5 Best Open Source Application Security Tools in 2025
Empowering developers with top-tier open source security tools for robust application protection
Updated November 26, 2024.
As cybersecurity becomes increasingly important in software development, the “shift left” security approach is widely recognized as a best practice for ensuring superior application security. Numerous traditional security firms are introducing shift-left products and capabilities, and the concept is gaining traction.
However, some open source application security tools are more developer-friendly than others. That’s why we’ve compiled a list of five security tools that we believe developers should be aware of, providing a brief overview of the top open-source software and explaining why we consider them to be developer-friendly.
The list aims to cover various families of code analysis tools that should be part of some minimal requirements for security:
- Static application security testing (SAST)
- Dynamic application security testing (DAST)
- Hard-coded Secrets detection
- Infrastructure as Code analysis (IaC)
» Confused? Discover the differences between SAST and DAST
What Is Open Source Software?
Open source software is free, so there is no need for budget approval, allowing you to try out a tool without having to commit to it.
Instead of lengthy selection processes, you can simply try it and see how you like it. In addition, and it is particularly critical for security tools, they let you read the entire source code so that you don't have any surprises regarding what actions the tool is performing when running it in your environment.
Our Top 5 Picks for the Best Open Source Application Security Tools
1. Best SAST tool for Python: Pycharm Python Security Scanner
2. Most configurable SAST tool: Semgrep
3. Best for finding secret leaks in code repositories: gitleaks
4. Best web vulnerability scanner: Zed Attack Proxy (ZAP)
5. Best IaC security scanner: KICS
1
Pycharm Python Security Scanner
Security scanner for python wrapped as a plugin
Learn MoreRule coverage and accuracy
Wide coverage of Python security issues.
Ease of integration and user experience
Integrates easily with GitHub Actions
Scalability and performance
Analyzing and securing Python codebases within the PyCharm IDE
Community support and documentation
Assists users in effectively using and configuring security features within the PyCharm IDE
Brief Overview
Pycharm Python Security Scanner is a security scanner for Python code wrapped as a Pycharm plugin, checking for vulnerabilities while also suggesting fixes. Alongside acting as a comprehensive security scanner, it also offers some additional extensions that can run dependency check analysis as well.
What makes it unique is that beyond being a plugin, it also available as a CI/CD workflow for GitHub Actions in the Github Marketplace.
Features
- Over 20 builtin code checks giving your contextual security warnings in your code
- Misconfiguration warnings for Django and Flask web frameworks
- Cross-Site-Scripting detection for both Jinja2 and Mako templating engines
- SQL Injection detection in all Python string formats
- Automatic reporting of known vulnerabilities and CVEs in your installed Python Packages within PyCharm
- Detection of security flaws and misconfiguration in 3rd party libraries like Jinja2, Paramiko and Mako
- Can be used to scan large code bases with inspection profiles
- Configurable alert levels and warning suppression by file, line, or project
- Scan code in your CI/CD using Docker
Pros and cons
Contextual security warnings
Web framework misconfiguration warnings
Cross-Site-Scripting (XSS) detection
SQL Injection detection
Automatic reporting of known vulnerabilities
Limited language support
2
Semgrep
Highly configurable SAST tool
Learn MoreRule coverage and accuracy
Broad coverage with customizable rules to tailor findings
Ease of integration and user experience
Semgrep integrates into the SCM or IDE
Scalability and performance
Ability to quickly analyze code in large projects and its performance in delivering results efficiently
Community support and documentation
Wide support from the community and Semgrep company
Brief Overview
Semgrep is a highly-configurable SAST tool for identifying patterns in the syntax tree. It can either run locally using Docker or be integrated into the CI/CD pipeline with Github Actions.
Results are delivered as JSON files, allowing you to pipe the results into other tools, like jq in order to manipulate them.
Features
- Runs anywhere, from CLI to CI/CD. Findings can be surfaced in developer workflows, their cloud platform, or ingested into your existing tools via API
- Built with the capabilities needed to enforce any type of AppSec program and designed to let teams tailor these capabilities to their needs
- Rules are visible to users and their syntax is similar to the source code
- 10 second median CI scan time
- AI recommendations for addressing findings
- Secure existing SDLC processes without slowing developers down
Pros and cons
Fast scan times and high accuracy for SAST
Highly configurable rule set
Support for multiple languages
Easy integration into CI/CD pipelines and IDE
Active community and regular updates
Potential learning curve for new users
3
gitleaks
Protect and discover secrets
Learn MoreRule coverage and accuracy
Hundreds of patterns that look for a wide variety of secrets
Ease of integration and user experience
Gitleaks easily integrates into the SCM and the IDE.
Scalability and performance
Gitleaks can scan large repos in minutes
Community support and documentation
Extensive documentation
Brief Overview
Gitleaks is a great project used for detecting very efficiently hardcoded secrets based on a configuration file containing hundreds of built-in regex expressions tailored to find API keys of popular SaaS platforms. It can run locally using Docker and or be integrated into the CI/CD pipeline with GitHub Actions.
Results are delivered in various formats and the rules can be easily extended to match your internal patterns.
Features
- Can detect and prevent hardcoded secrets like passwords, API keys, and tokens in git repos
- An easy-to-use, all-in-one solution for detecting past or present secrets in your code
- Can be installed using Homebrew, Docker, or Go
- Available in binary form for many popular platforms and OS types
- Can be implemented as a pre-commit hook directly in your repo or as a GitHub action using Gitleaks-Action
Pros and cons
Sensitive information detection
Customizable ruleset
Seamless CI/CD integration
Efficient scanning for large repositories
Active community support
Possibility of false positives or negatives
No ability to verify whether secrets are accessible in production
4
Zed Attack Proxy (ZAP)
Open-source tool for dynamic scanning
Learn MoreRule coverage and accuracy
A wide variety of rules that analyze applications in different ways
Ease of integration and User experience
Can be difficult to configure and deploy. See Jit's DAST for simple OWASP deployment.
Scalability and performance
Scans can require long durations for complex environments.
Community support and documentation
ZAP is the most popular DAST tool in the world, with dedicated maintainers
Brief Overview
OWASPs Zed Attack Proxy (ZAP) is another open-source tool, used for dynamic scanning (DAST). It can run locally using Docker and is providing a Github workflow to run in the CI/CD pipeline.
The common output for this tool is a report in HTML but you can also get it in JSON using some add-on.
Features
- ZAP full scan attacks the web application to find additional vulnerabilities
- Alerts are maintained as a GitHub issue in the corresponding repository, meaning that the script does perform actual "attacks" and can potentially run for a long period of time
- Full scan can run against a publicly available web application or against a locally available web application
- A detailed report (available in HTML and Markdown formats) is attached to the workflow run to get more information regarding the identified alerts
- Use the rules file to ignore false positives that occur during the ZAP scan
- The action will identify fixed issues or newly raised alerts in consequent scans and update the issue with the required information
Pros and cons
Relatively low false positive rate
Large set of rules to surface a broad variety of application vulnerabilities, including OWASP Top 10 vulnerabilities
Automated security testing in CI/CD
Integration with GitHub actions
The most popular DAST tool in the world
Potential complexity in setup and configuration
5
KICS
Code static analysis of infrastructure
Learn MoreRule coverage and accuracy
Covers all major cloud providers, Terraform, Pulumi, and Crossplane
Ease of integration and user experience
Fast integration into CI/CD pipeline
Scalability and performance
Scans large IaC scripts quickly
Community support and documentation
Maintained by Checkmarx
Brief Overview
KICS (Keeping Infrastructure as Code Secure) is an open-source project by Checkmarx, dedicated to fortifying the security of Infrastructure as Code (IaC). As a crucial element in contemporary DevOps, IaC enables organizations to codify and oversee infrastructure.
KICS responds to the escalating security demands in this area by delivering a robust static analysis tool crafted specifically for IaC scripts.
Features
- KICS conducts thorough security scans for IaC scripts, identifying vulnerabilities and misconfigurations
- Offers compatibility with major cloud platforms like AWS, Azure, and Google Cloud for widespread cloud infrastructure security.
- Compatible with Terraform, Pulumi, and Crossplane
- Fosters community collaboration, allowing customization through an extensible architecture
- Seamlessly integrates into CI/CD pipelines for automated security checks during development
- Utilizes a robust query language for defining security and compliance checks, tailoring scans to specific requirements
Pros and cons
Comprehensive IaC security
Extensive rule library
Easy integration
Scalability
Active community support
Learning curve for new users
A closer look at the criteria for open source application security tools
To us, a dev-friendly open source application security tool makes developers' (and dev leaders') lives easier by either making tasks simpler or speeding up processes.
1. They Run Locally First
Running code locally from your terminal allows software developers to launch and test code with one simple command. The ability to run a tool locally ensures that you can get immediate feedback and easily tweak the configuration. When launched from a container, you don't even have to bother with possible environmental issues related to compilation.
2. They Integrate With the CI/CD Pipeline
Open source application security tools that can be integrated into the CI/CD security pipeline have a higher value. We believe that once a tool has been used locally and has its usefulness verified, we'd like to run it continuously as part of the development lifecycle—and not only on our local machines using up local resources.
Of course, once a tool and process is part of the pipeline, the benefits are also extended across the entire dev team and codebase.
3. They Form Part of the Developer Work Environment
Developers should not be wasting time switching between development tools and security tools. All the tools on this list either run in the CI/CD pipeline (e.g. Github Actions) or as a plugin into the IDE.
4. They Have Great Documentation
Readily available documentation made for dev professionals can make or break smooth usage. With great “how-to” documentation, ramp-up and troubleshoot time is much shorter.
5. They Allow You to Configure the Output Format
If you can output the results of a certain tool in multiple formats, you then allow yourself to pipe results into another tool through an API or other form of integration. If results are only readable by humans, what you can then do with those results is limited and requires human effort and wasted time.
Application and cloud security that developers love
Adopting a “Born Left” Over “Shift Left” Approach
The industry is beginning to understand that merely “shifting left” is insufficient in a world of continuous delivery. We understand that today’s shift left open sources are not alleviating the overhead placed on developers due to the noise created and the burden of learning security and navigating each open source application security tool. It’s our responsibility to address this issue.
High-speed, forward-thinking development teams are adopting a new “born left” security strategy. In this approach, security considerations—like many other product aspects—are addressed right from the first line of code. Application security is not just delivered by the development team; it is owned by them.
» Learn more: Born left vs. shift left security
High-Velocity Development and Security
At Jit, our mission is to provide developers with an end-to-end solution for owning application security, from planning, through open-source orchestration, following an MVS approach (minimum viable security).
» See our solutions to build a modern minimum viable secure product
Development teams are being tasked with end-to-end responsibility and ownership of their products, while all along, there’s the pressure to ship code to production with high velocity.
As mentioned above, while dev-friendly security tools offer great benefits, the growing responsibility assigned to developers requires a shift in today’s approach—one that requires a minimum viable mindset and automated orchestration, so that devs will be able to own application security without compromising on velocity.
