Top 10+ Free / Open Source SAST Tools Based on 90+k Ratings in '24

Static application security testing (SAST), also called static code analysis, is frequently delayed to later stages in a software’s development process. This is because during early stages, teams are under pressure to ship faster and lack the budget to invest in a commercial SAST tool. This leads to more refactoring work in the future as code quality issues slow down progress.

Open source SAST tools offer an alternative allowing:

• budget-conscious teams to get started with SAST from day one with free tools
• enterprise teams to add another static code analysis tool to their tech stack without impacting their budget

Sorting starting from the top:

• Sponsors with links pointing to their websites
• Products that cover multiple languages for web applications. AIMultiple counted C and C++ to be the same family of languages for this purpose.
• Programming language specific solutions for web apps.
• Solutions for native mobile apps.
• Solutions within each category is sorted by number of stars on GitHub.

To be eligible to be listed, the project needs to

• Be one of the open source projects on static analysis
• Have at least 1k stars on GitHub
• Have its last commit within the last 2 weeks

SonarQube

SonarQube offers its free community edition as an open source SAST tool. It is one of the largest SAST tool providers according to metrics like number of employees.

SonarQube is recommended if your team reviewed all SAST tools including commercial ones, chose SonarQube as its solution and decided to start with the free edition. However, if you plan to switch to another SAST tool, starting directly with the latest version of that tool would be a better choice.

OWASP Dependency-Check

OWASP Dependency-Check is not a fully featured SAST tool but leverages software composition analysis (SCA) to identify publicly disclosed vulnerabilities within a project’s dependencies.

CodeQL

CodeQL, developed by GitHub, is a code analysis engine for discovering security vulnerabilities. Security researchers share queries in its open-source community, keeping its vulnerability detection capabilities up-to-date.

Open source vs proprietary SAST tools

Though there are numerous open source source code analysis tools, they come with certain limitations:

• Programming language coverage limitations: Open source SAST tools typically cover fewer languages than proprietary software. Therefore, as your team switches between different programming languages, they may need to rely on different tools which would need to be configured, maintained and their output needs to be understood by the developers.
• Support & maintenance: Enterprise teams may prefer a solution that comes with reliable support and is maintained by an external expert team. This can help improve focus
• Updates: Code security landscape is in constant flux. Proprietary SAST tools can invest more in keeping their solutions up to date with the latest security vulnerabilities.

These disadvantages may or may not be worth the cost of a paid solution based on the specific team’s requirements. If you want to be more methodical about whether to choose an open source tool or a proprietary one:

Cost-benefit analysis of SAST tools

For such an analysis: First, evaluate both paid and open source SAST tools and create your shortlist of solutions. For top open source and paid solutions, measure

• Total cost of ownership (TCO)including licensing fees, fees for setup and integration into existing systems like the CI/CD pipeline.
• Operational costs including training for staff and maintenance.
• Efficiency gains are hard to measure but they are the reason why these tools are adopted. What is the impact of using different SAST tools on the velocity of the team? A slow tool that lacks prioritization, remediation guidance and generates a high rate of false positives can significantly slow down the development process.
• Risk Mitigation: The whole point of SAST adoption is to produce higher quality code with fewer security vulnerabilities. If a solution is failing to find critical vulnerabilities that other solutions are finding, that is a significant issue. Preventing a single security incident can save companies from significant fees and reputation damage, therefore justify the investment in a more expensive tool.
• Compliance: Heavily regulated industries, enterprises and their suppliers need to comply to a range of requirements. Capability to produce custom reports to satisfy reporting requirements can be worth significant fees.

Choosing the right static application security testing tool

The right tool can be identified in 4 steps:

• Formulate requirements such as programming languages used or planned to be used by your team
• Prepare a shortlist of solutions
• Test solutions to reduce your shortlist to 1-2 candidates
• If the solutions are proprietary, negotiate commercials and implement it in your software lifecycle.

While the right SAST tool is an important choice, static and dynamic analysis need to be considered together. An integrated application security tool supporting both approaches can provide a more comprehensive overview of security issues.

For more: How to choose your SAST tool?

Requirements for source code analysis tools

Requirements include:

• Effectiveness:
  • Supported languages such as Python, Ruby on Rails, T SQL, C or Objective C
  • Success rate in detecting security vulnerabilities and code quality issues such as code smells. Ideally this should be achieved without heavily relying on hard-to-maintain custom rules.
  • False positive rate
  • Issue prioritization so critical security issues are resolved earlier.
  • Accuracy of remediation suggestions to resolve security issues.
• Ease of use:
  • Integrations to IDEs like Visual Studio or Eclipse
  • Code review and collaboration features
  • Speed & resource consumption
  • Scalability
• Other:
  • Reporting: Especially in regulated industries, detailed reports including detailed information on security posture are important for compliance.
  • Support

For more: Key features of SAST software

How do static code analysis tools work?

Static Application Security Testing (SAST) tools parse source code, analyze potential execution flows, carry out data flow analysis and identify security vulnerabilities without executing the program. For more: How SAST tools work

Why should SAST tools be adopted?

Applications with network access are open to attacks. They could be Python applications, Ruby on Rails applications, iOS apps, Windows Mobile apps or a simple Visual Basic script.

Potential security vulnerabilities in these applications enable attackers to carry out attacks such as SQL injection, cross site scripting or take advantage of buffer overflows, security misconfigurations, hard coded secrets or race conditions. These can lead to data leaks and other security issues. Such security and privacy risks need to be minimized in any responsible corporation.

A SAST tool is a type of vulnerability scanner, that enables an efficient software development process as it helps developers to find vulnerabilities and security flaws earlier. This helps prioritize security and adopt secure coding practices without slowing down the software development process. When open source SAST tools are integrated to the IDE, they can provide real time feedback to developers, making security testing part of the development process and reducing code quality issues without disrupting the software lifecycle.

Finally, modern SAST solutions recommend remediation methods for vulnerabilities found, making it easy to improve application security.

A modern DevSecOps pipeline is incomplete without automated testing tools like SAST.

External Links

• 1. "semgrep/semgrep"
• 2. "SonarSource/sonarqube"
• 3. "github/codeql"
• 4. "jeremylong/DependencyCheck"
• 5. "pmd/pmd"
• 6. "phpstan/phpstan"
• 7. "presidentbeef/brakeman"
• 8. "PyCQA/bandit"
• 9. "danmar/cppcheck"
• 10. "nccgroup/sobelow"
• 11. "spotbugs/spotbugs"
• 12. "MobSF/Mobile-Security-Framework-MobSF"