Open Source Intrusion Detection Systems

CrowdSec is a collaborative, distributed security engine designed for threat detection and infrastructure protection. It functions as an intrusion detection system that parses logs and network traffic to identify malicious patterns, utilizing a bucket-based threshold detection model to aggregate events and trigger alerts. The platform is built on a modular architecture that includes a centralized local API server for managing security signals and a relational database for persistent storage of remediation decisions. What distinguishes the project is its decoupled enforcement model, which offl

Wazuh is an integrated security platform that combines endpoint detection and response, security information and event management, and cloud workload protection. It functions as a centralized system for collecting telemetry, aggregating logs, and correlating events across distributed infrastructure to maintain security and integrity. The platform distinguishes itself through its active response orchestration, which allows for the automated execution of scripts on remote endpoints to neutralize threats in real time. It provides deep visibility into system activity through file integrity monito

Zeek is a network analysis framework and security monitoring tool that transforms raw network packets into high-level semantic logs. It functions as an application protocol analyzer and network intrusion detection system designed to extract meaning from network traffic and monitor for malicious activity. The system focuses on archiving network activity and maintaining historical records of application-layer state for forensic investigation and auditing. It utilizes a combination of modular protocol analyzers and customizable detection policies to perform deep semantic analysis of numerous app

Snort++

OSSEC v4.1.0

ModSecurity is an open-source web application firewall and security engine. It functions as an HTTP traffic inspector and intrusion detection system that filters incoming web requests and responses against a set of security rules to block threats and prevent attacks on web servers. The project provides a modular framework for implementing restrictive security policies and custom filtering logic. It identifies and blocks common injection attacks, such as cross-site scripting and SQL injection, while hardening web applications to reduce their overall attack surface. Its broader capabilities in

Falco is an eBPF runtime security monitor and cloud native detection engine that identifies abnormal behavior and security threats across hosts and containers. It functions as a Linux kernel event auditor, capturing system calls and kernel events in real-time to detect malicious activity. The system distinguishes itself through a rule-based threat detection model that evaluates system activity against a library of community-maintained rules and custom security definitions. It enriches raw kernel events with container and Kubernetes metadata to provide observability into isolated environments

OpenEDR is an endpoint detection and response platform designed to collect telemetry and monitor system activity to identify security breaches. It functions as a host-based intrusion detection system and telemetry collector, gathering detailed data on process, network, and file activity. The system includes a dockerized security stack that bundles search, logging, and visualization tools into containers for analyzing endpoint telemetry. It features a security event visualizer that maps process lineage and indexes logs to facilitate root-cause analysis of attacks. The platform provides capabi

Fail2ban is an intrusion prevention system that monitors system log files to detect malicious activity and automatically enforce security policies. By parsing log data in real time, the tool identifies patterns of unauthorized access or repeated authentication failures and responds by dynamically updating network access control lists to restrict offending sources. The software functions as a firewall automation tool that maintains stateful tracking of suspicious behavior across various network services. It utilizes a regex-driven pattern matching engine to identify specific attack signatures,

Security Onion is a security information and event management platform and network security monitoring suite. It functions as an intrusion detection system and a network traffic analysis tool designed to identify malicious activity and network intrusions through signature-based detection and host-based monitoring. The platform integrates a security case management system to organize investigations by tracking detections and grouping related security events. It provides capabilities for full packet capture, network metadata extraction, and the collection and indexing of security logs from dive

Hayabusa is a Windows event log analyzer, threat hunting tool, and forensic timeline generator. It functions as a detection engine that applies threat patterns to logs to identify suspicious behavior and security threats. The project distinguishes itself through the ability to synchronize detection rules from remote repositories and tune risk levels to prioritize critical alerts. It also provides specialized forensic capabilities, such as extracting event log data into chronological records for incident response investigations. The tool's broader capabilities include security log enrichment

Termshark is a terminal-based network packet analyzer and protocol flow inspector. It serves as a keyboard-driven interface for the tshark command-line utility, providing a terminal user interface to monitor data flow and analyze network traffic. The tool functions as a terminal interface for Wireshark, utilizing its filtering and inspection logic to analyze recorded capture files or live network interfaces. It specifically enables the reassembly and inspection of TCP and UDP flows to isolate traffic patterns and analyze network conversations by protocol. The system includes capabilities for