Skip to content

Latest commit

 

History

History
143 lines (126 loc) · 15.9 KB

sec-design-deep-analysis.md

File metadata and controls

143 lines (126 loc) · 15.9 KB

Okay, let's perform a deep security analysis of Grav CMS based on the provided design review.

1. Objective, Scope, and Methodology

  • Objective: To conduct a thorough security analysis of Grav CMS's key components, identifying potential vulnerabilities, assessing their impact, and recommending specific mitigation strategies. The analysis will focus on the core system, plugin/theme architecture, data handling, and deployment configurations.
  • Scope:
    • Grav Core: The core codebase responsible for routing, content processing, and overall CMS functionality.
    • Plugin System: The mechanism for extending Grav's functionality.
    • Theme System: The mechanism for controlling the visual presentation of the website.
    • Admin Panel: The web interface for managing the CMS.
    • Data Storage: How Grav stores content, configuration, and user data (flat-file system).
    • Deployment: A typical VPS deployment scenario (as described in the design review).
    • Build Process: The automated build and release process using GitHub Actions.
  • Methodology:
    1. Architecture Review: Analyze the provided C4 diagrams and element descriptions to understand the system's architecture, components, and data flow.
    2. Codebase Inference: Infer security-relevant details from the codebase structure and available documentation on GitHub (https://github.com/getgrav/grav). This includes examining file organization, common coding patterns, and security-related configurations.
    3. Threat Modeling: Identify potential threats based on the identified components, data flows, and business risks. We'll use a combination of STRIDE (Spoofing, Tampering, Repudiation, Information Disclosure, Denial of Service, Elevation of Privilege) and attack trees to systematically explore vulnerabilities.
    4. Vulnerability Analysis: Assess the likelihood and impact of each identified threat.
    5. Mitigation Recommendations: Propose specific, actionable mitigation strategies tailored to Grav's architecture and deployment model.

2. Security Implications of Key Components

Let's break down the security implications of each component, drawing inferences from the codebase and documentation:

  • Grav Core (Component):

    • Threats:
      • Code Injection: Vulnerabilities in core PHP code could allow attackers to execute arbitrary code on the server (e.g., through improper handling of user input, file uploads, or dynamic code evaluation).
      • XSS (Cross-Site Scripting): Insufficient output encoding could allow attackers to inject malicious scripts into web pages, targeting other users.
      • CSRF (Cross-Site Request Forgery): Lack of CSRF protection could allow attackers to trick authenticated users into performing unintended actions.
      • Path Traversal: Vulnerabilities in file handling could allow attackers to access files outside the intended directory.
      • Logic Flaws: Errors in the core logic could lead to unexpected behavior or security vulnerabilities.
    • Codebase Inference: Grav uses Twig for templating. Twig has auto-escaping enabled by default, which helps mitigate XSS. However, developers must be careful when using the raw filter, as it disables auto-escaping. Grav's reliance on YAML for configuration is generally good, as it avoids the risks of executable configuration files. The core code likely includes input validation routines, but their effectiveness needs careful scrutiny.
    • Mitigation:
      • Rigorous Input Validation: Implement strict, whitelist-based input validation for all user-supplied data, including URL parameters, form data, and file uploads. Use a consistent validation library throughout the core.
      • Output Encoding: Ensure all output is properly encoded to prevent XSS. Leverage Twig's auto-escaping and be extremely cautious with the raw filter.
      • CSRF Protection: Implement CSRF tokens for all state-changing actions, particularly in the admin panel.
      • Secure File Handling: Use secure file handling functions and avoid using user input directly in file paths. Implement path traversal checks.
      • Regular Code Audits: Conduct regular security audits of the core codebase, including both manual code review and automated static analysis.
      • Principle of Least Privilege: Ensure that the web server process runs with the minimum necessary privileges.

  • Plugin System (Component):

    • Threats:
      • All Core Threats (Amplified): Plugins can introduce any of the vulnerabilities listed for the core, but with a higher likelihood due to potentially less rigorous development practices and limited vetting.
      • Dependency Vulnerabilities: Plugins may rely on third-party libraries that contain vulnerabilities.
      • Malicious Plugins: Attackers could create and distribute malicious plugins through the official repository or other channels.
    • Codebase Inference: Grav's plugin system allows developers to hook into various events and extend the core functionality. This provides significant power but also introduces a large attack surface. The level of sandboxing or isolation between plugins is likely limited.
    • Mitigation:
      • Plugin Security Guidelines: Provide clear and comprehensive security guidelines for plugin developers, emphasizing secure coding practices, input validation, and output encoding.
      • Plugin Vetting Process: Implement a more robust vetting process for plugins submitted to the official repository, including automated security scanning and manual code review (at least for popular plugins).
      • Dependency Management: Encourage plugin developers to use Composer and keep their dependencies up to date. Consider using tools like Dependabot to automatically identify and update vulnerable dependencies.
      • User Education: Educate users about the risks of installing third-party plugins and encourage them to only install plugins from trusted sources.
      • Runtime Plugin Monitoring (Ideal): Explore options for runtime monitoring of plugin behavior to detect suspicious activity (e.g., excessive file access, network connections). This is a more advanced mitigation.

  • Theme System (Component):

    • Threats:
      • XSS: Themes primarily control the presentation layer, making XSS the most significant threat. Malicious themes could inject scripts through templates.
      • File Inclusion: If themes are allowed to include arbitrary files, this could lead to code execution.
    • Codebase Inference: Themes use Twig templates, inheriting the same security considerations as the core. The ability of themes to execute arbitrary PHP code is likely limited, but this should be verified.
    • Mitigation:
      • Theme Security Guidelines: Provide security guidelines for theme developers, focusing on secure template design and avoiding the use of the raw filter unless absolutely necessary.
      • Theme Vetting Process: Implement a vetting process for themes similar to the plugin vetting process.
      • Restrict Theme Capabilities: Ensure that themes cannot execute arbitrary PHP code or include arbitrary files.
      • Content Security Policy (CSP): A strong CSP can significantly mitigate the impact of XSS vulnerabilities in themes.

  • Admin Panel (Component):

    • Threats:
      • Authentication Bypass: Vulnerabilities in the authentication mechanism could allow attackers to gain administrative access.
      • Brute-Force Attacks: Weak password policies and lack of rate limiting could allow attackers to guess passwords.
      • Session Hijacking: Improper session management could allow attackers to hijack authenticated sessions.
      • CSRF: Attackers could trick administrators into performing actions they didn't intend.
      • All Core Threats: The admin panel is a critical entry point, making it a target for all types of attacks.
    • Codebase Inference: The admin panel likely uses a combination of server-side PHP code and client-side JavaScript. It relies on secure session management and authentication mechanisms.
    • Mitigation:
      • Strong Password Policies: Enforce strong password policies, including minimum length, complexity requirements, and password hashing using bcrypt or Argon2.
      • Two-Factor Authentication (2FA): Implement 2FA for all administrative accounts. This is a crucial mitigation.
      • Rate Limiting: Implement rate limiting on login attempts to prevent brute-force attacks.
      • Secure Session Management: Use secure, HTTP-only cookies for session management. Generate new session IDs after successful login. Implement session timeouts.
      • CSRF Protection: Implement CSRF tokens for all state-changing actions in the admin panel.
      • Input Validation and Output Encoding: Apply the same rigorous input validation and output encoding principles as in the core.
      • Regular Security Audits: Conduct regular security audits of the admin panel code.

  • Data Storage (File System):

    • Threats:
      • Unauthorized Access: Improper file permissions could allow unauthorized users to read, modify, or delete sensitive files.
      • Data Leakage: Configuration files or other sensitive data could be exposed if the web server is misconfigured.
      • Path Traversal: Attackers could exploit vulnerabilities to access files outside the intended directory.
    • Codebase Inference: Grav stores content, configuration, and user data in YAML files within the file system. This makes file permissions and server configuration crucial.
    • Mitigation:
      • Strict File Permissions: Follow the principle of least privilege and set the most restrictive file permissions possible. The web server user should only have read access to most files and write access only to specific directories (e.g., the cache and logs directories).
      • .htaccess Configuration (Apache): Use .htaccess files to prevent direct access to sensitive directories and files (e.g., the system and user directories).
      • Web Server Configuration: Configure the web server (e.g., Nginx) to prevent directory listing and restrict access to sensitive files.
      • Regular Backups: Implement regular backups of the entire Grav installation, including the file system, to allow for recovery in case of data loss or compromise.
      • Avoid Storing Sensitive Data in Plain Text: If possible, avoid storing sensitive data like API keys directly in configuration files. Consider using environment variables or a dedicated secrets management solution.

  • Deployment (VPS):

    • Threats:
      • SSH Brute-Force Attacks: Attackers could attempt to gain SSH access to the server.
      • Vulnerable Software: Outdated operating system packages or web server software could contain vulnerabilities.
      • Misconfiguration: Incorrectly configured firewall rules or other server settings could expose the server to attack.
    • Mitigation:
      • SSH Key Authentication: Disable password-based SSH login and use SSH key authentication.
      • Firewall: Configure a firewall (e.g., UFW) to allow only necessary traffic (e.g., HTTP, HTTPS, SSH).
      • Regular System Updates: Keep the operating system and all installed software up to date with the latest security patches.
      • Fail2Ban: Install and configure Fail2Ban to automatically block IP addresses that exhibit malicious behavior (e.g., repeated failed login attempts).
      • Intrusion Detection System (IDS): Consider installing an IDS (e.g., OSSEC) to monitor for suspicious activity on the server.
      • Security Hardening Guides: Follow security hardening guides for the chosen operating system (e.g., Ubuntu) and web server (e.g., Nginx).

  • Build Process (GitHub Actions):

    • Threats:
      • Compromised Dependencies: Vulnerabilities in third-party libraries used by Grav or its build process.
      • Malicious Code Injection: Attackers could attempt to inject malicious code into the build process itself.
      • Secrets Leakage: Sensitive information (e.g., API keys, deployment credentials) could be exposed if not handled securely.
    • Mitigation:
      • Dependency Scanning: Use tools like Dependabot or Snyk to automatically scan for vulnerable dependencies and generate pull requests to update them.
      • Code Review: Require code review for all changes to the build process.
      • Secrets Management: Use GitHub Actions secrets to securely store sensitive information. Avoid hardcoding secrets in the workflow files.
      • Least Privilege: Grant the GitHub Actions workflow only the minimum necessary permissions.
      • Regular Audits: Regularly review the GitHub Actions workflow configuration for security issues.

3. Actionable Mitigation Strategies (Tailored to Grav)

Here's a summary of the most critical and actionable mitigation strategies, prioritized based on their impact and feasibility:

  1. Implement Two-Factor Authentication (2FA) for the Admin Panel: This is the single most impactful change to improve Grav's security posture.
  2. Enforce a Strong Content Security Policy (CSP): A well-crafted CSP can significantly mitigate XSS vulnerabilities, especially those introduced by themes or plugins.
  3. Implement Robust Plugin and Theme Vetting: Improve the security review process for plugins and themes, including automated scanning and manual code review.
  4. Provide Detailed Security Guidelines for Developers: Create comprehensive documentation for plugin and theme developers, emphasizing secure coding practices.
  5. Automated Dependency Scanning: Integrate tools like Dependabot or Snyk into the build process to automatically identify and update vulnerable dependencies.
  6. Regular Security Audits: Conduct regular security audits of the core Grav code and popular plugins/themes.
  7. Strict File Permissions and Web Server Configuration: Ensure that file permissions are set correctly and that the web server is configured to prevent unauthorized access to sensitive files and directories.
  8. Rate Limiting and Brute-Force Protection: Implement rate limiting on login attempts and other sensitive actions to prevent brute-force attacks.
  9. CSRF Protection: Implement CSRF tokens for all state-changing actions, particularly in the admin panel.
  10. User Education: Educate users about security best practices, including the importance of regular updates, strong passwords, and careful plugin/theme selection.

4. Addressing Questions and Assumptions

  • Threat Model: Grav does not appear to have a publicly documented, formal threat model. This analysis serves as a starting point for developing one.
  • 2FA and CSP: These are critical features that should be prioritized for development.
  • Vulnerability Reporting: Grav has a security policy on GitHub (https://github.com/getgrav/grav/security/policy) that outlines the process for reporting vulnerabilities.
  • Plugin/Theme Vetting: The current vetting process appears to be limited. A more robust process is needed.
  • Security Support: The level of security support provided by the Grav team should be clarified.

This deep analysis provides a comprehensive overview of the security considerations for Grav CMS. By implementing the recommended mitigation strategies, the Grav team and its users can significantly improve the security of their websites. The most important next steps are implementing 2FA, CSP, and a more robust plugin/theme vetting process.