sec-design-deep-analysis.md

Deep Security Analysis of Korge Game Engine

1. Objective, Scope, and Methodology

Objective:

This deep security analysis aims to provide a thorough evaluation of the security posture of the Korge game engine. The objective is to identify potential security vulnerabilities and risks associated with the engine's design, architecture, and development lifecycle. This analysis will focus on key components of Korge, inferring their functionalities and data flow from the codebase description and provided documentation, to deliver actionable and tailored security recommendations for the Korge development team. The ultimate goal is to enhance the security of the Korge engine and games built upon it, fostering trust within the developer and player communities.

Scope:

This analysis encompasses the following key areas of the Korge project, as outlined in the Security Design Review:

• Core Engine Components: Rendering Engine, Input Handling, Audio Engine, UI System, Core Engine, Development Tools, and underlying Korlibs Libraries.
• Development Lifecycle: Build process, dependency management, and release procedures.
• Deployment Architecture: Consideration of web and potentially other deployment models (desktop, mobile) to understand platform-specific security implications.
• Identified Security Requirements: Input Validation and Cryptography as specified in the Security Design Review.
• Existing and Recommended Security Controls: Evaluation of current controls and recommendations for improvement.

The analysis will primarily focus on the Korge engine itself and its immediate dependencies. Security considerations for games built using Korge will be addressed in terms of guidance and engine features, but the primary focus remains on the engine's security.

Methodology:

This deep analysis will employ the following methodology:

1. Document Review: In-depth review of the provided Security Design Review document, including business and security posture, C4 diagrams, and risk assessment.
2. Codebase Inference (Based on Description): Analysis of the component descriptions and C4 diagrams to infer the architecture, functionalities, and potential data flow within Korge. While direct codebase review is not explicitly requested, the analysis will be guided by common game engine architectures and security principles applicable to such systems.
3. Threat Modeling: Identification of potential threats and vulnerabilities for each key component based on common attack vectors against game engines and software systems in general. This will be tailored to the specific functionalities inferred for each Korge component.
4. Risk Assessment: Evaluation of the potential impact and likelihood of identified threats, considering the business context and priorities of the Korge project.
5. Mitigation Strategy Development: Formulation of specific, actionable, and tailored mitigation strategies for each identified risk, focusing on practical recommendations for the Korge development team. These strategies will consider the open-source nature of the project and the reliance on community contributions.
6. Recommendation Prioritization: Prioritization of security recommendations based on risk level and feasibility of implementation.

2. Security Implications of Key Components

Based on the C4 Container diagram and descriptions, we can analyze the security implications of each key component:

2.1 Core Engine (korge-core):

• Inferred Functionality: Scene management, game loop, resource loading, general game logic management, scripting/API exposure to developers.
• Security Implications:
  • Resource Handling Vulnerabilities: Improper handling of game assets (images, audio, scripts, data files) could lead to vulnerabilities like path traversal (accessing files outside intended directories), resource exhaustion (denial of service by loading excessively large or numerous resources), and deserialization vulnerabilities if game data is processed insecurely.
  • Game Logic Exploits: Vulnerabilities in the core game logic or scripting engine (if present) could be exploited to manipulate game state, cheat, or gain unauthorized advantages.
  • API Security: If the Core Engine exposes APIs to developers for scripting or extending functionality, insecure API design or implementation could introduce vulnerabilities.
  • Memory Management Issues: Bugs in memory management within the core engine could lead to memory leaks, buffer overflows, or use-after-free vulnerabilities, potentially causing crashes or enabling arbitrary code execution.
• Specific Threats:
  • Path Traversal: Attackers could craft malicious game assets or input to access or modify sensitive files on the server or client system.
  • Resource Exhaustion (DoS): Attackers could create or modify game assets to consume excessive resources (memory, CPU), leading to denial of service for players.
  • Game Logic Manipulation (Cheating): Exploiting flaws in game logic to gain unfair advantages, impacting game fairness and player experience.
  • Arbitrary Code Execution: In severe cases, vulnerabilities like buffer overflows or deserialization flaws could be exploited to execute arbitrary code on the player's machine.

2.2 Rendering Engine (korge-render):

• Inferred Functionality: 2D graphics rendering, sprite management, visual effects, shader processing, interaction with graphics APIs (OpenGL, WebGL, etc.).
• Security Implications:
  • Shader Exploits: Vulnerabilities in shader processing or compilation could allow attackers to inject malicious shaders that cause denial of service, information disclosure, or even arbitrary code execution (depending on the underlying graphics API and driver).
  • Rendering Pipeline Vulnerabilities: Flaws in the rendering pipeline could lead to memory corruption, buffer overflows, or other vulnerabilities when processing complex scenes or visual effects.
  • Resource Exhaustion (GPU): Maliciously crafted game content could overload the GPU, leading to denial of service or crashes.
  • Information Disclosure through Rendering: In rare cases, rendering vulnerabilities might be exploited to leak sensitive information from memory or the graphics system.
• Specific Threats:
  • Shader Injection/Exploits: Attackers could inject malicious shaders to crash the game, corrupt graphics, or potentially exploit driver vulnerabilities.
  • GPU Resource Exhaustion (DoS): Overloading the GPU with complex rendering tasks to cause denial of service.
  • Memory Corruption in Rendering: Exploiting rendering pipeline flaws to corrupt memory, potentially leading to crashes or code execution.

2.3 Input Handling (korge-input):

• Inferred Functionality: Capturing and processing input from keyboard, mouse, touch, gamepad; event handling; input abstraction for game developers.
• Security Implications:
  • Input Injection Attacks: If input data is not properly validated and sanitized before being used in game logic or UI rendering, it could be exploited for injection attacks (e.g., command injection, script injection if UI uses web technologies).
  • Buffer Overflows: Improper handling of input data, especially from external sources (network input in multiplayer games, file-based input), could lead to buffer overflows if input buffers are not sized correctly or bounds checking is insufficient.
  • Denial of Service through Input Flooding: Attackers could send excessive input events to overwhelm the input handling system, leading to denial of service.
• Specific Threats:
  • Command Injection (Less likely in core engine, more relevant in game-specific logic): If input is used to construct system commands (highly unlikely in a game engine core, but possible in game-specific scripting).
  • Script Injection (If UI uses web tech): If the UI system uses web technologies and input is directly rendered without sanitization, XSS-like vulnerabilities could arise.
  • Buffer Overflow in Input Processing: Exploiting flaws in input data parsing to cause buffer overflows and potentially code execution.
  • Input Flooding (DoS): Sending a large volume of input events to overwhelm the game engine.

2.4 Audio Engine (korge-audio):

• Inferred Functionality: Audio playback, sound effects, music management, audio decoding, audio effects processing, interaction with audio APIs.
• Security Implications:
  • Buffer Overflows in Audio Decoding: Vulnerabilities in audio decoding libraries or custom decoding logic could lead to buffer overflows when processing malformed audio files.
  • Denial of Service through Malformed Audio: Crafted audio files could exploit vulnerabilities in the audio engine to cause crashes or denial of service.
  • Resource Exhaustion (Audio Processing): Playing excessively complex or numerous audio streams could overload the audio processing system, leading to denial of service.
• Specific Threats:
  • Buffer Overflow in Audio Decoding: Exploiting vulnerabilities in audio codecs to cause buffer overflows and potentially code execution.
  • Malformed Audio File DoS: Using crafted audio files to crash the game or cause denial of service.
  • Audio Resource Exhaustion (DoS): Overloading the audio engine with excessive audio playback.

2.5 UI System (korge-ui):

• Inferred Functionality: UI component library (buttons, menus, dialogs), UI layout management, event handling for UI elements, potentially rendering UI using graphics engine or web technologies.
• Security Implications:
  • Input Validation in UI Components: UI components that accept user input (text fields, etc.) must properly validate and sanitize input to prevent injection attacks.
  • Cross-Site Scripting (XSS) if Web-Based UI: If the UI system uses web technologies (e.g., rendering UI elements as HTML), vulnerabilities similar to XSS could arise if user-controlled data is not properly escaped during UI rendering.
  • UI Manipulation Vulnerabilities: Flaws in UI event handling or state management could allow attackers to manipulate the UI in unintended ways, potentially leading to game exploits or information disclosure.
• Specific Threats:
  • XSS-like Vulnerabilities (If Web UI): Injecting malicious scripts through UI input fields if the UI rendering is not secure.
  • UI Input Validation Issues: Exploiting lack of input validation in UI components to cause errors or unexpected behavior.
  • UI Manipulation Exploits: Manipulating UI elements or events to gain unfair advantages or access restricted features.

2.6 Development Tools (korge-tools):

• Inferred Functionality: Scene editor, asset management tools, debugging tools, project creation wizards, potentially code generation or scripting tools.
• Security Implications:
  • Vulnerabilities in Tools Compromising Projects: Vulnerabilities in development tools could be exploited to compromise game projects. For example, a scene editor vulnerability could allow an attacker to inject malicious code into scene files, which would then be executed when the game loads the scene.
  • Insecure Storage of Project Data: Development tools might store project data (scenes, assets, configuration files) insecurely, potentially exposing sensitive information or allowing unauthorized modification.
  • Dependency Vulnerabilities in Tools: Development tools themselves might rely on third-party libraries with vulnerabilities, which could be exploited to compromise the tools or the projects they manage.
• Specific Threats:
  • Project File Exploits: Injecting malicious code or data into project files through vulnerabilities in development tools.
  • Insecure Project Data Storage: Exposing sensitive project data due to insecure storage practices in development tools.
  • Tool Dependency Vulnerabilities: Exploiting vulnerabilities in third-party libraries used by development tools to compromise the tools or projects.

2.7 korlibs Libraries:

• Inferred Functionality: Low-level utilities, I/O, networking, math, collections, and other foundational functionalities used by Korge engine components.
• Security Implications:
  • Vulnerabilities in Underlying Libraries: Vulnerabilities in korlibs libraries directly impact the security of Korge, as these libraries are fundamental building blocks.
  • Dependency Management Risks: Improper dependency management or reliance on vulnerable versions of korlibs libraries could introduce security risks.
  • Supply Chain Risks: Compromise of korlibs libraries (e.g., through malicious commits or compromised package repositories) would directly compromise Korge.
• Specific Threats:
  • Third-Party Library Vulnerabilities: Exploiting known vulnerabilities in korlibs libraries.
  • Dependency Confusion/Substitution: Attackers could attempt to substitute malicious versions of korlibs libraries during the build process.
  • Supply Chain Attacks on korlibs: Compromising the development or distribution infrastructure of korlibs libraries to inject malicious code.

3. Architecture, Components, and Data Flow Inference

Based on the C4 diagrams and descriptions, we can infer the following about Korge's architecture and data flow:

• Modular Architecture: Korge is designed with a modular architecture, separating functionalities into distinct containers (Core Engine, Rendering Engine, Input Handling, etc.). This modularity can improve security by isolating potential vulnerabilities within specific components.
• Library-Based Foundation: Korge relies heavily on the korlibs libraries for low-level functionalities. This means the security of korlibs is paramount for Korge's overall security.
• Developer-Centric API: Korge provides APIs for game developers to interact with engine components. The security of these APIs and how developers use them is crucial.
• Multiplatform Support: Korge targets multiple platforms (desktop, web, mobile). This implies that security considerations must be addressed across different platform environments and their respective security models (e.g., browser sandboxing for web games, OS-level permissions for desktop/mobile).
• Build Process Dependency: The build process relies on Gradle, Kotlin Compiler, and potentially other tools. Security of the build pipeline and dependency management is critical to prevent supply chain attacks.
• Deployment Flexibility: Games built with Korge can be deployed in various ways (web, app stores, desktop stores). Deployment security depends on the chosen platform and distribution method.

Data Flow (Inferred):

1. Input Data: Player input (keyboard, mouse, touch, gamepad) flows into the Input Handling container.
2. Input Processing: The Input Handling container processes and validates input, then passes relevant input events to the Core Engine.
3. Game Logic Execution: The Core Engine executes game logic, potentially using input events, game state, and resources.
4. Rendering Commands: Based on game logic and scene data, the Core Engine sends rendering commands to the Rendering Engine.
5. Graphics Rendering: The Rendering Engine processes rendering commands and interacts with the underlying graphics API to render the game visuals.
6. Audio Playback: The Core Engine interacts with the Audio Engine to play sound effects and music.
7. UI Interaction: The UI System handles UI rendering and user interaction with UI elements, potentially interacting with the Input Handling and Core Engine.
8. Resource Loading: The Core Engine loads game assets (images, audio, data files) from storage, potentially using functionalities from korlibs Libraries.

This inferred data flow highlights critical points for security considerations, particularly around input processing, resource handling, and interactions between components.

4. Specific Security Recommendations for Korge

Based on the analysis, here are specific security recommendations tailored to the Korge project:

4.1 Input Validation and Sanitization:

• Recommendation: Implement robust input validation and sanitization within the Input Handling container. This should include:
  • Input Type Validation: Verify that input data conforms to expected types and formats.
  • Bounds Checking: Ensure input data does not exceed buffer limits to prevent buffer overflows.
  • Sanitization: Escape or sanitize input data before using it in any context where injection vulnerabilities are possible (e.g., UI rendering, resource paths - though resource paths should ideally be managed internally and not directly derived from user input).
• Actionable Mitigation:
  • Develop input validation functions within korge-input for different input types (text, numeric, etc.).
  • Integrate input validation into event handling mechanisms to ensure all input is checked before being processed by the Core Engine.
  • Document best practices for game developers on how to use Korge's input handling APIs securely and avoid common input-related vulnerabilities in their game logic.

4.2 Secure Resource Handling:

• Recommendation: Strengthen resource handling within the Core Engine and korlibs Libraries to prevent resource-related vulnerabilities. This includes:
  • Path Traversal Prevention: Implement strict path validation and sanitization when loading game assets to prevent access to files outside of allowed directories. Use secure file access APIs provided by korlibs.
  • Resource Limits: Implement mechanisms to limit the size and number of resources that can be loaded to prevent resource exhaustion attacks.
  • Secure Deserialization (If Applicable): If game data is serialized and deserialized, ensure secure deserialization practices are used to prevent deserialization vulnerabilities. Consider using safe serialization formats and libraries.
• Actionable Mitigation:
  • Develop secure resource loading APIs within korge-core that enforce path restrictions and resource limits.
  • Review and harden file I/O operations within korlibs to prevent path traversal vulnerabilities.
  • If using serialization, investigate and implement secure serialization practices using Kotlin serialization libraries or consider alternative data formats.

4.3 Shader Security:

• Recommendation: Address potential shader security risks within the Rendering Engine.
  • Shader Validation: If possible, implement shader validation or sanitization to detect potentially malicious shaders before compilation.
  • Sandboxing (If Feasible): Explore options for sandboxing shader execution to limit the impact of shader exploits.
  • Regular Updates of Graphics Drivers: Encourage users and developers to keep their graphics drivers updated to patch known shader-related vulnerabilities in drivers.
• Actionable Mitigation:
  • Investigate existing shader validation tools or techniques that can be integrated into korge-render.
  • Research the feasibility of shader sandboxing within the target graphics APIs (OpenGL, WebGL, etc.).
  • Include a recommendation in Korge documentation for developers to advise players to keep their graphics drivers updated.

4.4 Audio Security:

• Recommendation: Enhance audio processing security within the Audio Engine.
  • Secure Audio Decoding Libraries: Use well-vetted and regularly updated audio decoding libraries within korge-audio.
  • Buffer Overflow Prevention in Audio Processing: Review and harden audio processing code to prevent buffer overflows, especially in audio decoding and effects processing.
  • Input Validation for Audio Files (If Applicable): If Korge allows loading audio files from external sources (e.g., in development tools or game-specific features), implement validation to prevent processing of malformed or malicious audio files.
• Actionable Mitigation:
  • Audit and update audio decoding libraries used in korge-audio to ensure they are secure and up-to-date.
  • Conduct code review of audio processing code within korge-audio focusing on buffer overflow vulnerabilities.
  • If external audio file loading is supported, implement file format validation and potentially sandboxing for audio decoding.

4.5 UI Security (If Web-Based or Using Web Technologies):

• Recommendation: If the UI System uses web technologies for rendering, address potential XSS-like vulnerabilities.
  • Output Encoding/Escaping: Ensure proper output encoding or escaping of user-controlled data when rendering UI elements to prevent script injection.
  • Content Security Policy (CSP) (For Web Deployment): If deploying web games, implement Content Security Policy to mitigate XSS risks in the browser environment.
• Actionable Mitigation:
  • If korge-ui uses web technologies, implement robust output encoding/escaping mechanisms for UI rendering.
  • For web game deployments, provide guidance and tools for developers to implement CSP effectively.

4.6 Development Tool Security:

• Recommendation: Secure the Development Tools to prevent them from becoming a vulnerability vector for game projects.
  • Input Validation in Tools: Implement input validation in development tools to prevent project file exploits.
  • Secure Project Data Storage: Ensure project data is stored securely, avoiding storing sensitive information in plaintext if possible.
  • Dependency Scanning for Tools: Include dependency scanning for the development tools themselves in the build process to identify and address vulnerabilities in tool dependencies.
• Actionable Mitigation:
  • Conduct security review and penetration testing of korge-tools to identify potential vulnerabilities.
  • Implement input validation and sanitization in korge-tools for project file processing and user input.
  • Integrate dependency scanning into the build process for korge-tools using tools like OWASP Dependency-Check.

4.7 korlibs Library Security:

• Recommendation: Maintain a strong focus on the security of korlibs Libraries.
  • Regular Dependency Updates: Keep korlibs libraries and their dependencies up-to-date to patch known vulnerabilities.
  • Dependency Scanning for korlibs: Implement dependency scanning for korlibs libraries in the build process.
  • Security Audits of korlibs: Conduct regular security audits of korlibs libraries, especially critical components.
  • Supply Chain Security Measures: Implement measures to protect the korlibs supply chain, such as code signing, secure build pipelines, and secure package repositories.
• Actionable Mitigation:
  • Automate dependency updates for korlibs libraries using dependency management tools.
  • Integrate dependency scanning into the CI/CD pipeline for korlibs using tools like OWASP Dependency-Check.
  • Plan for periodic security audits of korlibs libraries, potentially engaging external security experts.
  • Implement code signing for korlibs library releases to ensure integrity and authenticity.

4.8 Build Process Security:

• Recommendation: Enhance the security of the Korge build process.
  • Automated Security Scanning in CI/CD: Implement SAST and dependency scanning in the CI/CD pipeline for Korge engine code (as already recommended in the Security Design Review).
  • Secure Build Environment: Harden the build server environment and ensure access control is properly configured.
  • Artifact Integrity Checks: Implement artifact integrity checks (e.g., checksums, signatures) for build artifacts to ensure they are not tampered with during distribution.
• Actionable Mitigation:
  • Integrate SAST tools (e.g., SonarQube, Semgrep) and dependency scanning tools (e.g., OWASP Dependency-Check) into the GitHub Actions CI/CD pipeline.
  • Follow security best practices for hardening GitHub Actions runners and securing the build environment.
  • Implement artifact signing for Korge engine releases to ensure integrity.

4.9 Security Guidelines for Game Developers:

• Recommendation: Provide comprehensive security guidelines and best practices for game developers using Korge to build games (as already recommended in the Security Design Review).
  • Input Validation in Game Logic: Emphasize the importance of input validation in game-specific logic to prevent game-specific cheating and exploits.
  • Secure Data Handling: Provide guidance on secure storage and handling of game data, especially sensitive user data if games collect such data.
  • Network Security (If Applicable): If games use networking, provide guidance on secure network communication and authentication.
  • Vulnerability Reporting Process: Clearly communicate the process for reporting security vulnerabilities in Korge and in games built with Korge.
• Actionable Mitigation:
  • Create a dedicated security section in the Korge documentation with security guidelines and best practices for game developers.
  • Provide code examples and templates demonstrating secure coding practices in Korge games.
  • Establish a clear and accessible vulnerability reporting process for both Korge engine vulnerabilities and vulnerabilities in games built with Korge.

5. Actionable and Tailored Mitigation Strategies

The actionable mitigation strategies are embedded within each recommendation in section 4. To summarize and further emphasize actionability, here's a consolidated list of key actions for the Korge development team:

1. Implement Automated Security Scanning in CI/CD: Integrate SAST and dependency scanning tools into the GitHub Actions pipeline for both Korge engine and korlibs libraries.
2. Establish Vulnerability Reporting Process: Create a clear and public process for reporting security vulnerabilities, including a dedicated email address or security issue tracker.
3. Conduct Regular Security Audits: Plan for periodic security audits of Korge engine and korlibs libraries, starting with critical components like Core Engine, Rendering Engine, and korlibs core libraries.
4. Develop Security Guidelines for Game Developers: Create a comprehensive security section in the Korge documentation with best practices and code examples.
5. Strengthen Input Validation: Implement robust input validation and sanitization within the korge-input container and provide APIs for developers to use securely.
6. Enhance Resource Handling Security: Harden resource loading and handling within korge-core and korlibs to prevent path traversal and resource exhaustion.
7. Address Shader Security: Investigate shader validation and sandboxing options for korge-render.
8. Improve Audio Security: Audit and update audio decoding libraries and harden audio processing code in korge-audio.
9. Secure Development Tools: Conduct security review and penetration testing of korge-tools and implement input validation and dependency scanning.
10. Focus on korlibs Security: Prioritize security for korlibs libraries through regular updates, dependency scanning, security audits, and supply chain security measures.
11. Implement Artifact Signing: Sign Korge engine releases to ensure integrity and authenticity.

These recommendations and actionable strategies are tailored to the Korge project, focusing on specific components and functionalities inferred from the provided documentation. By implementing these mitigations, the Korge development team can significantly enhance the security posture of the engine and build a more secure ecosystem for game developers and players.