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sec-design.md

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Okay, let's create a design document for the SortableJS library, keeping in mind its purpose and potential security considerations.

BUSINESS POSTURE

Business Priorities and Goals:

  • Provide a lightweight, dependency-free JavaScript library for creating reorderable drag-and-drop lists.
  • Offer broad browser compatibility, including touch devices.
  • Maintain a simple, easy-to-use API.
  • Ensure high performance and minimal impact on page load times.
  • Foster a strong open-source community with contributions and issue reporting.
  • Provide good documentation and examples.

Most Important Business Risks:

  • Malicious code injection through user-provided configuration or event handlers, leading to Cross-Site Scripting (XSS) vulnerabilities.
  • Denial of Service (DoS) attacks if the library is misused or exploited to cause excessive DOM manipulation or resource consumption.
  • Compatibility issues with other JavaScript libraries or frameworks, leading to unexpected behavior or breakage.
  • Data loss or corruption if the library interacts with server-side data and doesn't handle updates correctly.
  • Reputational damage due to security vulnerabilities or poor performance.

SECURITY POSTURE

Existing Security Controls:

  • security control: The library itself is primarily focused on client-side DOM manipulation and does not directly handle sensitive data or server-side interactions. This limits the attack surface. (Implicit in the library's design)
  • security control: The library's core functionality is relatively simple, reducing the likelihood of complex vulnerabilities. (Implicit in the library's design)
  • security control: The library is open-source, allowing for community review and identification of potential security issues. (GitHub repository)
  • security control: The library has unit tests. (GitHub repository)

Accepted Risks:

  • accepted risk: The library relies on the user to properly sanitize any user-provided data used in configuration options or event handlers. The library itself does not perform extensive input validation.
  • accepted risk: The library does not provide built-in protection against DoS attacks. It's the user's responsibility to ensure the library is used in a way that doesn't cause excessive resource consumption.
  • accepted risk: The library does not directly handle server-side data persistence. Any data updates resulting from list reordering must be handled by the user's application code.

Recommended Security Controls:

  • security control: Provide clear documentation and examples demonstrating how to securely use the library, especially when dealing with user-provided data.
  • security control: Consider adding optional input sanitization features or recommendations for integrating with existing sanitization libraries.
  • security control: Implement a Content Security Policy (CSP) to mitigate the impact of potential XSS vulnerabilities. This is a responsibility of the user integrating the library, but guidance should be provided.
  • security control: Add security tests to the test suite.

Security Requirements:

  • Authentication: Not directly applicable, as the library operates on the client-side and doesn't handle user authentication.
  • Authorization: Not directly applicable, as the library doesn't manage user roles or permissions.
  • Input Validation:
    • The library should provide guidance on validating user-provided data used in configuration options (e.g., group, handle, filter, etc.).
    • Consider adding optional built-in sanitization for specific options that are more prone to XSS (e.g., custom HTML content).
  • Cryptography: Not directly applicable, as the library doesn't handle encryption or cryptographic operations.

DESIGN

C4 CONTEXT

graph LR
    User["User (Web Browser)"] -- "Interacts with" --> SortableJS["SortableJS (JavaScript Library)"]
    SortableJS -- "Manipulates" --> DOM["DOM (Document Object Model)"]
    SortableJS -- "Optionally interacts with" --> WebApp["Web Application (Server-side)"]
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Element Descriptions:

  • Element:

    • Name: User (Web Browser)
    • Type: Person
    • Description: The end-user interacting with a web page that utilizes SortableJS.
    • Responsibilities:
      • Initiates drag-and-drop actions.
      • Views the reordered list.
      • May trigger server-side updates based on list changes (indirectly, through the Web Application).
    • Security Controls:
      • Browser's built-in security mechanisms (e.g., same-origin policy, XSS protection).
      • Content Security Policy (CSP) implemented by the Web Application.

  • Element:

    • Name: SortableJS (JavaScript Library)
    • Type: Software System
    • Description: The core SortableJS library, providing drag-and-drop functionality.
    • Responsibilities:
      • Handles drag-and-drop events.
      • Manipulates the DOM to reflect list reordering.
      • Provides callbacks for user interaction.
    • Security Controls:
      • Relies on user-provided input sanitization.
      • Simple core functionality.
      • Open-source code review.

  • Element:

    • Name: DOM (Document Object Model)
    • Type: Software System
    • Description: The browser's representation of the web page's structure.
    • Responsibilities:
      • Provides the structure that SortableJS manipulates.
      • Renders the visual representation of the list.
    • Security Controls:
      • Browser's built-in DOM security mechanisms.

  • Element:

    • Name: Web Application (Server-side)
    • Type: Software System
    • Description: An optional server-side application that may interact with SortableJS to persist list changes.
    • Responsibilities:
      • Receives data updates from the client-side (e.g., via AJAX).
      • Persists changes to a database or other storage.
      • Provides data to populate the initial list.
    • Security Controls:
      • Standard server-side security measures (authentication, authorization, input validation, output encoding, etc.).

C4 CONTAINER

Since SortableJS is a JavaScript library, the container diagram is essentially an extension of the context diagram.

graph LR
    User["User (Web Browser)"] -- "Interacts with" --> SortableJS["SortableJS (JavaScript Library)"]
    SortableJS -- "Manipulates" --> DOM["DOM (Document Object Model)"]
    SortableJS -- "Optionally interacts with via events" --> WebApp["Web Application Code"]
    WebApp -- "Makes requests to" --> Server["Server-side Application"]
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Element Descriptions:

  • Element:

    • Name: User (Web Browser)
    • Type: Person
    • Description: The end-user interacting with a web page.
    • Responsibilities: Initiates drag-and-drop, views reordered list.
    • Security Controls: Browser's built-in security.

  • Element:

    • Name: SortableJS (JavaScript Library)
    • Type: JavaScript Library
    • Description: Provides drag-and-drop functionality.
    • Responsibilities: Handles events, manipulates DOM.
    • Security Controls: Relies on user-provided input sanitization.

  • Element:

    • Name: DOM (Document Object Model)
    • Type: Browser API
    • Description: Browser's representation of the page structure.
    • Responsibilities: Provides structure, renders visual representation.
    • Security Controls: Browser's built-in DOM security.

  • Element:

    • Name: Web Application Code
    • Type: JavaScript Code
    • Description: The user's application code that integrates with SortableJS.
    • Responsibilities: Initializes SortableJS, handles events, communicates with the server.
    • Security Controls: Input validation, output encoding, secure communication with the server.

  • Element:

    • Name: Server-side Application
    • Type: Web Application
    • Description: Optional server-side application.
    • Responsibilities: Persists changes, provides data.
    • Security Controls: Standard server-side security measures.

DEPLOYMENT

SortableJS is a client-side library, so deployment typically involves including the library file (sortable.min.js) in a web page. There are several deployment options:

  1. Direct Download: Download the library file and host it on your web server.
  2. CDN (Content Delivery Network): Use a CDN like jsDelivr or cdnjs to include the library. This is the recommended approach for most users.
  3. Package Manager: Use a package manager like npm or yarn to install the library as a dependency. This is common for projects using build tools like Webpack or Parcel.

Chosen Deployment Solution (CDN):

graph LR
    UserBrowser["User's Web Browser"] -- "Requests sortable.min.js" --> CDN["CDN (e.g., jsDelivr)"]
    CDN -- "Serves sortable.min.js" --> UserBrowser
    UserBrowser -- "Requests other assets" --> WebServer["Web Server"]
    WebServer -- "Serves HTML, CSS, other JS" --> UserBrowser
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Element Descriptions:

  • Element:

    • Name: User's Web Browser
    • Type: Web Browser
    • Description: The user's browser accessing the web page.
    • Responsibilities: Requests and executes SortableJS, renders the page.
    • Security Controls: Browser's built-in security mechanisms.

  • Element:

    • Name: CDN (e.g., jsDelivr)
    • Type: Content Delivery Network
    • Description: A distributed network of servers that delivers SortableJS.
    • Responsibilities: Serves SortableJS quickly and reliably.
    • Security Controls: CDN's security measures (e.g., HTTPS, DDoS protection).

  • Element:

    • Name: Web Server
    • Type: Web Server
    • Description: The server hosting the web application's other assets.
    • Responsibilities: Serves HTML, CSS, and other JavaScript files.
    • Security Controls: Standard web server security measures.

BUILD

SortableJS uses a build process to create the minified distribution file (sortable.min.js). The process involves:

  1. Source Code: Developers write and modify the source code (JavaScript files in the src/ directory).
  2. Build Script: A build script (typically using tools like Rollup or Webpack) is used to:
    • Concatenate the source files.
    • Transpile the code (e.g., from ES6+ to ES5 for broader compatibility).
    • Minify the code (remove whitespace and shorten variable names) to reduce file size.
  3. Testing: Unit tests are run to ensure the code functions correctly.
  4. Distribution: The resulting minified file (sortable.min.js) is made available for download, CDN inclusion, and package manager installation.
graph LR
    Developer["Developer"] -- "Writes code" --> SourceCode["Source Code (src/)"]
    SourceCode -- "Processed by" --> BuildScript["Build Script (Rollup/Webpack)"]
    BuildScript -- "Runs" --> Tests["Unit Tests"]
    Tests -- "Pass/Fail" --> BuildScript
    BuildScript -- "Produces" --> MinifiedFile["Minified File (sortable.min.js)"]
    MinifiedFile -- "Published to" --> CDN["CDN"]
    MinifiedFile -- "Published to" --> NPM["NPM Registry"]
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Security Controls in Build Process:

  • security control: Unit Tests: The test suite helps ensure code quality and can catch potential security regressions.
  • security control: Code Review: The open-source nature of the project allows for community code review, which can identify vulnerabilities.
  • security control: Dependency Management: Package managers (npm, yarn) help manage dependencies and can be used with tools to identify known vulnerabilities in dependencies (e.g., npm audit). SortableJS has no dependencies, which eliminates this risk.
  • security control: Linting: Linters (e.g., ESLint) can be used to enforce coding standards and identify potential security issues.

RISK ASSESSMENT

Critical Business Processes:

  • Providing a functional and reliable drag-and-drop library.
  • Maintaining a positive reputation within the developer community.

Data to Protect:

  • SortableJS itself does not directly handle sensitive user data. However, it indirectly manipulates data represented in the DOM. The sensitivity of this data depends entirely on the web application using SortableJS.
  • Data Sensitivity:
    • If SortableJS is used to reorder a list of public blog post titles, the data sensitivity is low.
    • If SortableJS is used to reorder items in a shopping cart, the data sensitivity is medium (potential financial impact).
    • If SortableJS is used to reorder elements containing personal information (e.g., addresses, phone numbers), the data sensitivity is high.

QUESTIONS & ASSUMPTIONS

Questions:

  • Are there any specific security standards or compliance requirements that the web application using SortableJS must adhere to (e.g., PCI DSS, HIPAA)? This will influence the overall security posture.
  • What is the expected scale of usage? This will help determine the potential impact of DoS attacks.
  • What is the level of trust in the users who will be interacting with the SortableJS-enabled lists? This will influence the need for input validation and sanitization.

Assumptions:

  • BUSINESS POSTURE: The primary goal is to provide a functional and reliable library, with security being a secondary but important consideration.
  • SECURITY POSTURE: The user integrating SortableJS is responsible for the overall security of their web application, including input validation, server-side security, and data protection.
  • DESIGN: SortableJS will be used primarily in a web browser environment, and interaction with server-side systems is optional and handled by the user's application code. The library will be included via CDN or direct download.