuh to protect workloads across on-premises, containerized, cloud-based, and virtualized environments.

Wazuh employs various mechanisms, including an endpoint security agent that monitors systems. It uses a management server to collect and analyze data collected by these agents. Additionally, Wazuh is fully integrated with the Elastic Stack, providing a search engine and data visualization tool that enables navigating through security alerts.

Apache Metron

Deployment model: on-premise

Apache Metron is a security framework for ingesting, processing, and storing diverse security data feeds at scale. It aims to enable organizations to detect and rapidly respond to cyber anomalies.

Here are key capabilities of this framework:

  • Security data lake or vault—the framework provides cost-effective, long-term storage for enriched telemetry data. You can leverage this data for feature engineering and discovery analytics, as well as search and query operational analytics.
  • Pluggable framework—Metron provides a rich set of parsers for common security data sources, including pcap, bro, netflow, snort, sourcefire, and fireye. It also offers a pluggable framework. You can use it to add new custom parsers for various new data sources and add new enrichment services for context. It lets you use pluggable extensions for threat intel feeds and customize your security dashboards.
  • Security application—the framework offers standard SIEM capabilities, including alerting, agents to ingest data sources, and threat intel framework. It also includes packet replay utilities and hunting services. 
  • Threat intelligence—the framework provides next-generation defense techniques that employ anomaly detection and machine learning algorithms in real-time while events stream in.


Deployment model: on-premise

SIEMonster is an enterprise-grade SIEM tool that combines several open source solutions into one centralized platform to provide real-time threat intelligence. Here are key features of SIEMonster

  • Human-based behavior—the tool can integrate with behavioral analysis tools to ensure recorded threats are true and minimize false positives.
  • Threat intelligence—the tool offers real-time threat intelligence, including open source or commercial feeds, to stop attacks as they occur.
  • Deep learning—the tool employs machine learning for analysis and to automatically kill attacks.

Prelude SIEM

Deployment model: on-premise

Prelude SIEM extends Prelude OSS to include an ergonomic interface and various security capabilities. It lets you continuously monitor your security posture for possible intrusion attempts and quickly analyze the cause of an alert. 

You can employ Prelude SIEM to correlate, search, investigate, and compare information to identify subtle threats and maintain the integrity of evidence. The tool lets you design and publish various formats of functional or technical reports.

Security Onion

Deployment model: on-premise

Security Onion is a Linux distribution for enterprise security monitoring (ESM) and intrusion detection. It offers network-based and host-based intrusion detection systems (IDS) and full packet capture (FPC), supporting various enterprise security monitoring and threat hunting responsibilities.

Here are key features:

  • Support for network-based intrusion detection systems (NIDS)—Security Onion collects network events from various tools, such as Suricata and Zeek, to provide complete coverage of the enterprise network.
  • Support for host-based intrusion detection system (HIDS)—Security Onion supports host-based event collection agents, such as Wazuh, Osquery, and Beats.
  • Static analysis (PCAP Import)—you can use Security Onion to import PCAP files for quick static analysis and case studies.


Deployment model: on-premise

Suricata is an open source engine for high-performance network IDS, IPS, and network security monitoring. It is owned by the Open Information Security Foundation (OISF), a non-profit organization. Suricata can store TLS certificates, log HTTP request logs, and extract files from flows and store them on disks.

Suricata uses automatic protocol detection for protocols like HTTP on all ports to apply the proper detection. It maintains integrations in JSON and YAML to support databases like Splunk and Elasticsearch, and supports multithreading natively.


In this article, I explained the basics of SIEM platforms and presented 10 open source SIEM solutions to get you started on your security data journey. While many of these SIEMs are not as fully-featured as commercial solutions, they provide more than enough functionality for small-to-medium organizations building their first SOC.

PKI-Security Engineer & security blogger at She is passionate about covering cybersecurity and Technology.

Leave a Reply