List of the Top 8 Free Intrusion Detection and Prevention Systems in 2025

Empower your existing team to attain enterprise-level security with confidence. Introducing a comprehensive SIEM solution that provides endpoint visibility, around-the-clock monitoring, and automated response capabilities. By simplifying complexity, enhancing visibility, and accelerating response times, we make security management more effective. We handle the intricate details so you can focus on your everyday tasks. With Blumira's ready-to-use detections, filtered alerts, and response playbooks, IT teams can derive substantial security benefits. Rapid Deployment and Instant Outcomes: Seamlessly integrates with your existing technology stack, achieving full deployment within hours and requiring no warm-up time. Unlimited Access: Enjoy predictable pricing with no limits on data logging and complete lifecycle detection. Effortless Compliance: Comes with one year of data retention, pre-configured reports, and 24/7 automated monitoring to streamline your compliance efforts. Exceptional Support with 99.7% CSAT: Our Solution Architects are here to assist with product support, while our Incident Detection and Response Team is dedicated to new detections alongside our 24/7 SecOps Support. Don’t just manage security—enhance it with Blumira.

Conventional packet filters are slowly losing relevance as the trend shifts towards Next-Generation Firewalls, even among open-source solutions. Among these, OPNsense emerges as a prominent choice, offering features such as intrusion detection, application management, web filtering, and antivirus protection. Every network, regardless of scale, faces threats; even devices in domestic settings, like smartwatches and washing machines, are vulnerable and require strong security protocols. Firewalls are essential components of a holistic security approach, providing protection against both traditional and novel threats. To ensure a firewall's effectiveness, it is crucial to have a thorough understanding of its features, make sure it is user-friendly, and position it strategically within the network. OPNsense meets these vital criteria through various functionalities, making it a formidable solution. This book is designed to be an essential resource for those interested in grasping, installing, and configuring an OPNsense firewall efficiently. By delving into the complexities of OPNsense, users can significantly enhance their digital security posture. Additionally, the insights provided will empower individuals to navigate the evolving landscape of cybersecurity with confidence.

A centralized management dashboard offers an all-encompassing view of the organization, allowing for enhanced oversight and control. All components within the technology framework are interconnected with a central database, which improves operational efficiency for tasks such as monitoring, investigations, and incident response. This system utilizes both active and passive vulnerability scanners to identify potential issues early on, complemented by pre-configured reports that aid in compliance assessments. Users have the capability to monitor and manage account access and permission changes, reinforcing security protocols. Alerts are triggered for any unusual activities, enabling swift action when necessary. In addition, the dashboard supports remote management capabilities, which allows for quick responses to possible cyber threats. It also features monitoring tools for changes to sensitive data access, ensuring the protection of classified information. To further enhance security, advanced threat protection is implemented to defend endpoints and servers against new and evolving threats, thereby strengthening the overall security framework of the organization. This cohesive strategy not only simplifies operations but also significantly boosts the organization's responsiveness to risks, creating a more resilient infrastructure. Furthermore, the integration of these systems fosters better collaboration among teams, facilitating a proactive approach to cybersecurity challenges.

Elevate your security framework with LevelBlue USM Anywhere, an innovative open XDR platform designed to evolve alongside the complexities of your IT landscape and the growing requirements of your organization. Equipped with sophisticated analytics, extensive security orchestration, and automation features, USM Anywhere offers integrated threat intelligence that enhances and accelerates threat detection while streamlining response management. Its exceptional adaptability is showcased through a diverse range of integrations, referred to as BlueApps, which enhance its detection and orchestration functions across a multitude of third-party security and productivity tools. Moreover, these integrations enable the seamless activation of automated and orchestrated responses, thereby optimizing security management processes. Experience the capabilities of this transformative platform with a 14-day free trial, allowing you to explore how it can revolutionize your cybersecurity strategy and empower you to proactively counter potential threats in today's rapidly evolving digital landscape. Don't miss the opportunity to strengthen your defenses and ensure a more secure future for your enterprise.

The Suricata engine is highly proficient in real-time intrusion detection (IDS), inline intrusion prevention (IPS), network security monitoring (NSM), and offline packet capture (pcap) processing. It effectively scrutinizes network traffic through a well-defined and extensive set of rules and signature languages, enhanced by sophisticated Lua scripting capabilities that facilitate the detection of complex threats. Its seamless compatibility with standard input and output formats, such as YAML and JSON, allows for easy integration with a variety of tools, including popular SIEMs, Splunk, Logstash/Elasticsearch, Kibana, and other database systems. The continuous development of Suricata is fueled by a dynamic community dedicated to improving security, usability, and efficiency. Moreover, the project is overseen and supported by the Open Information Security Foundation (OISF), a non-profit organization committed to promoting the sustained growth and success of Suricata as an open-source project. This dedication not only guarantees the software's reliability but also fosters a culture of community contributions and collaborative efforts. Ultimately, the vibrant ecosystem surrounding Suricata serves as a testament to its adaptability and relevance in the ever-evolving landscape of cybersecurity.

OSSEC is an entirely open-source solution that comes at no cost, providing users the ability to tailor its features through various configuration options, such as adding custom alert rules and developing scripts for real-time incident responses. Atomic OSSEC further amplifies this functionality by aiding organizations in meeting essential compliance requirements like NIST and PCI DSS. It proficiently detects and alerts users to unauthorized changes within the file system and any potentially harmful activities that could compromise compliance. The open-source Atomic OSSEC detection and response platform enhances OSSEC with a plethora of advanced rules, real-time file integrity monitoring (FIM), frequent updates, seamless software integrations, integrated active response capabilities, an intuitive graphical user interface (GUI), compliance resources, and dedicated professional support. This combination results in a highly versatile security solution that merges extended detection and response (XDR) with compliance features into a single, comprehensive offering. The extensive flexibility and thoroughness of this system render it an essential asset for organizations seeking to strengthen their security posture while ensuring adherence to regulatory standards. With such a robust framework, organizations can confidently navigate the complexities of cybersecurity and compliance.

Safeguard your organization against credential-stuffing threats and vulnerabilities stemming from external data breaches. With countless records, encompassing email addresses, usernames, and passwords, compromised, cybercriminals exploit this information to systematically infiltrate organizations' systems and networks for a range of malicious activities. HEROIC EPIC serves as an Identity Breach Intelligence Platform™ designed to detect and thwart credential stuffing as well as account takeover attempts, ensuring robust protection for your digital assets. Additionally, by utilizing advanced analytics, it empowers organizations to proactively manage risks associated with identity breaches.

CrowdSec is a collaborative and open-source intrusion prevention system that not only analyzes behavioral patterns but also effectively responds to attacks while sharing valuable intelligence within its community. With a larger presence than cybercriminals, it empowers users to develop personalized intrusion detection systems by employing behavioral scenarios to detect potential threats. Users can take advantage of a crowdsourced and curated cyber threat intelligence platform to enhance their security measures. Additionally, you can specify the types of remediation actions you want to implement and utilize the community's IP blocklist to automate your protective strategies. CrowdSec is versatile and can be deployed on various platforms, including containers, virtual machines, bare metal servers, or even directly through our API. By working together, our cybersecurity community is actively dismantling the anonymity of cybercriminals, which is a significant advantage we hold. Contributing to this effort is easy, as you can share IP addresses that have caused you trouble to help build and maintain an effective IP blocklist for everyone’s benefit. Notably, CrowdSec's capability to process extensive logs is remarkably efficient, outperforming Fail2ban by a factor of 60, which makes it an indispensable tool in the fight against cyber threats. Through collective effort and shared intelligence, we can create a safer digital environment for all users.