threat-modeling.md

Threat Model Analysis for permissions-dispatcher/permissionsdispatcher

Threat: Threat 1: Permission Bypass via Reflection/Runtime Manipulation (Targeting Generated Code)

• Description: A malicious application on the same device uses reflection (Java's ability to inspect and modify code at runtime) or other advanced techniques (e.g., hooking frameworks like Frida or Xposed) to specifically target the PermissionsDispatcher-generated code. The attacker's goal is to bypass permission checks enforced by the library. They might attempt to:
  • Directly invoke methods annotated with @NeedsPermission without going through the PermissionsDispatcher request flow.
  • Modify the return values of internal PermissionsDispatcher helper methods (e.g., those that check permission status) to falsely indicate that a permission has been granted.
  • Interfere with the logic within the generated onRequestPermissionsResult method to manipulate the outcome of a permission request.
• Impact: The malicious application gains unauthorized access to protected resources or functionality, completely circumventing the Android permission system as managed by PermissionsDispatcher. This can lead to severe data breaches, unauthorized actions, and privilege escalation.
• Affected Component: The entire PermissionsDispatcher-generated class (e.g., MainActivityPermissionsDispatcher), including all generated methods and internal logic. This is a direct attack on the library's output.
• Risk Severity: Critical
• Mitigation Strategies:
  • Developer:
    • Use code obfuscation (ProGuard/R8) to make reflection and code modification more difficult. This is a deterrent, not a foolproof solution.
    • Consider implementing the most sensitive permission-related logic in native code (using the Android NDK). Native code is significantly harder to reverse engineer and manipulate at runtime. This moves the critical logic outside of the direct reach of PermissionsDispatcher's generated code.
    • Implement runtime integrity checks (e.g., checking the application's signature or checksum) to detect if the application's code (including the generated code) has been tampered with. This is a complex mitigation to implement reliably.
    • Crucially, do not rely solely on PermissionsDispatcher for security-critical operations. Always have additional layers of defense. For example, if accessing sensitive data, encrypt it at rest and in transit, and use secure authentication mechanisms.
  • User:
    • Only install applications from trusted sources (e.g., the official Google Play Store).
    • Be wary of applications that request an excessive number of permissions.
    • Use a reputable mobile security solution that can detect and potentially block runtime manipulation attempts.

Threat: Threat 2: PermissionsDispatcher Library Vulnerability (Exploitable Flaw)

• Description: A security vulnerability exists within the PermissionsDispatcher library itself. This could be a flaw in:
  • The code generation process (e.g., an injection vulnerability or a logic error that leads to incorrect permission handling).
  • The runtime library's handling of permission requests or responses.
  • A bypass of the intended permission checks due to an unforeseen edge case or a design flaw.
• Impact: Depending on the specific vulnerability, the impact could range from unauthorized access to specific resources to arbitrary code execution and complete device compromise. This threat affects all applications using the vulnerable version of PermissionsDispatcher.
• Affected Component: The entire PermissionsDispatcher library (all modules, including the annotation processor and the runtime library). This is a vulnerability within the library itself.
• Risk Severity: Critical
• Mitigation Strategies:
  • Developer:
    • Keep PermissionsDispatcher updated to the latest version. This is the primary and most effective mitigation. Library maintainers will release patches to address security vulnerabilities.
    • Actively monitor security advisories and mailing lists related to PermissionsDispatcher and Android security in general. Be prepared to update quickly when a vulnerability is disclosed.
    • If a vulnerability is discovered and a patch is not immediately available, strongly consider temporarily disabling the features that rely on PermissionsDispatcher, or switch to a different (and currently secure) permission handling approach until a fix is released.
    • Contribute to the security of the library by reporting any suspected vulnerabilities to the maintainers and participating in code reviews or security audits, if possible.
  • User:
    • Keep your device's operating system and all applications updated to the latest versions. This ensures that you receive security patches for both the OS and the applications you use.
    • Use a reputable mobile security solution that can detect and block known exploits, including those that might target vulnerabilities in libraries like PermissionsDispatcher.

Threat: Threat 3: Incomplete Permission Handling (Missing @OnPermissionDenied)

• Description: The developer uses @NeedsPermission but fails to implement a corresponding @OnPermissionDenied method. When the user denies the permission, the application does not handle the denial gracefully, which may lead to crash.
• Impact: Application instability, crashes.
• Affected Component: Methods annotated with @NeedsPermission and the absence of a corresponding @OnPermissionDenied handler. The generated onRequestPermissionsResult method in the PermissionsDispatcher class.
• Risk Severity: High
• Mitigation Strategies:
  • Developer:
    • Always implement an @OnPermissionDenied method for every @NeedsPermission annotation.
    • Within @OnPermissionDenied, handle the denial gracefully.
    • Thoroughly test the application's behavior when permissions are denied.
  • User:
    • If an application crashes or behaves unexpectedly after denying a permission, report the issue to the developer.