25 Best Open Source Security Tools for Code Testing in 2025

Ever wonder what’s hiding in your code right now?
Spoiler: attackers are already looking for it—faster than you can patch. And odds are, there are vulnerabilities in there you haven’t even met yet.

Here’s the win—you don’t have to fight blind.
Open source security tools have quietly become the go-to weapon for devs who refuse to ship code that’s an open invitation to attackers.

The market’s booming, and static application security testing (SAST) tools are leading the charge. Why? They catch problems before they blow up production.

From Semgrep’s lightning-fast local scans to SonarQube’s multi-language inspections, these tools don’t just find bugs—they name, shame, and show you how to fix them. You’ve got Bearer tracing sensitive data, PMD hunting code smells, and MobSF ruling mobile security.

And they’re not just scanners—they plug straight into your CI/CD pipelines. No more “security later” excuses.

Pick the tools that fit your stack, your workflow, and your biggest fears.
Because in 2025, knowing you’ve got a problem isn’t enough. You need to fix it—before someone else does.

25 Top Open Source Security Tools in 2025

Open-source security tools have moved far beyond their early reputation as experimental side projects. In 2025, they’re an essential part of the security stack for everyone from independent developers to global enterprises. They combine the transparency of publicly available code with the collective expertise of a global community, which means faster innovation, better peer review, and fewer blind spots than many closed-source alternatives.

The value proposition is clear: you can inspect the code for hidden vulnerabilities, customize it to your environment, and avoid expensive licensing fees — all while benefiting from continuous community-driven improvements. Whether your goal is to secure code before it ships, detect threats in real time, hunt down vulnerabilities in infrastructure, or enforce compliance policies, there’s an open-source tool that fits the need.

Here are 20 of the best open-source security tools in 2025, spanning static code analysis, network defense, web vulnerability scanning, mobile app testing, supply chain security, and more:

1. Semgrep
2. SonarQube
3. Graudit
4. Bearer
5. PMD
6. Trivy
7. Horusec
8. Betterscan
9. Scan
10. OWASP ZAP (Zed Attack Proxy)
11. SQLMap
12. Wapiti
13. Vega
14. MobSF
15. Nikto
16. Xygeni
17. Mend
18. Snyk
19. Dependency-Check
20. Wazuh
21. Security Onion
22. Open Policy Agent (OPA)
23. Falco
24. PowerShell Empire
25. Lynis

Let’s dive into each of these tools to see what they offer

1. Semgrep: Free SAST Scanner

Semgrep is a fast, language-aware static analysis tool that scans code for vulnerabilities, bugs, and style issues. It supports dozens of languages and allows custom rules tailored to your organization’s needs. Its speed and precision make it ideal for embedding security checks into CI/CD pipelines without slowing down developers.

Features:

• Customizable rules for security and quality
• Pre-built community rule sets
• Extremely fast scans suitable for developer workflows

Best for:

Teams needing a lightweight yet precise static analysis tool that integrates easily into modern development pipelines.

2. SonarQube: Static Code Analysis

SonarQube offers deep static code analysis across more than 25 languages. It detects security vulnerabilities, code smells, and maintainability issues, presenting results in rich dashboards. It integrates with CI/CD tools to enforce coding standards and prevent flaws from reaching production.

Features:

• Extensive language support with security-focused rules
• Visual dashboards for trend tracking and compliance
• Integrations with GitHub, GitLab, Bitbucket, Jenkins

Best for:

Organizations seeking an enterprise-ready solution for code quality and security with detailed reporting.

3. Graudit: Open Source Vulnerability Scanner

Graudit is a signature-based code scanning tool that searches for insecure patterns and risky function calls. Simple and command-line friendly, it’s perfect for quick scans and automation in security workflows.

Features:

• Predefined patterns targeting common security flaws
• Supports multiple file formats and languages
• Easily scriptable for batch scanning

Best for:

Security engineers needing fast vulnerability checks without complex setup.

4. Bearer: Sensitive Data Tracker

Bearer specializes in tracking sensitive data flows within code, checking for privacy and compliance risks like GDPR or HIPAA. It maps where sensitive data is handled, helping companies secure personal and financial information.

Features:

• Automated sensitive data mapping
• Built-in privacy compliance checks
• CI/CD pipeline integration for continuous monitoring

Best for:

Organizations with strict privacy regulations needing to secure data handling in code.

5. PMD: SAST and Code Quality Tools

PMD scans source code to detect performance issues, security risks, and poor coding practices such as unused variables. It supports multiple languages and allows creation of custom rules aligned with internal standards.

Features:

• Rules for performance, maintainability, and security
• IDE and build tool integration
• Support for custom rule creation

Best for:

Development teams aiming to improve code quality and security simultaneously.

6. Trivy: Open Source Container Scanner

Trivy is a versatile scanner for containers, filesystems, and Git repositories. It detects vulnerabilities, misconfigurations, and exposed secrets, with native support for Kubernetes and Infrastructure as Code (IaC).

Features:

• Scans OS packages and application dependencies
• Misconfiguration detection for Kubernetes and Terraform
• Lightweight with offline mode

Best for:

DevSecOps teams securing containerized applications and cloud infrastructure.

7. Horusec: Multi-Tool Vulnerability Scanner

Horusec is a multi-language static analysis tool that aggregates results from various scanners into a unified report. It simplifies vulnerability management across complex codebases, making it easier for teams to triage and remediate issues.

Features:

• Combines results from multiple static analysis tools
• Seamless integration with GitHub and GitLab
• Comprehensive reporting for large projects

Best for:

Enterprises managing multi-language codebases that need consolidated security insights.

8. Betterscan: Free Vulnerability Management

Betterscan is an all-in-one vulnerability scanning platform that covers code, dependencies, and infrastructure configurations. Its centralized dashboard prioritizes issues by severity to streamline remediation.

Features:

• Unified interface for multiple scanners
• Severity-based reporting for triage
• API support for tool integrations

Best for:

Organizations wanting to centralize vulnerability detection and management.

9. Scan: Open Source Multi-Engine Scanner

Scan is a CLI-driven tool that aggregates vulnerability findings from different open-source engines. It supports scanning of containers, Infrastructure as Code (IaC), and dependencies, designed for quick and flexible security checks.

Features:

• Multi-engine scanning for broad coverage
• Supports containers, IaC, and dependencies
• Easy automation in CI/CD environments

Best for:

Security teams needing rapid, flexible scanning without complex setup.

10. OWASP ZAP: Web App Vulnerability Scanner

OWASP Zed Attack Proxy (ZAP) is a popular web application security scanner offering both automated and manual testing modes. Its active and passive scanning capabilities, combined with a rich ecosystem of plugins, make it highly adaptable.

Features:

• Active and passive scanning modes
• Built-in spider for crawling web applications
• Extensible with community add-ons and scripts

Best for:

Penetration testers and developers performing comprehensive web app security testing.

11. SQLMap: Free SQL Injection Scanner

SQLMap automates the detection and exploitation of SQL injection vulnerabilities. It supports multiple database systems and can fingerprint, enumerate, and extract data from back-end databases.

Features:

• Automated detection of SQL injection flaws
• Support for MySQL, PostgreSQL, Oracle, and more
• Database fingerprinting and data extraction

Best for:

Penetration testers focusing on database security flaws.

12. Wapiti: Black-Box Vulnerability Scanner

Wapiti is a black-box web vulnerability scanner that detects common issues such as XSS, SQL injection, and file disclosure. It uses attack payloads to identify vulnerabilities without needing source code access.

Features:

• Black-box vulnerability scanning
• Detects XSS, SQLi, SSRF, and file inclusion
• Customizable attack payloads

Best for:

Security teams performing external assessments without source code access.

13. Vega: GUI Web Vulnerability Tool

Vega is a Java-based GUI web security scanner and proxy. It combines automated scanning with manual inspection tools, allowing testers to manipulate HTTP requests and analyze vulnerabilities interactively.

Features:

• Automated scanning for common web vulnerabilities
• Intercepting proxy for manual testing
• Supports SSL and authentication handling

Best for:

Testers who want both automated scanning and fine-grained manual web testing.

14. MobSF: Mobile App SAST Scanner

MobSF (Mobile Security Framework) provides static and dynamic analysis for Android, iOS, and Windows mobile apps. It decompiles apps, detects hardcoded secrets, monitors API calls, and supports automated CI/CD integration.

Features:

• Static and dynamic analysis for multiple platforms
• Hardcoded secret detection and API monitoring
• CI/CD pipeline integration with REST API

Best for:

Mobile app developers and security teams testing apps before release.

15. Nikto: Web Server Vulnerability Scanner

Nikto is a mature web server scanner focusing on outdated software, misconfigurations, and dangerous files. It’s fast, regularly updated, and supports SSL and proxy configurations.

Features:

• Checks for over 6,700 dangerous files and programs
• Detects outdated server software
• Command-line interface with automation support

Best for:

System administrators auditing web servers for known vulnerabilities.

16. Xygeni: Supply Chain Vulnerability Scanner

Xygeni secures software supply chains by scanning CI/CD pipelines for vulnerabilities and detecting tampering in build artifacts. It helps enforce security policies throughout software delivery workflows.

Features:

• Monitors build pipelines and dependencies
• Detects software tampering and suspicious activity
• Integrates with GitHub, GitLab, Jenkins

Best for:

DevSecOps teams focusing on supply chain security.

17. Mend: Open Source Dependency Scanner

Mend (formerly WhiteSource) continuously scans dependencies for vulnerabilities and enforces license compliance. It integrates with developer tools and provides remediation guidance for open-source security issues.

Features:

• Continuous open-source dependency scanning
• License compliance and governance checks
• Real-time alerts for new vulnerabilities

Best for:

Organizations managing extensive third-party codebases.

18. Snyk: Developer-Friendly Vulnerability Scanner

Snyk is a developer-friendly security platform for scanning open source dependencies, containers, and Infrastructure as Code. It automatically suggests fixes and integrates smoothly with developer workflows.

Features:

• Vulnerability scanning for dependencies, containers, and IaC
• Automated fix pull requests
• Integrations with GitHub, GitLab, Bitbucket, and CI/CD

Best for:

Development teams embedding security into daily workflows.

19. Dependency-Check: Free Composition Analysis

OWASP Dependency-Check detects known vulnerabilities in project dependencies by referencing public vulnerability databases. It integrates with common build tools to catch issues early.

Features:

• Scans Java, .NET, Python, Node.js dependencies
• Generates reports with CVSS scores
• Supports Maven, Gradle, Jenkins integration

Best for:

Teams seeking a lightweight software composition analysis tool.

20. Wazuh: Security Monitoring Tool

Wazuh is an open-source security monitoring platform offering log analysis, intrusion detection, vulnerability assessment, and compliance reporting. It’s scalable and supports real-time alerting for large infrastructures.

Features:

• Host-based intrusion detection (HIDS)
• Log data analysis and threat intelligence
• Compliance monitoring (PCI DSS, HIPAA, GDPR)

Best for:

Enterprises requiring centralized security monitoring and compliance.

21. Security Onion: Threat Hunting Platform

Security Onion is a Linux distribution designed for threat hunting, security monitoring, and log management. It bundles powerful open-source tools like Zeek, Suricata, and the Elastic Stack to provide a comprehensive security operations platform.

Features:

• Integrated network and host monitoring tools
• Pre-configured dashboards for threat analysis
• Full packet capture and intrusion detection capabilities

Best for:

Security operations centers (SOCs) and threat hunters seeking an all-in-one monitoring solution.

22. Open Policy Agent: Policy Enforcement Tool

OPA is a policy engine that allows unified, fine-grained policy enforcement across cloud-native systems. It uses a high-level declarative language called Rego to define and enforce policies for Kubernetes, microservices, APIs, and more.

Features:

• Centralized policy management with Rego language
• Integrates with Kubernetes admission controllers and CI/CD pipelines
• Decouples policy from application logic for flexibility

Best for:

Cloud-native teams standardizing security and compliance policies across environments.

23. Falco: Runtime Security Scanner

Falco is a runtime security tool that monitors system calls to detect abnormal or suspicious behavior in containers and Kubernetes environments. It’s the CNCF’s official runtime security project and integrates well with SIEMs and alerting systems.

Features:

• Real-time detection of anomalous container activity
• Predefined and customizable detection rules
• Kubernetes audit logging integration

Best for:

DevOps and security teams securing production container workloads.

24. PowerShell Empire: Post-Exploitation Tool

PowerShell Empire is a post-exploitation framework used by red teams to simulate advanced attacks. It provides stealthy command and control over compromised Windows systems, with modules for privilege escalation, lateral movement, and data exfiltration.

Features:

• Agent-based post-exploitation for Windows environments
• Encrypted communications for stealth operations
• Integration with Metasploit for extended attack capabilities

Best for:

Red teams simulating advanced persistent threat (APT) behaviors.

25. Lynis: Unix Security Auditor

Lynis is a security auditing tool for Unix-based systems that performs in-depth scans to assess system security, compliance, and hardening needs. It’s lightweight, scriptable, and provides actionable recommendations.

Features:

• Comprehensive system and configuration auditing
• Plugin support for extended checks
• Generates detailed hardening and compliance reports

Best for:

System administrators conducting regular security health checks on Unix/Linux/macOS.

These 25 open-source security tools offer powerful, flexible, and affordable options to protect your code and infrastructure in 2025. Start with what fits your needs, layer them thoughtfully, and build strong defenses. With transparency and community support, you can secure your environment without the high costs.

Your security, simplified.

Conclusion: Choosing the Right Open Source Security Tool

Here’s the truth: you don’t need deep pockets to protect your code.
We’ve just covered 25 powerful tools—most are free, and even the paid ones start around $40/month. That’s nothing compared to the cost of a single breach.

Price isn’t the only win. These tools fit right into your world—your CI/CD pipelines, IDEs, and everyday workflows.

If you’re starting out, go light with Graudit or Trivy. Learn the ropes without friction. Ready for deeper coverage? Snyk or Mend can guide you end-to-end.

Here’s the uncomfortable truth—no single tool catches everything. The smart move? Layer them. Semgrep for static analysis, OWASP ZAP for web, MobSF for mobile. Build your own security stack.

But they only work if you use them. Security can’t be someone else’s job—it has to be part of your daily routine.

Pick one tool today. Install it. Use it. Add another next month. Build your security muscle.

Your users trust you with their data. When the next vulnerability hits, you’ll be ready—and glad you didn’t gamble on security.