mitigations.md

Mitigation Strategies Analysis for permissions-dispatcher/permissionsdispatcher

Mitigation Strategy: Principle of Least Privilege Enforcement with PermissionsDispatcher

• Description:

  1. Justify Permissions in @NeedsPermission: For every method annotated with @NeedsPermission, developers must explicitly document in code comments or a separate document why that specific permission is necessary for the functionality triggered by that method. This justification should be reviewed during code reviews to ensure necessity and prevent over-permissioning.
  2. Code Path Analysis for @NeedsPermission: During development and code reviews, analyze the code executed within methods annotated with @NeedsPermission. Verify that the requested permission is genuinely used within these code paths and not requested superfluously.
  3. Minimize Permission Scope in @NeedsPermission: When using @NeedsPermission, always request the least privileged permission that still allows the functionality to work. For example, if only read access to external storage is needed, use READ_EXTERNAL_STORAGE instead of WRITE_EXTERNAL_STORAGE.
  4. Regular Review of @NeedsPermission Annotations: Periodically (e.g., every feature release or major update), review all usages of @NeedsPermission annotations in the codebase. Re-evaluate if the requested permissions are still necessary and if the justifications remain valid. Remove @NeedsPermission annotations and associated permissions if they are no longer required.

  • List of Threats Mitigated:

    • Over-permissioning due to simplified permission requests (High Severity): PermissionsDispatcher's ease of use can inadvertently lead developers to request more permissions than strictly needed, increasing the application's attack surface.
    • Accidental Privilege Escalation (Medium Severity): If @NeedsPermission is misused or applied incorrectly, it could unintentionally grant access to sensitive resources or functionalities beyond what is intended, potentially leading to privilege escalation if exploited.

  • Impact:

    • Over-permissioning: High reduction in risk. By enforcing least privilege within PermissionsDispatcher usage, the attack surface is minimized, reducing the potential impact of a compromise.
    • Accidental Privilege Escalation: Medium reduction in risk. Careful review and justification of @NeedsPermission usage reduces the likelihood of unintended privilege grants.

  • Currently Implemented:

    • Partially implemented. Code reviews are conducted, and developers are generally encouraged to request minimal permissions. However, formal justification documentation for @NeedsPermission usage and dedicated reviews of these annotations are not consistently enforced.

  • Missing Implementation:

    • Mandatory documentation of permission justifications for each @NeedsPermission annotation.
    • Specific code review checklist items focusing on the necessity and scope of permissions requested via @NeedsPermission.
    • Automated tooling or scripts to help identify potentially over-permissioned @NeedsPermission usages (e.g., static analysis to check if the permission is actually used in the annotated method).
    • Scheduled reviews of @NeedsPermission annotations as part of the release process.

Mitigation Strategy: Code Review of PermissionsDispatcher Implementation Details

• Description:

  1. Focus on Annotation Usage: During code reviews, specifically scrutinize the correct and secure usage of PermissionsDispatcher annotations: @NeedsPermission, @OnShowRationale, @OnPermissionDenied, and @OnNeverAskAgain. Ensure developers understand the intended behavior of each annotation and are using them as designed.
  2. Review Permission Result Handling: Carefully examine the implementation of methods annotated with @OnPermissionDenied and @OnNeverAskAgain. Verify that these methods gracefully handle permission denial scenarios, provide appropriate user feedback, and prevent application errors or security vulnerabilities in these situations. Ensure sensitive operations are not attempted if permissions are denied.
  3. Inspect Rationale Display Logic (@OnShowRationale): Review the logic within methods annotated with @OnShowRationale. Confirm that the rationale provided to the user is clear, concise, and accurately explains why the permission is needed. Ensure the rationale display mechanism itself does not introduce any vulnerabilities (e.g., displaying sensitive information).
  4. Verify Generated Code Understanding: While developers don't directly write the generated code by PermissionsDispatcher, ensure they understand how PermissionsDispatcher works under the hood. This includes understanding how the annotations are processed and how permission requests are initiated and handled by the generated code. This understanding helps in debugging and identifying potential issues related to PermissionsDispatcher's behavior.

  • List of Threats Mitigated:

    • Misconfiguration/Misuse of PermissionsDispatcher Annotations (Medium Severity): Incorrect or insecure usage of PermissionsDispatcher annotations can lead to unexpected permission behavior, bypasses of permission checks, or insecure handling of permission denial scenarios.
    • Logic Errors in Permission Handling due to misunderstanding PermissionsDispatcher (Medium Severity): If developers misunderstand how PermissionsDispatcher works or how to correctly implement the annotated methods, it can lead to logic errors in permission handling, potentially causing application crashes, denial-of-service, or information leaks in permission denial paths.

  • Impact:

    • Misconfiguration/Misuse of PermissionsDispatcher Annotations: Medium reduction in risk. Focused code reviews can catch and prevent common implementation errors related to annotation usage.
    • Logic Errors in Permission Handling: Medium reduction in risk. Thorough review of permission handling logic within PermissionsDispatcher's context minimizes the risk of errors leading to security issues.

  • Currently Implemented:

    • Partially implemented. Code reviews are conducted, but specific focus on PermissionsDispatcher implementation details and annotation usage is inconsistent. Reviewers may not always have deep knowledge of PermissionsDispatcher's nuances.

  • Missing Implementation:

    • Formalized code review checklist specifically for PermissionsDispatcher implementation details and annotation usage.
    • Training materials or documentation for code reviewers on secure PermissionsDispatcher review practices.
    • Potentially, static analysis rules or linters to automatically detect common misuses of PermissionsDispatcher annotations.