attack-surface.md

Attack Surface Analysis for baseflow/flutter-permission-handler

Attack Surface: 1. Over-Requesting Permissions

• Description: The application requests more permissions than are strictly necessary for its core functionality.
• How flutter-permission-handler Contributes: The plugin provides an easy-to-use interface for requesting a wide variety of permissions, making it simpler for developers to request excessive permissions. It doesn't enforce any restrictions on which permissions can be requested.
• Example: A simple flashlight app requests access to the user's contacts, location, and microphone, in addition to the camera.
• Impact:
  • Expanded attack surface: If the app is compromised, the attacker gains access to all granted permissions.
  • User distrust.
• Risk Severity: High
• Mitigation Strategies:
  • Developer:
    • Strictly adhere to the principle of least privilege.
    • Conduct thorough code reviews.
    • Document the justification for each requested permission.
    • Use automated tools to identify unused permissions.
  • User:
    • Be cautious about granting permissions to apps.
    • Review app permissions regularly in device settings.

Attack Surface: 2. Incorrect Handling of Permission Status

• Description: The application logic incorrectly interprets or handles the various permission statuses (granted, denied, permanently denied, restricted, limited).
• How flutter-permission-handler Contributes: The plugin provides methods to check the current status of a permission, but it's the developer's responsibility to correctly interpret and handle these statuses.
• Example: An app assumes that a permission is granted if the status is not "permanently denied," failing to account for the "denied" or "restricted" states.
• Impact:
  • Functionality bypass: The app may attempt to perform actions that require a permission even when it hasn't been granted.
  • Application crashes.
  • Data leaks (in edge cases).
• Risk Severity: High
• Mitigation Strategies:
  • Developer:
    • Thoroughly test all code paths that handle permission statuses.
    • Use unit tests to specifically cover each possible permission state.
    • Ensure graceful handling of all permission denial scenarios.
    • Always explicitly check the status before attempting to use a protected resource.
  • User: (Limited direct mitigation)
    • Report any unexpected app behavior related to permissions.

Attack Surface: 3. Bypassing Permission Checks

• Description: Flaws in the application logic allow access to protected resources or functionality without properly checking or enforcing the required permissions, circumventing the flutter-permission-handler's intended purpose.
• How flutter-permission-handler Contributes: The plugin provides the tools to check and request permissions, but it cannot prevent developers from not using those tools correctly or from introducing logic errors that bypass the checks.
• Example: A photo editing app writes to external storage before checking the storage permission, or even if the permission is denied.
• Impact:
  • Unauthorized access to sensitive data or functionality.
  • Violation of user privacy.
  • Potential for data corruption or loss.
• Risk Severity: Critical
• Mitigation Strategies:
  • Developer:
    • Implement robust input validation and error handling.
    • Ensure that all code paths that access protected resources always check the permission status immediately before accessing the resource.
    • Conduct thorough code reviews and security audits.
    • Use static analysis tools.
  • User: (No direct mitigation)

Attack Surface: 4. Plugin Implementation Vulnerabilities

• Description: Vulnerabilities exist within the flutter-permission-handler plugin's own code (particularly its native Android/iOS implementations) or in its dependencies.
• How flutter-permission-handler Contributes: This is a direct vulnerability within the plugin itself.
• Example: A buffer overflow vulnerability in the plugin's native Android code.
• Impact:
  • Potentially severe, ranging from denial of service to arbitrary code execution.
  • Could allow attackers to bypass permission checks entirely.
• Risk Severity: Critical (but generally less likely than application-level misuse)
• Mitigation Strategies:
  • Developer:
    • Keep the flutter-permission-handler plugin updated to the latest version.
    • Monitor security advisories.
    • Use dependency scanning tools.
  • User:
    • Keep your device's operating system and apps updated.