Open source security software has become a key way for teams to get flexibility, transparency, and capability without licensing costs. The free tools in this roundup address problems security teams deal with, from managing large environments to catching misconfigurations and understanding how new technologies change threat exposure.
Aegis Authenticator: Free, open-source 2FA app for Android
Aegis Authenticator is an open-source 2FA app for Android that helps you manage login codes for your online accounts.
Arkime: Open-source network analysis and packet capture system
Arkime is an open-source system for large-scale network analysis and packet capture. It works with your existing security tools to store and index network traffic in standard PCAP format, making it easy to search and access.
Artemis: Open-source modular vulnerability scanner
Artemis is an open-source modular vulnerability scanner that checks different aspects of a website’s security and translates the results into easy-to-understand messages that can be shared with the organizations being scanned.
Autoswagger: Open-source tool to expose hidden API authorization flaws
Autoswagger is a free, open-source tool that scans OpenAPI-documented APIs for broken authorization vulnerabilities. These flaws are still common, even at large enterprises with mature security teams, and are especially dangerous because they can be exploited with little technical skill.
Buttercup: Open-source AI-driven system detects and patches vulnerabilities
Buttercup is a free, automated, AI-powered platform that finds and fixes vulnerabilities in open-source software. Developed by Trail of Bits, it recently earned second place in DARPA’s AI Cyber Challenge (AIxCC).
Calico: Open-source solution for Kubernetes networking, security, and observability
Calico is an open-source unified platform that brings together networking, security, and observability for Kubernetes, whether you’re running in the cloud, on-premises, or at the edge. The solution uses the lowest amount of processing resources, which is especially important in edge environments where compute resources are limited.
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.
cnspec: Open-source, cloud-native security and policy project
cnspec is an open source tool that helps when you are trying to keep a sprawling setup of clouds, containers, APIs and endpoints under control. It checks security and compliance across all of it, which makes it easier to see what needs attention.
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.
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.
EntraGoat: Vulnerable Microsoft Entra ID infrastructure to simulate identity security misconfigurations
EntraGoat is a purpose-built tool that sets up a vulnerable Microsoft Entra ID environment to mimic real-world identity security issues. It’s designed to help security professionals practice spotting and exploiting common misconfigurations.
Falco: Open-source cloud-native runtime security tool for Linux
Falco is an open-source runtime security tool for Linux systems, built for cloud-native environments. It monitors the system in real time to spot unusual activity and possible security threats.
Firezone: Open-source platform to securely manage remote access
Firezone is an open-source platform that helps organizations of any size manage secure remote access. Unlike most VPNs, it uses a least-privileged model, giving users only the access they need.
Garak: Open-source LLM vulnerability scanner
LLMs can make mistakes, leak data, or be tricked into doing things they were not meant to do. Garak is a free, open-source tool designed to test these weaknesses. It checks for problems like hallucinations, prompt injections, jailbreaks, and toxic outputs. By running different tests, it helps developers understand where a model might fail and how to make it safer.
GitPhish: Open-source GitHub device code flow security assessment tool
GitPhish is an open-source security research tool built to replicate GitHub’s device code authentication flow. It features three core operating modes: an authentication server, automated landing page deployment, and an administrative management interface.
Heisenberg: Open-source software supply chain health check tool
Heisenberg is an open-source tool that checks the health of a software supply chain. It analyzes dependencies using data from deps.dev, Software Bills of Materials (SBOMs), and external advisories to measure package health, detect risks, and generate reports for individual dependencies or entire projects.
InterceptSuite: Open-source network traffic interception tool
InterceptSuite is an open-source, cross-platform network traffic interception tool designed for TLS/SSL inspection, analysis, and manipulation at the network level.
Kanister: Open-source data protection workflow management tool
Kanister is an open-source tool that lets domain experts define how to manage application data using blueprints that are easy to share and update. It handles the complex parts of running these tasks on Kubernetes and gives a consistent way to manage different applications at scale.
Kanvas: Open-source incident response case management tool
Kanvas is an open-source incident response case management tool with a simple desktop interface, built in Python. It gives investigators a place to work with SOD (Spreadsheet of Doom) or similar files, so they can handle key tasks without jumping between different programs.
Kopia: Open-source encrypted backup tool for Windows, macOS, Linux
Kopia is an open-source backup and restore tool that lets you create encrypted snapshots of your files and store them in cloud storage, on a remote server, on network-attached storage, or on your own computer. It doesn’t create a full image of your machine. Instead, you pick the files and folders you want to back up or restore.
LudusHound: Open-source tool brings BloodHound data to life
LudusHound is an open-source tool that takes BloodHound data and uses it to set up a working Ludus Range for safe testing. It creates a copy of an Active Directory environment using previously gathered BloodHound data.
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.
Metis: Open-source, AI-driven tool for deep security code review
Metis is an open source tool that uses AI to help engineers run deep security reviews on code. Arm’s product security team built Metis to spot subtle flaws that are often buried in large or aging codebases where traditional tools struggle.
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.
Nodepass: Open-source TCP/UDP tunneling solution
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.
Nosey Parker: Open-source tool finds sensitive information in textual data and Git history
Nosey Parker is an open-source command-line tool that helps find secrets and sensitive information hidden in text files. It works like a specialized version of grep, focused on spotting things like passwords, API keys, and other confidential data.
Obot MCP Gateway: Open-source platform to securely manage the adoption of MCP servers
Obot MCP Gateway is a free, open-source gateway that enables IT organizations to securely manage and scale adoption of Model Context Protocol (MCP) servers.
OpenFGA: The open-source engine redefining access control
OpenFGA is an open-source, high-performance, and flexible authorization engine inspired by Google’s Zanzibar system for relationship-based access control. It helps developers model and enforce fine-grained access control in their applications.
Portmaster: Open-source application firewall
Portmaster is a free and open source application firewall built to monitor and control network activity on Windows and Linux. The project is developed in the EU and is designed to give users stronger privacy without asking them to manage every rule by hand.
pqcscan: Open-source post-quantum cryptography scanner
pqcscan is an open-source tool that lets users scan SSH and TLS servers to see which Post-Quantum Cryptography (PQC) algorithms they claim to support. It saves the results in JSON files. You can turn one or more of these files into an HTML report that opens in a web browser.
ProxyBridge: Open-source proxy routing for Windows applications
ProxyBridge is a lightweight, open-source tool that lets Windows users route network traffic from specific applications through SOCKS5 or HTTP proxies. It can redirect both TCP and UDP traffic and gives users the option to route, block, or allow connections on a per-application basis.
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.
Rayhunter: EFF releases open-source tool to detect cellular spying
The Electronic Frontier Foundation (EFF) has released Rayhunter, a new open-source tool designed to detect cell site simulators (CSS). These devices, also known as IMSI catchers or Stingrays, mimic cell towers to trick phones into connecting so they can collect data. Rayhunter gives researchers, journalists, and privacy advocates a way to identify suspicious cellular activity.
Reconmap: Open-source vulnerability assessment, pentesting management platform
Reconmap is an open source tool for vulnerability assessments and penetration testing. It helps security teams plan, carry out, and report on security tests from start to finish.
RIFT: New open-source tool from Microsoft helps analyze Rust malware
Microsoft’s Threat Intelligence Center has released a new tool called RIFT to help malware analysts identify malicious code hidden in Rust binaries. While Rust is becoming more popular for its speed and memory safety, those same qualities make malware written in Rust harder to analyze. RIFT is designed to cut through that complexity and make the job easier.
Secretless Broker: Open-source tool connects apps securely without passwords or keys
Secretless Broker is an open-source connection broker that eliminates the need for client applications to manage secrets when accessing target services like databases, web services, SSH endpoints, or other TCP-based systems.
sqlmap: Open-source SQL injection and database takeover tool
Finding and exploiting SQL injection vulnerabilities is one of the oldest and most common steps in web application testing. sqlmap streamlines this process. It is an open-source penetration testing tool that automates the detection and exploitation of SQL injection flaws and can take over database servers when configured to do so.
Strix: Open-source AI agents for penetration testing
Security teams know that application flaws tend to show up at the worst time. Strix presents itself as an open source way to catch them earlier by using autonomous agents that behave like human attackers. These agents run code, explore an application, uncover weaknesses, and prove those findings with working proof of concepts.
Vulnhuntr: Open-source tool to identify remotely exploitable vulnerabilities
Vulnhuntr is an open-source tool that finds remotely exploitable vulnerabilities. It uses LLMs and static code analysis to trace how data moves through an application, from user input to server output. This helps it spot complex, multi-step vulnerabilities that traditional tools often miss.
VulnRisk: Open-source vulnerability risk assessment platform
VulnRisk is an open-source platform for vulnerability risk assessment. It goes beyond basic CVSS scoring by adding context-aware analysis that reduces noise and highlights what matters. The tool is free to use and designed for local development and testing.