Open-source SentinelOne alternatives

Wazuh is a free and open-source platform for threat prevention, detection and response. It protects workloads across on-premises, virtualized, containerized and cloud environments and combines XDR and SIEM functions in one product. The code is written mainly in C++.

The solution consists of an endpoint security agent installed on monitored systems and a management server that collects and analyzes the agents' data. It is integrated with the Wazuh Indexer, which offers a search engine and visualization for navigating security alerts. Agents scan for malware, rootkits and suspicious anomalies, read system and application logs, and monitor files for changes to content, permissions, ownership and attributes.

Rule-based analysis of collected logs, including data received from network devices through syslog, helps surface misconfigurations, policy violations and attempted or successful attacks. Repository topics also cover vulnerability detection, configuration assessment, incident response and compliance such as PCI DSS. The repository lists its license as 'Other', so review the license files for the exact terms.

Falco is a cloud native runtime security tool for Linux. It detects and alerts on abnormal behavior and potential security threats in real time. At its core it is a kernel monitoring and detection agent that watches events such as system calls and evaluates them against custom rules.

Falco can enrich events with metadata from the container runtime and from Kubernetes, and the collected events can be analyzed off-host in SIEM or data lake systems. The project is split across repositories in the falcosecurity organization: the main repo holds the Falco binary, while others hold the core libraries and kernel drivers, the official ruleset, and plugins that extend detection beyond syscalls and container events.

Falco was originally created by Sysdig and is a graduated project of the Cloud Native Computing Foundation, used in production by various organizations. It is written in C++ and released under the Apache-2.0 license, with a change log and detailed documentation on falco.org. Topics in the repository mention eBPF-based collection.

OSSEC is a host-based intrusion detection system (HIDS) that watches individual servers and endpoints for signs of compromise. Its README describes it as a platform that brings together HIDS, log monitoring and SIM/SIEM capabilities in one open-source package.

The project's description lists log analysis, file integrity checking, policy monitoring, rootkit detection, real-time alerting and active response. Those capabilities support compliance work as well as detection, and the repository's topics refer to PCI DSS and NIST 800-53. Stable releases and documentation are published on ossec.net, with community help on Slack and Discord.

OSSEC is written in C and licensed under GPL-2.0. It bundles a modified zlib and a small part of OpenSSL, along with the cJSON library. Atomicorp hosts the annual OSSEC conference, and the development version is available through a simple git clone.

Security Onion is a no-cost, open Linux distribution built for threat hunting, security monitoring across an enterprise, and log management. It bundles a suite of tools designed to work together so defenders get visibility into both network and host activity from a single platform.

The Security Onion Console is a unified web interface for analyzing events and managing the deployment, with its own tools for alerting, dashboards, hunting, packet capture, detections and case management. Underneath it uses the Elastic Stack for search, Suricata for network intrusion detection, Elastic Fleet for host monitoring, Zeek for network metadata and other tools such as osquery and CyberChef. The installer and configuration are largely shell scripts.

The repository license appears as 'Other' on GitHub. Security Onion is deployed on your own hardware or virtual machines, either standalone or as a distributed grid. It suits security operations centers, incident responders and blue teams that want an integrated, open alternative to commercial monitoring platforms.