sec-design.md

Okay, let's create a design document for the Grav CMS project, focusing on aspects relevant to threat modeling.

BUSINESS POSTURE

Grav is a flat-file content management system (CMS). It's designed to be fast, simple, and flexible, appealing to users who want a lightweight alternative to database-driven CMSs like WordPress or Drupal. The business priorities likely revolve around:

• Ease of Use: Attracting users with a simple installation and management process.
• Performance: Providing a fast website experience, leveraging its flat-file architecture.
• Extensibility: Allowing users to customize and extend functionality through plugins and themes.
• Community: Fostering a strong community for support, development, and contribution.
• Reputation: Maintaining a reputation for being secure, reliable, and well-maintained.

Based on these priorities, the most important business risks are:

• Security Vulnerabilities: Exploitable vulnerabilities in the core CMS, plugins, or themes could lead to website defacement, data breaches, or complete site takeover. This is a critical risk given the public-facing nature of websites.
• Performance Degradation: Poorly written plugins, themes, or excessive content could negatively impact website performance, driving users away.
• Lack of Adoption: If Grav fails to attract and retain users, its long-term viability is threatened.
• Reputational Damage: Security incidents or negative user experiences could damage Grav's reputation, hindering adoption and community growth.
• Supply Chain Attacks: Compromise of third-party libraries or build processes could introduce vulnerabilities.

SECURITY POSTURE

Grav, being a self-hosted CMS, has a security posture that heavily relies on the user's implementation and the inherent security of the platform itself.

Existing Security Controls (based on the GitHub repository and general knowledge of flat-file CMSs):

• security control: Input Validation: Grav likely employs input validation to sanitize user-provided data before processing or storing it, mitigating risks like Cross-Site Scripting (XSS) and code injection. Implemented in core code and recommended for plugin/theme developers.
• security control: Configuration Hardening: Grav provides configuration options to enhance security, such as disabling unnecessary features or restricting access to sensitive files. Described in documentation and configuration files.
• security control: Regular Updates: The Grav team releases updates to address security vulnerabilities and improve functionality. This relies on users actively updating their installations. Described in release notes and update mechanisms.
• security control: Plugin/Theme Vetting (Limited): While there's a plugin/theme ecosystem, the level of vetting before inclusion may vary. Users should exercise caution when installing third-party extensions. Described in plugin/theme repository guidelines.
• security control: File Permissions: Proper file permissions on the server are crucial for preventing unauthorized access. This is primarily the responsibility of the user during installation and maintenance. Described in installation documentation.
• security control: .htaccess (Apache): Grav utilizes .htaccess files (on Apache servers) to configure security settings like directory listing prevention and access control. Described in default .htaccess files.
• security control: YAML Configuration: Uses YAML files for configuration, which are less prone to injection vulnerabilities compared to executable configuration files. Implemented in core code.

Accepted Risks:

• accepted risk: User Responsibility: A significant portion of the security responsibility rests with the user, including server configuration, plugin/theme selection, and regular updates.
• accepted risk: Third-Party Plugin/Theme Risk: While the core Grav system might be secure, vulnerabilities in third-party plugins or themes can compromise the entire site.
• accepted risk: Limited Built-in Protections: Compared to some enterprise-grade CMSs, Grav may have fewer built-in security features like Web Application Firewalls (WAFs) or Intrusion Detection Systems (IDSs).

Recommended Security Controls:

• security control: Security Audits: Regular security audits (both manual code review and automated scanning) of the core Grav code and popular plugins/themes.
• security control: Content Security Policy (CSP): Implementing CSP headers to mitigate XSS and other code injection attacks.
• security control: Two-Factor Authentication (2FA): Offering 2FA for administrative accounts to enhance login security.
• security control: Security Headers: Enforcing the use of security-related HTTP headers (e.g., HSTS, X-Frame-Options, X-Content-Type-Options).
• security control: Automated Security Scanning: Integrating automated security scanning tools into the development and release process.

Security Requirements:

• Authentication:
  • Secure password storage using strong hashing algorithms (e.g., bcrypt, Argon2).
  • Protection against brute-force attacks (e.g., rate limiting, account lockout).
  • Optional support for multi-factor authentication.
• Authorization:
  • Role-Based Access Control (RBAC) to manage user permissions.
  • Clear separation of privileges between different user roles (e.g., administrator, editor, contributor).
  • Secure handling of user sessions.
• Input Validation:
  • Strict validation of all user-provided input, including form data, URL parameters, and file uploads.
  • Whitelist-based validation where possible, rather than blacklist-based.
  • Output encoding to prevent XSS vulnerabilities.
• Cryptography:
  • Use of strong, industry-standard cryptographic algorithms for sensitive data (e.g., passwords, API keys).
  • Secure generation and management of cryptographic keys.
  • Avoidance of deprecated or weak cryptographic algorithms.

DESIGN

C4 CONTEXT

graph LR
    subgraph "Internet"
    A[User]
    end
    B[Grav CMS]
    C[Web Server]
    D[File System]
    E[Admin User]
    A -- "Visits website" --> B
    E -- "Manages content" --> B
    B -- "Serves content" --> C
    C -- "Reads/Writes files" --> D

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Context Diagram Element List:

• Element:

  • Name: User
  • Type: Person
  • Description: A person who visits the website hosted by Grav CMS.
  • Responsibilities: Browses website content, interacts with forms (if any).
  • Security controls: Browser security settings, safe browsing practices.

• Element:

  • Name: Admin User
  • Type: Person
  • Description: A person who manages the content and configuration of the Grav CMS.
  • Responsibilities: Creates, edits, and deletes content; manages users; installs plugins and themes; configures the CMS.
  • Security controls: Strong passwords, secure network connection, potentially 2FA.

• Element:

  • Name: Grav CMS
  • Type: Software System
  • Description: The flat-file content management system.
  • Responsibilities: Processes user requests, retrieves content from the file system, renders web pages, manages users and plugins.
  • Security controls: Input validation, output encoding, secure configuration, regular updates.

• Element:

  • Name: Web Server
  • Type: Software System
  • Description: The web server software (e.g., Apache, Nginx) that hosts the Grav CMS.
  • Responsibilities: Receives HTTP requests, serves static files, executes PHP scripts.
  • Security controls: Secure configuration, regular updates, file permissions, potentially a WAF.

• Element:

  • Name: File System
  • Type: System
  • Description: The file system of the server where Grav CMS files (content, configuration, plugins, themes) are stored.
  • Responsibilities: Stores and retrieves files.
  • Security controls: File permissions, operating system security, potentially disk encryption.

C4 CONTAINER

graph LR
    subgraph "Grav CMS"
    A[Web Server Interface]
    B[Grav Core]
    C[Plugin System]
    D[Theme System]
    E[Admin Panel]
    F[Cache]
    A -- "HTTP Requests" --> B
    B -- "Loads plugins" --> C
    B -- "Loads themes" --> D
    B -- "Manages content" --> E
    B -- "Reads/Writes" --> F
    end

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Container Diagram Element List:

• Element:

  • Name: Web Server Interface
  • Type: Component
  • Description: The interface between the web server and Grav (e.g., PHP-FPM, mod_php).
  • Responsibilities: Handles incoming HTTP requests and passes them to Grav Core.
  • Security controls: Secure configuration of the web server and PHP.

• Element:

  • Name: Grav Core
  • Type: Component
  • Description: The core functionality of the Grav CMS.
  • Responsibilities: Routing, content processing, template rendering, user management, plugin/theme loading.
  • Security controls: Input validation, output encoding, secure coding practices.

• Element:

  • Name: Plugin System
  • Type: Component
  • Description: The system for managing and loading plugins.
  • Responsibilities: Loads and executes plugins, provides APIs for plugins to interact with Grav Core.
  • Security controls: Plugin vetting (limited), sandboxing (ideally).

• Element:

  • Name: Theme System
  • Type: Component
  • Description: The system for managing and loading themes.
  • Responsibilities: Loads and applies themes, provides templating engine.
  • Security controls: Theme vetting (limited), secure template design.

• Element:

  • Name: Admin Panel
  • Type: Component
  • Description: The web-based interface for managing Grav.
  • Responsibilities: Provides UI for content management, user management, configuration, etc.
  • Security controls: Authentication, authorization, input validation, session management.

• Element:

  • Name: Cache
  • Type: Component
  • Description: Caching system to improve performance.
  • Responsibilities: Stores and retrieves cached data.
  • Security controls: Secure cache configuration, cache invalidation mechanisms.

DEPLOYMENT

Possible Deployment Solutions:

1. Traditional Web Hosting: Deploying Grav on a shared or dedicated web hosting account with a provider like Bluehost, SiteGround, etc.
2. Virtual Private Server (VPS): Deploying Grav on a VPS like DigitalOcean, Linode, or AWS Lightsail.
3. Cloud Platform (PaaS): Deploying Grav on a Platform-as-a-Service provider like Heroku or Google App Engine.
4. Containerized Deployment: Deploying Grav using Docker and a container orchestration platform like Kubernetes.

Chosen Solution (for detailed description): VPS (e.g., DigitalOcean Droplet)

graph LR
    subgraph "DigitalOcean"
    A[Droplet (VPS)]
    B[Ubuntu Server]
    C[Nginx]
    D[PHP-FPM]
    E[Grav Files]
    A -- "Runs" --> B
    B -- "Runs" --> C
    B -- "Runs" --> D
    D -- "Accesses" --> E
    end

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Deployment Diagram Element List:

• Element:

  • Name: Droplet (VPS)
  • Type: Infrastructure
  • Description: A virtual private server instance on DigitalOcean.
  • Responsibilities: Provides the computing resources for running the Grav CMS.
  • Security controls: Firewall, SSH key authentication, regular system updates.

• Element:

  • Name: Ubuntu Server
  • Type: Operating System
  • Description: The operating system running on the VPS.
  • Responsibilities: Manages system resources, runs software.
  • Security controls: Regular security updates, user account management, firewall configuration.

• Element:

  • Name: Nginx
  • Type: Web Server
  • Description: The web server software.
  • Responsibilities: Serves static files, proxies requests to PHP-FPM.
  • Security controls: Secure configuration, regular updates, potentially a WAF.

• Element:

  • Name: PHP-FPM
  • Type: Process Manager
  • Description: The FastCGI Process Manager for PHP.
  • Responsibilities: Executes PHP scripts.
  • Security controls: Secure configuration, regular updates, resource limits.

• Element:

  • Name: Grav Files
  • Type: Files
  • Description: The Grav CMS files (core, plugins, themes, content).
  • Responsibilities: Stores the website data.
  • Security controls: File permissions, regular backups.

BUILD

Grav's build process is relatively simple, as it's primarily a collection of PHP files and doesn't require compilation in the traditional sense. However, there are still build-related aspects to consider, particularly for releases and development.

graph LR
    A[Developer Workstation]
    B[GitHub Repository]
    C[GitHub Actions]
    D[Release Artifacts]
    E[Composer]
    A -- "Commits code" --> B
    B -- "Triggers build" --> C
    C -- "Runs tests" --> C
    C -- "Runs linters" --> C
    C -- "Manages dependencies" --> E
    C -- "Creates release" --> D

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Build Process Description:

1. Development: Developers work on the Grav core, plugins, and themes locally.
2. Version Control: Code is managed using Git and hosted on GitHub.
3. Dependency Management: Composer is used to manage PHP dependencies.
4. Automated Builds (GitHub Actions): GitHub Actions is used to automate tasks like:
   • Running unit tests.
   • Running code linters (e.g., PHP_CodeSniffer).
   • Managing dependencies with Composer.
   • Creating release artifacts (zip files).
5. Release: When a new version is tagged, GitHub Actions creates a release artifact (a zip file containing the Grav files) and publishes it on GitHub.

Security Controls in Build Process:

• security control: Code Review: Pull requests are used to review code changes before merging them into the main branch.
• security control: Automated Testing: Unit tests help ensure code quality and prevent regressions.
• security control: Code Linting: Linters enforce coding standards and help identify potential security issues.
• security control: Dependency Management: Composer helps manage dependencies and ensures that known vulnerable versions are not used (with proper configuration and updates).
• security control: GitHub Actions Security: Using a secure CI/CD environment like GitHub Actions, with appropriate permissions and secrets management.

RISK ASSESSMENT

Critical Business Processes:

• Website Availability: Ensuring the website is accessible to users.
• Content Management: Allowing authorized users to create, edit, and publish content.
• User Authentication: Securely authenticating users and managing their access.
• Plugin/Theme Management: Allowing users to extend functionality through plugins and themes.

Data to Protect:

• Website Content (Low to Medium Sensitivity): The actual content of the website, which may include text, images, and other media. The sensitivity depends on the nature of the website.
• User Data (Medium to High Sensitivity): Usernames, hashed passwords, email addresses, and potentially other personal information.
• Configuration Data (Medium Sensitivity): Configuration files containing settings, API keys, and potentially other sensitive information.
• System Files (High Sensitivity): Core Grav files, plugin files, and theme files. Compromise of these files could lead to complete site takeover.

QUESTIONS & ASSUMPTIONS

Questions:

• What is the specific threat model that Grav uses (if any)?
• What are the plans for implementing more robust security features like 2FA and CSP?
• What is the process for reporting and handling security vulnerabilities?
• How are plugins and themes vetted for security before being listed in the official repository?
• What level of support is provided for security-related issues?

Assumptions:

• BUSINESS POSTURE: Assumes that Grav's primary target audience is individuals and small businesses who prioritize ease of use and performance over enterprise-grade security features.
• SECURITY POSTURE: Assumes that users are responsible for securing their own server environment and keeping Grav and its components updated.
• DESIGN: Assumes a standard LAMP/LEMP stack deployment, although other configurations are possible. Assumes that GitHub Actions is the primary CI/CD pipeline.