sec-design.md

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

BUSINESS POSTURE

Uno Platform is a cross-platform UI framework that allows developers to build native applications for multiple platforms (Windows, Web/WebAssembly, iOS, Android, macOS, and Linux) using a single codebase written in C# and XAML. The business priorities likely revolve around:

• Rapid Development: Enabling developers to build applications faster by leveraging a single codebase.
• Broad Reach: Targeting as many platforms as possible to maximize potential user base.
• Native Performance: Providing a user experience that feels native on each platform.
• Developer Adoption: Attracting and retaining developers to the platform.
• Ecosystem Growth: Fostering a vibrant community and a rich ecosystem of libraries and tools.
• Maintainability: Ensuring the platform is maintainable and evolvable over time.

Based on these priorities, some key business risks include:

• Security Vulnerabilities: Vulnerabilities in the platform could lead to compromised applications, data breaches, and reputational damage. This is a critical risk given the platform's role in building applications that may handle sensitive data.
• Platform Compatibility Issues: Inconsistencies in behavior across different platforms could lead to application instability, developer frustration, and increased support costs.
• Performance Bottlenecks: Poor performance on specific platforms could limit adoption and user satisfaction.
• Supply Chain Attacks: Compromised dependencies or build tools could introduce vulnerabilities into the platform and the applications built with it.
• Lack of Security Features: Absence of built-in security features or guidance could lead to developers building insecure applications.

SECURITY POSTURE

Based on the GitHub repository and general knowledge of cross-platform development, here's a likely security posture:

• security control: Secure Development Practices: The Uno Platform team likely follows secure coding practices, including code reviews, static analysis, and vulnerability scanning. (Evidence: General best practices for open-source projects, presence of code analysis tools in the repository.)
• security control: Dependency Management: The project uses package managers (NuGet) to manage dependencies. (Evidence: .csproj files in the repository)
• security control: Open Source: Being open source allows for community scrutiny and contributions, potentially leading to faster identification and resolution of security issues. (Evidence: Public GitHub repository)
• accepted risk: Platform-Specific Vulnerabilities: Uno Platform relies on the underlying native platforms for certain functionalities. Vulnerabilities in these platforms could impact Uno Platform applications.
• accepted risk: Third-Party Library Vulnerabilities: Applications built with Uno Platform may use third-party libraries, which could introduce their own security risks.
• security control: Input validation: Uno Platform likely performs input validation at different levels, including XAML parsing and data binding. (Evidence: General best practices for UI frameworks)
• security control: Regular Updates: The Uno Platform team likely releases regular updates to address security vulnerabilities and bug fixes. (Evidence: Release history on GitHub)

Recommended Security Controls (High Priority):

• Implement a comprehensive Software Bill of Materials (SBOM) generation process for all releases.
• Integrate Software Composition Analysis (SCA) tools into the build pipeline to identify and manage vulnerabilities in third-party dependencies.
• Perform regular penetration testing and security audits of the platform.
• Provide clear security documentation and guidance for developers building applications with Uno Platform.
• Establish a vulnerability disclosure program to encourage responsible reporting of security issues.
• Implement code signing for all released artifacts.

Security Requirements:

• Authentication:
  • Uno Platform itself does not directly handle user authentication. It relies on the application developer to implement authentication mechanisms using platform-specific APIs or third-party libraries.
  • Requirement: Provide clear guidance and examples for developers on how to securely implement authentication in Uno Platform applications, covering various scenarios (e.g., local authentication, OAuth 2.0, OpenID Connect).
• Authorization:
  • Similar to authentication, authorization is the responsibility of the application developer.
  • Requirement: Provide guidance and best practices for implementing role-based access control (RBAC) and other authorization models within Uno Platform applications.
• Input Validation:
  • Uno Platform should perform basic input validation to prevent common vulnerabilities like XAML injection.
  • Requirement: Ensure that all input from external sources (e.g., user input, network data) is properly validated and sanitized before being used.
  • Requirement: Provide mechanisms for developers to easily implement custom input validation logic.
• Cryptography:
  • Uno Platform should leverage the cryptographic capabilities of the underlying platforms.
  • Requirement: Provide clear guidance on how to use platform-specific cryptographic APIs securely.
  • Requirement: Avoid implementing custom cryptographic algorithms.
  • Requirement: Ensure secure storage of sensitive data (e.g., encryption keys, passwords) using platform-specific secure storage mechanisms.

DESIGN

C4 CONTEXT

graph LR
    subgraph Uno Platform Application
        direction LR
        UnoApp["Uno Platform App"]
    end
    User(User) --> UnoApp
    UnoApp -- "Uses" --> OS[Operating System APIs]
    UnoApp -- "Uses" --> ThirdPartyLibs[Third-Party Libraries]
    UnoApp -- "Uses" --> BackendServices[Backend Services (Optional)]

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Element Descriptions:

• Element:

  • Name: User
  • Type: Person
  • Description: A user interacting with the Uno Platform application.
  • Responsibilities: Interacting with the application's UI, providing input, and receiving output.
  • Security controls: N/A (External to the system)

• Element:

  • Name: Uno Platform App
  • Type: Software System
  • Description: An application built using the Uno Platform.
  • Responsibilities: Providing application functionality, rendering UI, handling user input, communicating with backend services (if any).
  • Security controls: Input validation, output encoding, secure communication (if applicable), adherence to platform-specific security guidelines.

• Element:

  • Name: Operating System APIs
  • Type: Software System
  • Description: The underlying operating system APIs (Windows, WebAssembly, iOS, Android, macOS, Linux).
  • Responsibilities: Providing low-level system services, including UI rendering, networking, file access, and security features.
  • Security controls: OS-level security features (e.g., sandboxing, permissions), secure storage, cryptographic APIs.

• Element:

  • Name: Third-Party Libraries
  • Type: Software System
  • Description: Third-party libraries used by the Uno Platform application.
  • Responsibilities: Providing specific functionalities not covered by the Uno Platform or the OS.
  • Security controls: Dependent on the specific library; developers should choose libraries with a good security track record and keep them updated.

• Element:

  • Name: Backend Services (Optional)
  • Type: Software System
  • Description: Backend services (e.g., APIs, databases) that the Uno Platform application interacts with.
  • Responsibilities: Providing data and business logic to the application.
  • Security controls: Authentication, authorization, input validation, secure communication (e.g., HTTPS), data encryption.

C4 CONTAINER

graph LR
    subgraph Uno Platform Application
        direction TB
        Presentation[Presentation Layer (XAML, C#)]
        BusinessLogic[Business Logic Layer (C#)]
        DataAccess[Data Access Layer (C#)]

        Presentation -- "Uses" --> BusinessLogic
        BusinessLogic -- "Uses" --> DataAccess
        DataAccess -- "Uses" --> OS[Operating System APIs]
        DataAccess -- "Uses" --> ThirdPartyLibs[Third-Party Libraries]
        DataAccess -- "Uses" --> BackendServices[Backend Services (Optional)]
    end

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Element Descriptions:

• Element:

  • Name: Presentation Layer (XAML, C#)
  • Type: Container
  • Description: Handles UI rendering and user interaction.
  • Responsibilities: Displaying data, handling user input, navigating between views.
  • Security controls: Input validation, output encoding, prevention of XAML injection.

• Element:

  • Name: Business Logic Layer (C#)
  • Type: Container
  • Description: Implements the application's core business logic.
  • Responsibilities: Processing data, enforcing business rules, coordinating with the data access layer.
  • Security controls: Input validation, authorization checks, secure handling of sensitive data.

• Element:

  • Name: Data Access Layer (C#)
  • Type: Container
  • Description: Handles data access and persistence.
  • Responsibilities: Interacting with databases, file systems, and backend services.
  • Security controls: Secure communication (e.g., HTTPS), parameterized queries (to prevent SQL injection), data encryption, secure storage of credentials.

• Element:

  • Name: Operating System APIs
  • Type: Software System
  • Description: The underlying operating system APIs.
  • Responsibilities: Providing low-level system services.
  • Security controls: OS-level security features.

• Element:

  • Name: Third-Party Libraries
  • Type: Software System
  • Description: Third-party libraries used by the application.
  • Responsibilities: Providing specific functionalities.
  • Security controls: Dependent on the specific library.

• Element:

  • Name: Backend Services (Optional)
  • Type: Software System
  • Description: Backend services that the application interacts with.
  • Responsibilities: Providing data and business logic.
  • Security controls: Authentication, authorization, input validation, secure communication, data encryption.

DEPLOYMENT

Possible deployment solutions:

1. Mobile (iOS/Android): Deployed via respective app stores (Apple App Store, Google Play Store).
2. Web (WebAssembly): Deployed as static files to a web server or CDN.
3. Windows: Deployed as an MSIX package or a traditional installer.
4. macOS: Deployed via the Apple App Store or as a standalone application package.
5. Linux: Deployed via various package managers (e.g., apt, yum, snap).

Chosen solution for detailed description: Web (WebAssembly)

graph LR
    DevMachine[Developer Machine] --> BuildServer[Build Server]
    BuildServer -- "Produces WASM files" --> WebServer[Web Server/CDN]
    WebServer -- "Serves files" --> Browser[User's Browser]

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Element Descriptions:

• Element:

  • Name: Developer Machine
  • Type: Infrastructure Node
  • Description: The developer's workstation where code is written and compiled.
  • Responsibilities: Code development, local testing.
  • Security controls: Secure coding practices, local security tools (e.g., antivirus).

• Element:

  • Name: Build Server
  • Type: Infrastructure Node
  • Description: A server that builds the WebAssembly application.
  • Responsibilities: Compiling code, running tests, packaging the application.
  • Security controls: Secure build environment, dependency scanning, static analysis.

• Element:

  • Name: Web Server/CDN
  • Type: Infrastructure Node
  • Description: A web server or CDN that hosts the WebAssembly application files.
  • Responsibilities: Serving static files to users' browsers.
  • Security controls: HTTPS, secure configuration, web application firewall (WAF).

• Element:

  • Name: User's Browser
  • Type: Infrastructure Node
  • Description: The user's web browser that runs the WebAssembly application.
  • Responsibilities: Downloading and executing the application code.
  • Security controls: Browser security features (e.g., sandboxing, same-origin policy).

BUILD

The build process for Uno Platform applications typically involves the following steps:

1. Code Development: Developers write code (C#, XAML) on their local machines.
2. Source Control: Code is committed to a source control repository (e.g., Git).
3. Build Trigger: A build is triggered (e.g., manually, on commit, on a schedule).
4. Dependency Resolution: Dependencies are resolved and downloaded (e.g., NuGet packages).
5. Compilation: The code is compiled into platform-specific assemblies.
6. Testing: Unit tests and UI tests are executed.
7. Packaging: The application is packaged into the appropriate format for each target platform (e.g., .apk, .ipa, .msix, WebAssembly files).
8. Artifact Storage: The build artifacts are stored (e.g., in a package repository, on a file server).

Security Controls in the Build Process:

• security control: Source Control Security: Access control to the source code repository.
• security control: Dependency Management: Using package managers with signed packages and vulnerability scanning.
• security control: Static Analysis: Using static analysis tools to identify potential security vulnerabilities in the code.
• security control: Software Composition Analysis (SCA): Using SCA tools to identify vulnerabilities in third-party dependencies.
• security control: Secure Build Environment: Ensuring the build server is secure and protected from unauthorized access.
• security control: Code Signing: Signing the build artifacts to ensure their integrity and authenticity.

graph LR
    Developer[Developer] --> Git[Source Control (Git)]
    Git -- "Push" --> BuildServer[Build Server (e.g., GitHub Actions, Azure DevOps)]
    BuildServer -- "NuGet Restore" --> NuGet[NuGet Server]
    BuildServer -- "Compile & Test" --> BuildServer
    BuildServer -- "SAST/SCA" --> BuildServer
    BuildServer -- "Package" --> BuildServer
    BuildServer -- "Publish Artifacts" --> ArtifactRepo[Artifact Repository]

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RISK ASSESSMENT

• Critical Business Processes:

  • Rapid application development and deployment.
  • Maintaining a secure and stable platform for building cross-platform applications.
  • Protecting the reputation of the Uno Platform and the applications built with it.

• Data Sensitivity:

  • Uno Platform itself does not handle sensitive data directly. However, applications built with Uno Platform may handle sensitive data, depending on their purpose. The sensitivity of this data will vary greatly depending on the application. Examples include:
    • Low Sensitivity: Publicly available information, non-personal data.
    • Medium Sensitivity: User preferences, application usage data.
    • High Sensitivity: Personally identifiable information (PII), financial data, health data, authentication credentials.
  • The primary data to protect within the Uno Platform project itself are:
    • Source code: Protecting against unauthorized modification or theft.
    • Build artifacts: Ensuring the integrity and authenticity of released builds.
    • Developer credentials: Protecting access to source control, build servers, and artifact repositories.

QUESTIONS & ASSUMPTIONS

• Questions:

  • What specific security certifications or compliance requirements (if any) are targeted by Uno Platform or applications built using it (e.g., HIPAA, PCI DSS)?
  • What is the current process for handling security vulnerabilities reported by external researchers?
  • Are there any specific threat models already in place for Uno Platform or its components?
  • What level of support is provided to developers for implementing security best practices in their applications?

• Assumptions:

  • BUSINESS POSTURE: Assumed that rapid development, broad reach, and developer adoption are key priorities.
  • SECURITY POSTURE: Assumed that basic secure development practices are followed. Assumed that platform-specific vulnerabilities are an accepted risk.
  • DESIGN: Assumed a standard layered architecture for Uno Platform applications. Assumed a typical build process involving source control, dependency management, compilation, testing, and packaging. Assumed WebAssembly deployment for the detailed deployment description.