Free for Open Source Application Security Tools

Author: Dave Wichers
Contributor(s): Sherif Koussa, Dirk Wetter, kingthorin, Niclas Gustafsson, Jason Hills


OWASP’s mission is to help the world improve the security of its software. One of the best ways OWASP can do that is to help Open Source developers improve the software they are producing that everyone else relies on. As such, the following lists of automated vulnerability detection tools that are free for open source projects have been gathered together here to raise awareness of their availability.

We would encourage open source projects to use the following types of tools to improve the security and quality of their code:

Disclaimer: OWASP does not endorse any of the Vendors or Scanning Tools by listing them below. They are simply listed if we believe they are free for use by open source projects. We have made every effort to provide this information as accurately as possible. If you are the vendor of a free for open source tool and think this information is incomplete or incorrect, please send an e-mail to dave.wichers (at) and we will make every effort to correct this information.

Free for Open Source Tools

Tools that are free for open source projects in each of the above categories are listed below.

SAST Tools

OWASP already maintains a page of known SAST tools: Source Code Analysis Tools, which includes a list of those that are “Open Source or Free Tools Of This Type”. Any such tools could certainly be used. One such cloud service is:

  • GitHub code scanning - A free for open source static analysis service that uses GitHub Actions and CodeQL to scan public repositories on GitHub. Supports C/C++, C#, Ruby (beta), Java, JavaScript/TypeScript, Python, and Go (see here for more information)
    • If you do not want to use GitHub Actions, you may use the CodeQL CLI; however, be sure to read the license terms in full.
    • By default, CodeQL only looks for high fidelity security related results (well known true positives), so your results may look different from LGTM.
    • To achieve the same or similar results provided by LGTM, try enabling the security-and-quality query suite within the CodeQL query pack.

In addition, we are aware of the following commercial SAST tools that are free for Open Source projects:

  • Contrast CodeSec - Scan & Serverless - Web App and API code scanners via command line or through GitHub actions. CodeSec - Scan supports Java, JavaScript and .NET, while CodeSec - Serverless supports AWS Lambda Functions (Java + Python). These tools are actually free for all projects, not just open source.
  • Coverity Scan Static Analysis - Can be lashed into Travis-CI so it’s done automatically with online resources. Supports over a dozen programming languages.
  • HCL AppScan CodeSweep - This is a SAST community edition version of HCL AppScan. Free for everyone to use. The tool currently supports Python, Ruby, JS (Vue, Node, Angular, JQuery, React, etc), PHP, Perl, Go, TypeScript & more, with new languages being added frequently.
    • CodeSweep - VS Code Plugin - Scans files upon saving them. The results show the location of a finding, type, and remediation advice. Auto-fix available with free trial or subscription.
    • CodeSweep - JetBrains Plugin - Scans files upon saving them. The results show the location of a finding, type, and remediation advice. Auto-fix available with free trial or subscription.
    • CodeSweep - GitHub Action - Scan the new code on a push/pull request using a GitHub action. Findings are highlighted in the Files Changed view and details about the issue and mitigation steps can be found in the Actions page. Unrestricted usage allowed with a free trial account.
  • Aikido - Combines open source software with custom rules & features into a single dashboard with all your security findings. Includes both SAST and Library Analysis tools. Free for small teams.
  • AppSweep - a free for everyone mobile application security testing tool for Android. It analyzes the compiled application and does not require access to the source code. The tool performs security assessment not only of the executable code but also of application resources and configuration file. Integration into CI/CD is supported.
  • Arnica - Scans all source code repositories for code risks (SAST, SCA, IaC, license violations, and low 3rd party reputation) and hardcoded secrets. The platform comes with a freemium plan for unlimited time and users count. The pipelineless security approach is the value the company charges for, so the visibility remains always free.

DAST Tools

If your project has a web application component, we recommend running automated scans against it to look for vulnerabilities. OWASP maintains a page of known DAST Tools, and the License column on this page indicates which of those tools have free capabilities. Our primary recommendation is to use one of these:

  • ZAP - A full featured free and open source DAST tool that includes both automated scanning for vulnerabilities and tools to assist expert manual web app pen testing.
  • OWASP PurpleTeam - A security regression testing SaaS and CLI, perfect for inserting into your build pipelines. You don’t need to write any tests yourself. PurpleTeam is smart enough to know how to test, you just need to provide a Job file which tells PurpleTeam what you want tested. It has two main environments local and cloud.
    • local is OWASP - set everything up yourself in your own environment.
    • cloud is a proprietary offering with everything hosted for you in the cloud. You just need to configure and run the CLI.
      PurpleTeam is pluggable, if it doesn’t have a tester that you need you can add your own. One of the testers (the web application tester) uses ZAP under the hood.
  • Arachni - Arachni is a commercially supported scanner, but its free for most use cases, including scanning open source projects.
  • CI Fuzz CLI - An open source command line tool for creating fuzz tests. The tool is tightly integrated with various build systems, enabling developers to create fuzz tests as easily as unit tests.
  • Code Intelligence App - This application security testing platform enables CI/CD-integrated fuzz testing at each pull request. It helps developers to measure and maximize code coverage and to prioritize all findings based on severity. All of this information is then aggregated in a usable dashboard. The testing platform integrates directly into popular ticketing systems and issue trackers.
  • StackHawk - StackHawk is a commercially supported DAST tool built on ZAP and optimized to run in CI/CD (almost every CI supported) to test web applications during development and in CI/CD. The StackHawk platform allows you to manage findings over time in different environments. StackHawk is free for Open Source projects and free to use on a single application.
  • VWT Digital’s sec-helpers - Collection of dynamic security related helpers. Sec-helpers is a bundle of useful tests and validators to ensure the security of a given domain.

We are not aware of any other commercial grade tools that offer their full featured DAST product free for open source projects.

IAST Tools

IAST tools are typically geared to analyze Web Applications and Web APIs, but that is vendor specific. There may be IAST products that can perform good security analysis on non-web applications as well.

We are aware of only one IAST Tool that is free after registration at this time:

  • Contrast Community Edition (CE) - Fully featured version for 1 app and up to 5 users (some Enterprise features disabled). Contrast CE supports Java and .NET only.

API Web Scanners

For tools which are API specific please refer to the OWASP community API Security Tools page.

Open Source Software (OSS) Security Tools

OSS refers to the open source libraries or components that application developers leverage to quickly develop new applications and add features to existing apps. Gartner refers to the analysis of the security of these components as software composition analysis (SCA). So OSS Analysis and SCA are the same thing.

OWASP recommends that all software projects generally try to keep the libraries they use as up-to-date as possible to reduce the likelihood of Using Components with Known Vulnerabilities (OWASP Top 10-2017 A9). There are two recommended approaches for this:

Keeping Your Libraries Updated

Using the latest version of each library is recommended because security issues are frequently fixed ‘silently’ by the component maintainer. By silently, we mean without publishing a CVE for the security fix.

  • Maven Versions plugin
    • For Maven projects, can be used to generate a report of all dependencies used and when upgrades are available for them. Either a direct report, or part of the overall project documentation using: mvn site.
  • Dependabot
    • A GitHub only service that creates pull requests to keep your dependencies up-to-date. It automatically generates a pull request for each dependency you can upgrade, which you can then ignore, or accept, as you like. It supports tons of languages.
    • Recommended for all open source projects maintained on GitHub!

Detecting Known Vulnerable Components

As an alternative, or in addition to, trying to keep all your components up-to-date, a project can specifically monitor whether any of the components they use have known vulnerable components.

Free tools of this type:

  • OWASP has its own free open source tools:
  • GitHub: Security alerts for vulnerable dependencies
    • A native GitHub feature that reports known vulnerable dependencies in your GitHub projects. Supports: Java, .NET, JavaScript, Ruby, and Python. Your GitHub projects are automatically signed up for this service.
  • Bytesafe Dependency Firewall: Free for Open Source projects
    • Detects known vulnerabilities in source code dependencies,
    • Blocks dependencies based on policies such as vulnerabilities, type of license, release dates and more
  • Debricked: free for open source projects or smaller teams.
  • retire.js: free open source tool for finding javascript libraries with known vulnerabilities. Originally a command line tool, and there are plugins for browsers and scanners.

Commercial tools of this type that are free for open source:

  • Aikido - Combines open source software with custom rules & features into a single dashboard with all your security findings. Includes both Library Analysis and SAST tools. Free for small teams.
  • Bytesafe - Bytesafe Dependency Firewall manages source code dependencies securely
  • Contrast Community Edition (CE) (mentioned earlier) also has both Known Vulnerable Component detection and Available Updates reporting for OSS. CE supports Java and .NET only.
  • Debricked - over 90% true positive rate in supported languages
    • Identifies, fixes and prevents known vulnerabilities through automation without the need to give access to your source code. Read more at
    • Allows for vulnerability management and license compliance in the same tool
    • Features automated fix pull request to automatically fix vulnerabilities (currently only for javascript)
    • Features one of the most complete vulnerability databases
    • GitHub version:
  • OX Security - Stop Attacks Across Your Software Supply Chain
    • Complete Software Supply Chain Security Solution, based on Pipeline Bill Of Materials
    • Manage your findings from a single location
      • Full visibility and end to end traceability over your software pipeline security from cloud to code.
      • Manage your findings, orchestrate DevSecOps activities, prevent risks and maintain software pipeline integrity
    • Automatically block risks introduced into the pipeline and ensure the integrity of each workload
    • Close Gaps in Security Tooling & Coverage
      • Avoid known security risks like Log4j and Codecov.
      • Prevent new attack types based on proprietary research and threat intel.
    • Improve CI/CD Security & Processes
      • Ensure the security and integrity of all cloud artifacts
      • Undertake security gap analysis and identify any blind spots.
    • Free tier for Open-Source projects
  • SOOS - Free Community Edition - Our no-hassle enrollment process for open source projects brings practical supply chain security to the masses.
    • Use with any public GitHub repository
    • C++, Node, Ruby, Python, Java, .Net, and more
    • Integrates with GitHub
    • Connect to Jira, Azure DevOps, or GitHub Issues
    • Robust license policies
    • Rich vulnerability dashboard
    • SBOM generation (SPDX/CycloneDX)
  • Snyk - Supports Node.js, Ruby, Java, Python, Scala, Golang, .NET, PHP - Latest list here:
  • Software Health Indicator by
  • SourceClear Now owned by Veracode. Supports: Java, Ruby, JavaScript, Python, Objective C, GO, PHP
  • Vulert - Vulert’s Software Composition Analysis (SCA) keeps an eye on the open source dependencies for new risks (vulnerabilities), recommends fixes, and ensures license compliance – all without requiring installation or access to the codebase. Supports Node.js, Ruby, Java, Python, Scala, Golang, .Net, PHP, C/C++ and many more.
    • At Vulert Playground, one can test an app’s security without any sign-ups. Visit Vulert Playground
    • Free for open source and small companies.
  • WhiteSource - Supports 200+ programming languages.
  • Arnica - Provides full visibility for code risks (SAST, SCA, IaC, license violations, and low 3rd party reputation) and hardcoded secrets across all source code repositories.
    • The platform comes with a freemium plan for unlimited time and users count.The pipelineless security approach is the value the company charges for, so the visibility remains always free.
    • SBOMs are generated and automatically updated across all source code repositories.
    • Supported languages: .Net, C, C++, L, Go, Java, JavaScript (including various frameworks), PHP, Python, Ruby, Rust, Scala, Swift.
    • Simplifies the risk prioritization by automatically classifying the business important of each product and correlating the potential exploitability with open source threat feeds (e.g. EPSS).

Code Quality tools

Quality has a significant correlation to security. As such, we recommend open source projects also consider using good code quality tools. A few that we are aware of are:

  • SpotBugs - Open source code quality tool for Java
    • This is the active fork for FindBugs, so if you use Findbugs, you should switch to this.
    • SpotBugs users should add the FindSecBugs plugin ( to their SpotBugs setup, as it significantly improves on the very basic security checking native to SpotBugs.
  • SonarQube
    • This is a commercially supported, very popular, free (and commercial) code quality tool. It includes most if not all the FindSecBugs security rules plus lots more for quality, including a free, internet online CI setup to run it against your open source projects. SonarQube supports numerous languages:
  • DeepScan - Supports JavaScript, TypeScript
    • DeepScan is a static code analysis tool and hosted service for inspecting JavaScript code. It checks possible run-time errors and poor code quality using data-flow analysis and provides results for the project’s code quality.
    • DeepScan is free for open source projects on GitHub.
  • MegaLinter - Multi-language Code Quality and Security checker
    • MegaLinter is an Open-Source tool that analyzes the consistency of your code, IAC, configuration, and scripts in your repository sources, to ensure all your projects repositories are clean and formatted whatever IDE/toolbox is used by their developers
    • More than 100 linters supporting 52 languages, 24 formats, 21 tooling formats, spelling and security
    • Ready to use out of the box, compliant with GitHub Actions, GitLab CI, Azure Pipelines, Jenkins, Concourse, Drone CI, or even locally with mega-linter-runner
    • Highly configurable, without registration
    • 100% Open-Source and free for all uses, powered and backed by by OX Security

Defense Tools

  • AWS Firewall Factory - An open source solution that makes it easy to deploy, update, and provision OWASP TOP 10 compliant web application firewalls (WAFs) at scale while centrally managing them with AWS Firewall Manager. This solution streamlines security management by enabling customisation of WAF configurations and adherence to AWS best practices.

Security Tools Built into DevOps/CI Environments

  • GitLab - is building security into their platform and it is quickly evolving as described here.
  • Faraday - Open Source Vulnerability Manager
    • Security has two difficult tasks: designing smart ways of getting new information, and keeping track of findings to improve remediation efforts. With Faraday, you may focus on discovering vulnerabilities while we help you with the rest. Just use it in your terminal and get your work organized on the run. Faraday was made to let you take advantage of the available tools in the community in a truly multiuser way.
    • Community Version: public open source projects on GitHub

Secrets Detection Tools

Secrets detection is often confused with SAST because both scan through static source code. Secrets detection scan the default branch before deployment but can also scan through every single commit of the git history, covering every branch, even development or test ones.

  • GitGuardian
    • A commercial tool that scans your Git repositories’ history and monitors new contributions in real-time for secrets. It examines secret exposure trends over time and monitors team performance. Free for open source repositories hosted under your GitHub Organization
    • Container Scanning ggshield is a command-line interface application to help developers detect and prevent vulnerabilities like hard coded secrets (like API keys, certificates, database connection URLs) before pushing their code to shared repositories. ggshield is integrated with GitGuardian Internal Monitoring, the automated secrets detection and remediation platform. Recently, ggshield has also integrated the capability of scanning Terraform files for infrastructure-as-code for security misconfigurations (public beta).
  • Gitleaks - Gitleaks is a fast, light-weight, portable, and open-source secret scanner for git repositories, files, and directories
  • SAP/Credential Digger - Open Source
    • A GitHub scanning tool that identifies hardcoded credentials (Passwords, API Keys, Secret Keys, Tokens, personal information, etc.), filtering the false positive data through machine learning models.
  • TruffleHog - Open Source (supported by an enterprise product: Truffle Security)
    • Find credentials in repositories (git, GitHub, GitLab), filesystem, S3 buckets, GCS buckets, syslog, CircleCI, Docket Images
    • Eliminates false positives using 700+ credential detectors that support active verification against their respective APIs
    • Available as a GitHub Action
  • Yelp/detect-secrets - Open Source
    • detect-secrets is an aptly named module for detecting secrets within a code base. Unlike other similar packages that solely focus on finding secrets, this package is designed with the enterprise client in mind: providing a backwards compatible means to prevent new secrets from entering the code base.
  • Arnica - provides full visibility for code risks (SAST, SCA, IaC, license violations, and low 3rd party reputation) and hardcoded secrets across all source code repositories.

Please let us know if you are aware of any other high quality application security tools that are free for open source (or simply add them to this page). We are particularly interested in identifying and listing commercial tools that are free for open source, as they tend to be better and easier to use than open source (free) tools. If you are aware of any missing from this list, please add them, or let us know (dave.wichers (at) and we’ll confirm they are free, and add them for you. Please encourage your favorite commercial tool vendor to make their tool free for open source projects as well!!

Finally, please forward this page to the open source projects you rely on and encourage them to use these free tools!