sec-design-deep-analysis.md

Deep Analysis of Cucumber-Ruby Security Considerations

1. Objective, Scope, and Methodology

Objective: To conduct a thorough security analysis of the Cucumber-Ruby testing framework, identifying potential vulnerabilities, attack vectors, and weaknesses in its design and implementation. The analysis will focus on key components, including the CLI, feature file parsing, step definition execution, dependency management, and the build/release process. The goal is to provide actionable recommendations to improve the security posture of Cucumber-Ruby and mitigate risks to users and the applications they test.

Scope: This analysis covers the Cucumber-Ruby framework itself, as available on its GitHub repository (https://github.com/cucumber/cucumber-ruby). It includes:

• Core components: CLI, feature file parser, step definition execution engine.
• Dependency management: Bundler and related mechanisms.
• Build and release process: GitHub Actions workflows.
• Integration with external systems: Indirectly, through the applications being tested. We will not analyze the security of those external systems, but we will consider how Cucumber-Ruby interacts with them.
• Security controls: Existing and recommended controls identified in the Security Design Review.

This analysis excludes:

• Specific applications being tested with Cucumber-Ruby (except as examples of interaction).
• Third-party plugins or extensions not directly maintained by the Cucumber-Ruby core team.
• The security of RubyGems.org itself (though we'll consider its role in distribution).

Methodology:

1. Code Review: Examine the Cucumber-Ruby source code on GitHub, focusing on areas identified as potential security concerns.
2. Documentation Review: Analyze the official Cucumber-Ruby documentation, including README, contributing guidelines, and any security-specific documentation.
3. Dependency Analysis: Investigate the dependencies declared in Gemfile and Gemfile.lock to identify potential supply chain risks.
4. Build Process Analysis: Examine the GitHub Actions workflows to understand the build, test, and release process and identify security-relevant configurations.
5. Threat Modeling: Identify potential attack vectors and vulnerabilities based on the architecture, components, and data flow inferred from the codebase and documentation. We will use the STRIDE model (Spoofing, Tampering, Repudiation, Information Disclosure, Denial of Service, Elevation of Privilege) to guide this process.
6. Security Design Review Analysis: Leverage the provided Security Design Review as a starting point and expand upon its findings.
7. Best Practices: Compare the observed practices against industry-standard security best practices for Ruby development and testing frameworks.

2. Security Implications of Key Components

Let's break down the security implications of each key component, referencing the C4 diagrams and build process:

• Cucumber CLI (Container):

  • Threats:
    • Injection Attacks: Malicious command-line arguments could potentially exploit vulnerabilities in argument parsing or lead to unintended code execution. (Tampering, Elevation of Privilege)
    • Denial of Service: Specially crafted arguments could cause the CLI to consume excessive resources, leading to a denial of service. (Denial of Service)
  • Mitigation:
    • Strict Input Validation: Implement robust validation and sanitization of all command-line arguments. Use a well-vetted argument parsing library (e.g., OptionParser in Ruby's standard library) and avoid using eval or similar functions on user-provided input.
    • Resource Limits: Implement limits on resource consumption (e.g., memory, CPU time) to prevent denial-of-service attacks.
    • Regular Expression Security: If regular expressions are used for argument parsing, ensure they are carefully crafted to avoid ReDoS (Regular Expression Denial of Service) vulnerabilities.

• Feature Files (.feature) (Container):

  • Threats:
    • Code Injection (Indirect): While feature files themselves are not executable, they drive the execution of step definitions. If step definitions are poorly written and execute arbitrary code based on feature file content, this could lead to code injection. (Tampering, Elevation of Privilege)
    • Information Disclosure: Feature files might inadvertently contain sensitive information (e.g., credentials, API keys) if not managed properly. (Information Disclosure)
  • Mitigation:
    • Step Definition Security: The primary mitigation lies in writing secure step definitions (see below). Feature files should be treated as untrusted input.
    • Secure Storage and Handling: Treat feature files as potentially containing sensitive data. Store them securely, avoid hardcoding credentials, and use environment variables or secure configuration management tools.
    • Review and Audit: Regularly review feature files for any accidentally included sensitive information.

• Step Definitions (.rb) (Container):

  • Threats:
    • Code Injection: The most significant risk. If step definitions execute arbitrary code based on feature file content (e.g., using eval, system, or backticks with user-provided input), attackers could inject malicious code. (Tampering, Elevation of Privilege)
    • Improper Access Control: Step definitions might interact with the application under test in ways that bypass intended security controls. (Elevation of Privilege)
    • Insecure Library Usage: Step definitions might use insecure libraries or functions, introducing vulnerabilities. (Tampering)
  • Mitigation:
    • Avoid eval, system, and backticks with untrusted input: This is crucial. Never execute code directly from feature files or user-provided data. Use parameterized step definitions and carefully sanitize any data used in system calls.
    • Principle of Least Privilege: Step definitions should only have the necessary permissions to interact with the application under test. Avoid running tests as root or with overly broad privileges.
    • Secure Coding Practices: Follow secure coding guidelines for Ruby, including input validation, output encoding, and proper error handling.
    • Dependency Management: Use Bundler to manage dependencies and regularly update gems to address known vulnerabilities.
    • Static Analysis: Use tools like RuboCop with security-focused rules to identify potential vulnerabilities in step definitions.

• Test Results (Container):

  • Threats:
    • Information Disclosure: Test results might contain sensitive information if the application under test leaks data during testing. (Information Disclosure)
    • Tampering: If test results are not stored securely, they could be tampered with to mask failures or vulnerabilities. (Tampering, Repudiation)
  • Mitigation:
    • Secure Storage: Store test results securely, especially if they might contain sensitive information.
    • Integrity Checks: Consider using checksums or digital signatures to ensure the integrity of test results.
    • Review and Audit: Regularly review test results for any unexpected output or signs of tampering.

• Ruby Application (Software System):

  • Threats: While the security of the Ruby application is outside the direct scope of this analysis, Cucumber-Ruby interacts with it. Vulnerabilities in the application can be exposed or exploited through Cucumber tests. (All STRIDE threats)
  • Mitigation: The application itself must implement robust security controls (authentication, authorization, input validation, output encoding, etc.). Cucumber-Ruby should be used to verify these controls, not to replace them.

• Build Process (GitHub Actions):

  • Threats:
    • Compromised Build Environment: Attackers could compromise the GitHub Actions environment to inject malicious code into the built gem. (Tampering, Elevation of Privilege)
    • Dependency Tampering: Attackers could compromise a dependency and inject malicious code, which would then be included in the Cucumber-Ruby gem. (Tampering, Supply Chain Attack)
    • Unauthorized Access: Unauthorized users could gain access to the GitHub repository and modify the build process or code. (Spoofing, Tampering, Elevation of Privilege)
  • Mitigation:
    • Least Privilege: Run GitHub Actions workflows with the least necessary privileges.
    • Dependency Pinning: Use Gemfile.lock to pin dependencies to specific versions, reducing the risk of unexpected changes.
    • Vulnerability Scanning: Integrate a vulnerability scanning tool (e.g., Dependabot, Snyk) into the CI pipeline to automatically detect known vulnerabilities in dependencies.
    • Code Signing: Implement code signing for released gems to ensure their integrity and authenticity. This helps users verify that the gem they are installing has not been tampered with.
    • Two-Factor Authentication (2FA): Require 2FA for all contributors to the GitHub repository.
    • Branch Protection Rules: Use branch protection rules to prevent direct pushes to the main branch and require pull requests with code reviews.
    • Regular Audits: Regularly audit the GitHub Actions workflows and security settings.
    • SBOM: Generate a Software Bill of Materials (SBOM) to track all dependencies.

• Deployment (RubyGems):

  • Threats:
    • Compromised RubyGems Account: Attackers could compromise the RubyGems account used to publish Cucumber-Ruby and upload a malicious gem. (Tampering, Elevation of Privilege)
    • Typosquatting: Attackers could publish a malicious gem with a name similar to Cucumber-Ruby, hoping users will accidentally install it. (Spoofing)
  • Mitigation:
    • Strong Passwords and 2FA: Use a strong, unique password for the RubyGems account and enable two-factor authentication.
    • API Key Restrictions: If using API keys for publishing, restrict their permissions to the minimum necessary.
    • Gem Signing: Sign released gems to ensure their integrity.
    • Monitor for Typosquatting: Regularly check for similarly named gems that might be malicious.

3. Actionable Mitigation Strategies (Tailored to Cucumber-Ruby)

Based on the above analysis, here are specific, actionable mitigation strategies:

1. Enhanced Input Validation for CLI:

   • Specific Recommendation: Review the cucumber-core and cucumber-cli gems (or their equivalents in the current codebase) for all command-line argument parsing logic. Ensure that all arguments are validated against expected types and formats. Use whitelisting where possible (e.g., only allow specific options for formatters). Document the expected input format for each option.
   • Example: If an option expects a file path, validate that it's a valid path and doesn't contain potentially dangerous characters (e.g., ../).

2. Secure Step Definition Practices (Mandatory):

   • Specific Recommendation: Create a dedicated section in the Cucumber-Ruby documentation on "Writing Secure Step Definitions." This should explicitly warn against using eval, system, or backticks with data from feature files. Provide examples of secure and insecure step definitions. Emphasize the use of parameterized step definitions.
   • Example: Show how to use step 'I visit the page named "$page_name"' with a step definition that sanitizes page_name before using it, instead of directly interpolating it into a system command.

3. Dependency Management and Vulnerability Scanning:

   • Specific Recommendation: Integrate a vulnerability scanning tool (Dependabot or Snyk) into the GitHub Actions workflow. Configure it to automatically open pull requests for dependency updates that address known vulnerabilities. Establish a process for reviewing and merging these pull requests promptly.
   • Example: Add a configuration file for Dependabot to the repository to enable automatic vulnerability scanning.

4. Code Signing for Releases:

   • Specific Recommendation: Implement code signing for all released gems using gem cert. Document the process for users to verify the signatures of downloaded gems.
   • Example: Add a step to the GitHub Actions workflow to sign the gem before publishing it to RubyGems.org. Provide instructions in the README on how to verify the signature using gem cert --verify.

5. SBOM Generation:

   • Specific Recommendation: Integrate a tool like cyclonedx-ruby or a similar SBOM generator into the build process to create a Software Bill of Materials (SBOM) for each release. Publish the SBOM alongside the released gem.
   • Example: Add a step to the GitHub Actions workflow to generate an SBOM after building the gem.

6. Security Audits and Penetration Testing:

   • Specific Recommendation: Conduct regular security audits and penetration testing of Cucumber-Ruby. This could be done by internal security experts or by engaging a third-party security firm.
   • Example: Schedule an annual penetration test focused on identifying potential injection vulnerabilities and other security weaknesses.

7. Security Vulnerability Disclosure and Response Process:

   • Specific Recommendation: Create a SECURITY.md file in the repository that clearly outlines the process for reporting security vulnerabilities. Include contact information for the security team or maintainers. Establish a timeline for responding to and addressing reported vulnerabilities.
   • Example: Provide a dedicated email address for security reports and commit to acknowledging reports within 24 hours and providing a fix or mitigation within a reasonable timeframe.

8. Review and update GitHub Actions workflows:

   • Specific Recommendation: Regularly review and update the GitHub Actions workflows to ensure they are using the latest versions of actions and that they are configured securely. Use specific SHA commit hash for the actions instead of tags.
   • Example: Instead of using actions/checkout@v3, use actions/checkout@a1234567890abcdef1234567890abcdef1234567.

9. Harden RuboCop Configuration:

   • Specific Recommendation: Enable and configure security-focused RuboCop rules, such as those related to command injection, file access, and insecure method usage.
   • Example: Add or enable rules like Security/Eval, Security/YAMLLoad, and Security/Open in the .rubocop.yml file.

These recommendations are specific to Cucumber-Ruby and address the identified threats and vulnerabilities. They are designed to be actionable and improve the overall security posture of the framework. By implementing these mitigations, the Cucumber-Ruby project can significantly reduce its risk profile and provide a more secure testing environment for its users.