Hottest cybersecurity open-source tools of the month: October 2025
This month’s roundup features exceptional open-source cybersecurity tools that are gaining attention for strengthening security across various environments.
Chekov: Open-source static code analysis tool
Checkov is an open-source tool designed to help teams secure their cloud infrastructure and code. At its core, it’s a static code analysis tool for infrastructure as code (IaC), but it also goes a step further by providing software composition analysis (SCA) for container images and open source packages.
DefectDojo: Open-source DevSecOps platform
DefectDojo is an open-source tool for DevSecOps, application security posture management (ASPM), and vulnerability management. It helps teams manage security testing, track and remove duplicate findings, handle remediation, and generate reports.
Nagios: Open-source monitoring solution
Nagios is an open-source monitoring solution, now included as part of the robust Nagios Core Services Platform (CSP). It delivers end-to-end visibility across the entire IT infrastructure, covering everything from websites and DNS to servers, routers, switches, workstations, and critical services. It helps organizations proactively detect issues, minimize downtime, and ensure the reliability of their systems.
Maltrail: Open-source malicious traffic detection system
Maltrail is an open-source network traffic detection system designed to spot malicious or suspicious activity. It works by checking traffic against publicly available blacklists, as well as static lists compiled from antivirus reports and user-defined sources. These “trails” can include domain names, URLs, IP addresses, or even HTTP User-Agent values. On top of that, Maltrail can use optional heuristic methods to identify new or unknown threats, such as emerging malware.
Nodepass: Open-source TCP/UDP tunneling solution
Nodepass architecture
When you think of network tunneling, “lightweight” and “enterprise-grade” rarely appear in the same sentence. NodePass, an open-source project, wants to change that. It’s a compact but powerful TCP/UDP tunneling solution built for DevOps teams and system administrators who need to manage complex network environments without wading through configuration files or rigid infrastructure setups.
Dependency-Track: Open-source component analysis platform
Software is a patchwork of third-party components, and keeping tabs on what’s running under the hood has become a challenge. The open-source platform Dependency-Track tackles that problem head-on. Rather than treating software composition as a one-time scan, it continuously monitors every version of every application, giving organizations a live view of risk across their entire portfolio.
Proximity: Open-source MCP security scanner
Proximity is a new open-source tool that scans Model Context Protocol (MCP) servers. It identifies the prompts, tools, and resources that a server makes available, and it can evaluate how those elements might introduce security risks. The tool also work with NOVA, a rule engine that checks for issues such as prompt injection or jailbreak attempts.
Must read:
- 35 open-source security tools to power your red team, SOC, and cloud security
- GitHub CISO on security strategy and collaborating with the open-source community
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