Open-source Darktrace alternatives

Suricata is an engine for network intrusion detection (IDS), intrusion prevention (IPS) and network security monitoring (NSM), developed by the Open Information Security Foundation and the Suricata community. It inspects network traffic to detect threats, can block them when run inline as an intrusion prevention system, and supports network security monitoring and threat hunting.

The README stresses why the software is built so carefully. It processes mostly untrusted input and often sits directly reachable by an attacker, so a crash in IPS mode could knock a network offline, a compromise in passive mode could expose confidential data, and missed detections could hide an intrusion. For that reason contributions go through a long QA process that includes GitHub CI checks, peer review and private QA runs with build tests, static analysis, runtime analysis with valgrind and sanitizers, and regression tests.

Suricata is written in C and licensed under GPL-2.0. The project provides a user guide, an installation guide, a developer guide, a bug tracker and a user support forum for administrators who deploy it on their own networks.

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.