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Mitigation Strategies Analysis for jbogard/mediatr

Mitigation Strategy: Strict Request Validation (MediatR Focused)

  • Mitigation Strategy: Strict Request Validation (MediatR Focused)
  • Description:
    1. Define Request Objects with Validation: For every MediatR request (Command or Query), create dedicated classes and embed validation logic directly within or alongside these request objects. Utilize validation attributes or libraries (like FluentValidation in .NET) to define rules for each property of the request.
    2. Implement Validation as a MediatR Pipeline Behavior: Create a MediatR pipeline behavior specifically designed for validation. This behavior will intercept each request before it reaches the handler.
    3. Validation Behavior Execution: The validation behavior will:
      • Receive the incoming MediatR request.
      • Execute the validation rules defined for the request object.
      • If validation fails, throw a ValidationException within the behavior, preventing the request from reaching the handler. This exception should be handled to return appropriate error responses.
      • If validation succeeds, allow the request to proceed through the MediatR pipeline to the intended handler.
  • List of Threats Mitigated:
    • Injection Attacks (High Severity): SQL Injection, Cross-Site Scripting (XSS), Command Injection. MediatR request validation prevents malicious data from entering the application via MediatR requests.
    • Data Integrity Issues (Medium Severity): Ensures that only valid data is processed by MediatR handlers, maintaining data consistency.
    • Business Logic Errors (Medium Severity): Reduces errors caused by invalid input data reaching MediatR handlers, leading to more stable application behavior.
  • Impact:
    • Injection Attacks: High Risk Reduction. Directly mitigates injection vulnerabilities by validating MediatR request inputs.
    • Data Integrity Issues: High Risk Reduction. Ensures data processed through MediatR is valid.
    • Business Logic Errors: Medium Risk Reduction. Improves the robustness of MediatR request handling.
  • Currently Implemented:
    • Validation pipeline behavior is implemented in the API project (API/Behaviors/ValidationBehavior.cs).
    • FluentValidation is used for request object validation. Validation rules are defined alongside request objects in the Application project (e.g., Application/Commands/CreateUserCommandValidator.cs).
  • Missing Implementation:
    • Ensure all Commands and Queries in the Application project have corresponding validator classes.
    • Review and ensure consistent application of validation rules across all MediatR requests.

Mitigation Strategy: Request Type Whitelisting (MediatR Focused)

  • Mitigation Strategy: Request Type Whitelisting (MediatR Focused)
  • Description:
    1. Define Allowed MediatR Request Types: Create a configuration or registry that explicitly lists all MediatR request types (full class names of Commands and Queries) that the application is designed to process.
    2. Implement Whitelisting Behavior in MediatR Pipeline: Develop a MediatR pipeline behavior that acts as a whitelist filter. This behavior should be placed early in the pipeline.
    3. Whitelisting Behavior Logic: The behavior will:
      • Receive the incoming MediatR request.
      • Check if the type of the request (its class name) is present in the pre-defined whitelist of allowed MediatR request types.
      • If the request type is not whitelisted, throw an InvalidRequestTypeException within the behavior, preventing further processing by MediatR.
      • If the request type is whitelisted, allow the request to proceed to the next behavior and eventually to the handler.
  • List of Threats Mitigated:
    • Unexpected Request Handling (Medium Severity): Prevents the MediatR pipeline from processing unintended or potentially malicious request types that are not part of the application's designed functionality.
    • Resource Exhaustion (Low to Medium Severity): Can help prevent resource exhaustion by blocking processing of a flood of unknown or invalid MediatR request types.
  • Impact:
    • Unexpected Request Handling: Medium Risk Reduction. Reduces the risk of processing unforeseen MediatR request types.
    • Resource Exhaustion: Low to Medium Risk Reduction. Provides a degree of protection against resource exhaustion from invalid requests.
  • Currently Implemented:
    • No request type whitelisting is currently implemented within the MediatR pipeline.
  • Missing Implementation:
    • Implement a configuration mechanism to store the whitelist of allowed MediatR request types (e.g., in appsettings.json).
    • Create a WhitelistBehavior and register it as an early behavior in the MediatR pipeline in the API project's startup configuration (Startup.cs or Program.cs).

Mitigation Strategy: Behavior-Based Authorization (MediatR Focused)

  • Mitigation Strategy: Behavior-Based Authorization (MediatR Focused)
  • Description:
    1. Define Authorization Policies: Establish authorization policies that define access control rules for different actions or resources within the application. These policies can be based on user roles, permissions, or claims.
    2. Implement Authorization as a MediatR Pipeline Behavior: Create a MediatR pipeline behavior specifically for authorization. This behavior will be executed before request handlers.
    3. Authorization Behavior Logic: The behavior will:
      • Identify the current user's identity and roles/permissions (typically from the application's authentication context).
      • Determine the required authorization policy for the incoming MediatR request type (e.g., based on request type name or associated attributes).
      • Evaluate the authorization policy against the current user's permissions.
      • If authorization fails, throw an UnauthorizedAccessException or a custom authorization exception within the behavior, preventing the request from reaching the handler. This exception should be handled to return HTTP 403 Forbidden or 401 Unauthorized responses.
      • If authorization succeeds, allow the MediatR request to proceed to the handler.
    4. Policy Mapping to MediatR Requests: Establish a clear mapping between MediatR request types (Commands and Queries) and the authorization policies that govern access to them. This mapping can be configured or defined using attributes.
  • List of Threats Mitigated:
    • Unauthorized Access (High Severity): Prevents unauthorized users from executing MediatR requests that access sensitive data or perform restricted actions.
    • Privilege Escalation (High Severity): Reduces the risk of users gaining access to functionalities or data they are not authorized to access through MediatR requests.
    • Data Breaches (High Severity): By controlling access to MediatR request handlers, behavior-based authorization helps prevent data breaches caused by unauthorized actions.
  • Impact:
    • Unauthorized Access: High Risk Reduction. Effectively controls access to application functionalities exposed through MediatR.
    • Privilege Escalation: High Risk Reduction. Limits the potential for privilege escalation attacks via MediatR requests.
    • Data Breaches: High Risk Reduction. Contributes significantly to preventing data breaches related to unauthorized MediatR actions.
  • Currently Implemented:
    • Basic authorization checks are implemented directly within some request handlers for specific commands and queries. This is inconsistent and not behavior-driven.
  • Missing Implementation:
    • Create a dedicated AuthorizationBehavior and register it in the MediatR pipeline.
    • Migrate existing handler-level authorization checks to this behavior-based approach for consistency and centralized authorization logic within the MediatR pipeline.
    • Define comprehensive authorization policies and establish a clear mapping between these policies and MediatR request types.

Mitigation Strategy: Secure Behavior Implementation (MediatR Focused)

  • Mitigation Strategy: Secure Behavior Implementation (MediatR Focused)
  • Description:
    1. Security Focus in Behavior Development: When developing MediatR pipeline behaviors, prioritize security considerations throughout the development lifecycle.
    2. Security Code Reviews for Behaviors: Conduct specific security code reviews focused on all MediatR pipeline behaviors. Look for vulnerabilities within the behaviors themselves, such as:
      • Input validation weaknesses in behaviors.
      • Authorization flaws in authorization behaviors.
      • Unintentional logging of sensitive data within behaviors.
      • Error handling issues in behaviors that might expose information.
      • Vulnerabilities introduced by dependencies used within behaviors.
    3. Principle of Least Privilege for Behaviors: Design behaviors to operate with the minimum necessary permissions and access rights. Avoid granting behaviors broader permissions than they strictly require to perform their function within the MediatR pipeline.
    4. Security Testing of Behaviors: Implement unit and integration tests specifically designed to test the security aspects of MediatR behaviors. Test for:
      • Correct authorization enforcement by authorization behaviors.
      • Robust handling of invalid inputs by validation behaviors.
      • Secure error handling within all behaviors.
  • List of Threats Mitigated:
    • Vulnerabilities in MediatR Behaviors (High Severity): Vulnerabilities in behaviors can affect all requests processed by the MediatR pipeline, potentially leading to widespread security issues.
    • Data Leaks through Behaviors (Medium Severity): Insecurely implemented behaviors could unintentionally log or expose sensitive information.
    • Authorization Bypass due to Behavior Flaws (High Severity): Flaws in authorization behaviors can lead to complete bypass of access controls within the MediatR pipeline.
  • Impact:
    • Vulnerabilities in MediatR Behaviors: High Risk Reduction. Proactive security measures in behavior development minimize the risk of introducing vulnerabilities into the MediatR pipeline.
    • Data Leaks through Behaviors: Medium Risk Reduction. Secure coding and reviews reduce the chance of unintentional data leaks from MediatR behaviors.
    • Authorization Bypass due to Behavior Flaws: High Risk Reduction. Rigorous testing and reviews of authorization behaviors ensure proper access control within MediatR.
  • Currently Implemented:
    • General code reviews are conducted, but security-specific reviews focused on MediatR behaviors are not a standard practice.
    • Unit tests exist for some behaviors, but security-focused test cases are not consistently included for MediatR behaviors.
  • Missing Implementation:
    • Incorporate security-focused code reviews as a mandatory step for all MediatR pipeline behaviors.
    • Develop and implement security-specific test cases for behaviors, especially for authorization and validation behaviors within the MediatR pipeline.
    • Establish secure coding guidelines specifically for developing MediatR behaviors and provide training to developers on these guidelines.