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attack-surface.md

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Attack Surface Analysis for ocornut/imgui

Attack Surface: Buffer Overflows in Text Inputs

  • Description: Vulnerabilities arising from writing beyond the allocated memory buffer when handling text input within ImGui, potentially leading to crashes or code execution.
  • ImGui Contribution: ImGui's ImGui::InputText and similar functions rely on application-provided buffers. Incorrect buffer sizing or lack of input length limits when using these ImGui functions directly leads to this vulnerability.
  • Example: An attacker provides a string of 2000 characters to an ImGui::InputText field, while the application buffer is only 256 bytes. This overwrites adjacent memory regions due to ImGui writing beyond the buffer.
  • Impact: Application crash, denial of service, potential arbitrary code execution if the overflow corrupts critical data or control flow.
  • Risk Severity: High
  • Mitigation Strategies:
    • Strict Buffer Size Management: Always ensure buffers passed to ImGui::InputText and related functions are adequately sized for the maximum expected input, including a safety margin.
    • Utilize Input Length Limits: Employ ImGui input flags like ImGuiInputTextFlags_CharsMaxLength to enforce a maximum character limit directly within the ImGui input field, preventing excessively long inputs from being processed by ImGui in the first place.
    • Pre-Input Validation (Application Side): Before passing buffers to ImGui input functions, validate the expected maximum input length and allocate buffers accordingly.

Attack Surface: Format String Vulnerabilities (in Text Display)

  • Description: Exploiting format string functions through user-controlled input used in ImGui's text display, potentially allowing attackers to read from or write to arbitrary memory.
  • ImGui Contribution: ImGui's text display functions like ImGui::Text, ImGui::TextColored, and ImGui::TextWrapped can become vulnerable if application code directly uses unsanitized user-provided strings as format strings within these ImGui functions.
  • Example: Application code uses ImGui::Text(userInput) where userInput is directly taken from user input and contains format specifiers like "%s%n". This allows an attacker to potentially write to arbitrary memory locations via ImGui's text rendering.
  • Impact: Information disclosure (reading memory), denial of service, potential arbitrary code execution (writing to memory).
  • Risk Severity: High
  • Mitigation Strategies:
    • Avoid User Input as Format Strings: Never directly use user-controlled input as the format string argument in ImGui's text display functions.
    • Safe String Formatting Practices: Use safe string formatting methods that inherently prevent format string vulnerabilities. Construct the display strings programmatically instead of relying on format specifiers with user input.
    • Input Sanitization (Format Specifier Removal): If user input must be displayed in a formatted way, rigorously sanitize the input to remove or escape all format specifiers (e.g., %, s, n, etc.) before passing it to ImGui's text functions.

Attack Surface: Vulnerabilities in Custom Backend Implementations

  • Description: Security flaws introduced within the custom rendering or input handling backend code that is necessary to integrate ImGui into a specific application and platform.
  • ImGui Contribution: ImGui is backend-agnostic and requires custom backend implementations for rendering and input. Vulnerabilities in these required backend components are directly related to the security of an ImGui-based application.
  • Example: A custom OpenGL backend for ImGui has a buffer overflow vulnerability in its vertex buffer management, triggered by specific ImGui rendering commands. This vulnerability is directly exploitable because the backend is a necessary part of using ImGui.
  • Impact: Varies greatly depending on the backend vulnerability. Can range from application crashes and denial of service to arbitrary code execution if backend vulnerabilities allow memory corruption or control flow hijacking.
  • Risk Severity: High to Critical (depending on the nature and exploitability of backend vulnerabilities)
  • Mitigation Strategies:
    • Secure Backend Development Practices: Adhere to strict secure coding practices when developing custom ImGui backends. Focus on memory safety, proper resource management, and secure API usage.
    • Thorough Code Reviews and Security Testing: Conduct rigorous code reviews and security testing specifically targeting the custom backend implementations.
    • Leverage Secure and Well-Vetted Libraries: Utilize secure and well-established libraries and APIs for backend operations (e.g., robust and updated graphics libraries, secure input handling mechanisms).
    • Regular Updates and Patching of Backend Dependencies: Keep all backend libraries and dependencies up-to-date with the latest security patches to mitigate known vulnerabilities in underlying components.

Attack Surface: Vulnerabilities in Custom Widgets or Extensions

  • Description: Security flaws introduced within custom ImGui widgets or extensions that are created to extend ImGui's base functionality.
  • ImGui Contribution: ImGui's extensibility encourages the creation of custom widgets. Insecurely developed custom widgets directly introduce vulnerabilities into applications that utilize these extensions of ImGui.
  • Example: A custom ImGui widget designed to display images has a buffer overflow vulnerability in its image loading or rendering code. This vulnerability is directly exploitable through the custom ImGui widget within the application.
  • Impact: Varies depending on the vulnerability within the custom widget. Can range from application crashes and denial of service to arbitrary code execution if widget vulnerabilities allow memory corruption or control flow hijacking.
  • Risk Severity: High to Critical (depending on the nature and exploitability of vulnerabilities in custom widgets)
  • Mitigation Strategies:
    • Secure Custom Widget Development Lifecycle: Implement a secure development lifecycle for custom ImGui widgets, including secure coding guidelines, threat modeling, and security testing.
    • Rigorous Code Reviews and Security Audits: Conduct thorough code reviews and security audits specifically for all custom ImGui widgets and extensions.
    • Input Validation and Sanitization within Widgets: Ensure custom widgets rigorously validate and sanitize any user input they handle, preventing injection vulnerabilities within the widget itself.
    • Memory Safety and Resource Management in Widgets: Pay meticulous attention to memory safety and resource management within custom widget code, particularly in rendering, data handling, and external library interactions.