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Mitigation Strategies Analysis for gorilla/mux

Mitigation Strategy: Principle of Least Privilege for Routes

Description:

  • Step 1: Route Inventory: Create a comprehensive list of all routes defined in your gorilla/mux router by reviewing your code where mux.HandleFunc, mux.Handle, mux.PathPrefix, and similar functions are used.
  • Step 2: Route Specificity Analysis: For each route, analyze its pattern defined in mux. Identify routes that use overly broad patterns like /* or very generic path variable names within mux route definitions.
  • Step 3: Refine Route Patterns: Modify broad route patterns in mux to be as specific as possible. For example, instead of /api/*, define specific routes like /api/users, /api/products, /api/orders using mux's routing functions. Replace generic path variables in mux routes with more descriptive ones, e.g., /users/{userID} instead of /resource/{id} if the ID refers to a user, within mux path definitions.
  • Step 4: Remove Unnecessary Catch-Alls: Eliminate catch-all routes (/*) defined in mux if they are not absolutely necessary. If a catch-all is required (e.g., for serving static files or a single-page application), ensure it is handled by a dedicated, secure handler registered with mux that performs strict input validation and access control.
  • Step 5: Regular Route Review: Establish a process for regularly reviewing and updating route definitions in mux as the application evolves. This ensures that routes remain aligned with the principle of least privilege and that no unintended endpoints are exposed through mux's routing.

List of Threats Mitigated:

  • Unauthorized Access (Severity: High): Broad routes defined in mux can unintentionally expose sensitive endpoints.
  • Information Disclosure (Severity: Medium): Overly permissive routes in mux might inadvertently reveal more data than intended.
  • Attack Surface Increase (Severity: Medium): A larger number of exposed routes defined in mux increases the overall attack surface.

Impact:

  • Unauthorized Access: High reduction in risk. By limiting route scope in mux, you directly reduce the chances of unauthorized access.
  • Information Disclosure: Medium reduction in risk. More specific routes in mux help in better controlling data accessibility.
  • Attack Surface Increase: Medium reduction in risk. Reducing overly broad routes in mux effectively shrinks the attack surface.

Currently Implemented:

Partially implemented in the core API routes (/api/v1/users, /api/v1/products, etc.) which are defined with specific paths and parameters using mux.

Missing Implementation:

Legacy routes under /legacy/* are still using a broad path prefix in mux and need to be reviewed and made more specific. Also, the admin panel routes under /admin/* defined in mux could be further refined instead of using a single prefix.

Mitigation Strategy: Explicit Route Definitions

Description:

  • Step 1: Minimize Regex Usage: Review route definitions in mux for heavy reliance on complex regular expressions. Identify routes where regex is used for simple pattern matching that could be achieved with standard mux path syntax.
  • Step 2: Simplify Regex (If Necessary): If regular expressions are necessary in mux routes, strive to make them as simple and readable as possible. Avoid overly complex or nested regex patterns that are difficult to understand and audit within mux route definitions.
  • Step 3: Prefer Concrete Paths: Whenever feasible, define routes in mux using concrete paths and path variables instead of relying on regex for path segment matching. For example, use /users/{id:[0-9]+} in mux instead of /users/([0-9]+).
  • Step 4: Thorough Regex Testing: If complex regex in mux is unavoidable, rigorously test the regex patterns with various inputs, including edge cases and potentially malicious inputs, to ensure they behave as expected and do not introduce vulnerabilities like ReDoS when used in mux routes.
  • Step 5: Code Review for Regex Routes: Pay extra attention to code reviews for routes in mux that use regular expressions. Ensure that the regex patterns are well-understood by the reviewers and that their security implications are considered in the context of mux routing.

List of Threats Mitigated:

  • Regular Expression Denial of Service (ReDoS) (Severity: High): Complex or poorly written regex in mux routes can be vulnerable to ReDoS attacks.
  • Route Bypass (Severity: Medium): Subtle errors in complex regex patterns in mux routes can lead to unintended route matching.
  • Maintainability Issues (Severity: Medium): Complex regex routes in mux are harder to understand, maintain, and audit.

Impact:

  • Regular Expression Denial of Service (ReDoS): High reduction in risk. Simplifying or avoiding complex regex in mux directly reduces ReDoS risk.
  • Route Bypass: Medium reduction in risk. Explicit routes in mux are less prone to unintended matching.
  • Maintainability Issues: Medium reduction in risk. Simpler mux routes are easier to understand and maintain.

Currently Implemented:

Mostly implemented. The project generally uses explicit path variables and simple path matching in mux. Regex is only used in a few specific routes for input validation within path variables (e.g., /{id:[0-9]+} in mux).

Missing Implementation:

One or two older routes in mux still use slightly more complex regex for path segment matching which could be refactored to use standard mux path variables.

Mitigation Strategy: Route Collision Awareness

Description:

  • Step 1: Route Definition Review: Carefully review all route definitions in your gorilla/mux router, paying attention to routes that might have overlapping or similar patterns defined in mux.
  • Step 2: Specificity Ordering: Understand mux's route matching behavior, which prioritizes more specific routes. Ensure that more specific routes are defined before more general or overlapping routes in mux if you intend for the specific routes to take precedence.
  • Step 3: Route Conflict Detection (Manual or Automated): Manually analyze route definitions in mux for potential conflicts. For larger applications, consider developing or using a tool to automatically detect potential route collisions based on patterns defined in mux.
  • Step 4: Clear Route Naming/Comments: Use clear and descriptive names or comments for route handlers and route definitions in mux. This helps in understanding the purpose of each route and identifying potential conflicts during reviews of mux routes.
  • Step 5: Testing for Route Behavior: Write integration tests that specifically test mux route matching behavior, especially in scenarios where routes might overlap. Verify that requests are routed to the intended handlers based on the defined route priorities in mux.

List of Threats Mitigated:

  • Route Hijacking/Bypass (Severity: Medium): Route collisions in mux can lead to requests being routed to unintended handlers.
  • Unexpected Behavior (Severity: Medium): Unclear route matching behavior in mux due to collisions can lead to unexpected application behavior.

Impact:

  • Route Hijacking/Bypass: Medium reduction in risk. Being aware of and preventing route collisions in mux reduces misrouting.
  • Unexpected Behavior: Medium reduction in risk. Clear mux route definitions and collision avoidance lead to more predictable behavior.

Currently Implemented:

Partially implemented. Developers are generally aware of mux route specificity, but a formal process for route collision detection and documentation for mux routes is missing.

Missing Implementation:

A documented process for route collision detection and prevention for mux routes should be established. Automated tooling for detecting potential collisions in mux route definitions could also be beneficial.

Mitigation Strategy: Path Variable Security

Description:

  • Step 1: Identify Path Variables: Review all routes defined in mux and identify path variables used in each route (e.g., /users/{userID}, /products/{productID} in mux routes).
  • Step 2: Define Expected Input Format: For each path variable in mux routes, define the expected input format and constraints (e.g., integer, UUID, alphanumeric, specific length, allowed characters).
  • Step 3: Implement Validation in Handlers: Within route handlers associated with mux routes, use mux.Vars(r) to retrieve path variables. Immediately after retrieval, implement input validation logic to check if the variable conforms to the defined expected format and constraints.
  • Step 4: Reject Invalid Input: If a path variable retrieved by mux.Vars fails validation, reject the request with an appropriate HTTP error code (e.g., 400 Bad Request).
  • Step 5: Sanitize Input (If Necessary): If sanitization is needed for path variables obtained from mux.Vars, perform sanitization after validation.

List of Threats Mitigated:

  • Path Traversal Attacks (Severity: High): Without validation, path variables from mux.Vars used to construct file paths can be manipulated.
  • Injection Attacks (e.g., SQL Injection, Command Injection) (Severity: High): Path variables from mux.Vars used in queries or commands can be exploited if not validated.
  • Application Logic Errors (Severity: Medium): Invalid path variable input from mux.Vars can lead to unexpected application behavior.

Impact:

  • Path Traversal Attacks: High reduction in risk. Validating path variables from mux.Vars used for file access is crucial.
  • Injection Attacks: High reduction in risk. Validating path variables from mux.Vars before use in queries/commands reduces injection risks.
  • Application Logic Errors: Medium reduction in risk. Input validation of mux.Vars improves application robustness.

Currently Implemented:

Partially implemented. Basic type validation for path variables from mux.Vars is done in some handlers, but comprehensive validation is not consistent.

Missing Implementation:

Need to implement consistent and comprehensive input validation for path variables obtained via mux.Vars in all relevant route handlers.

Mitigation Strategy: Handler Security in Context of mux

Description:

  • Step 1: Route-Specific Input Validation in Handlers: Implement input validation within your request handlers that are associated with specific routes defined in mux. Tailor validation to the expected parameters defined by mux for each route.
  • Step 2: Secure Parameter Handling: When retrieving parameters from the request using mux's functions (e.g., mux.Vars, mux.Query), treat these parameters as untrusted input within your handlers. Always validate and sanitize these parameters before using them in any operations within handlers associated with mux routes.

List of Threats Mitigated:

  • Injection Attacks (e.g., SQL Injection, Command Injection, Cross-Site Scripting) (Severity: High): Insecure handler logic processing parameters obtained via mux can lead to injection attacks.
  • Business Logic Errors (Severity: Medium): Handlers not properly validating parameters from mux can lead to unexpected behavior.
  • Data Integrity Issues (Severity: Medium): Handlers processing unvalidated parameters from mux can cause data corruption.

Impact:

  • Injection Attacks: High reduction in risk. Secure handlers processing mux parameters are essential for preventing injection.
  • Business Logic Errors: Medium reduction in risk. Input validation in handlers improves application robustness.
  • Data Integrity Issues: Medium reduction in risk. Validating parameters in handlers helps maintain data integrity.

Currently Implemented:

Partially implemented. Input validation exists in some handlers associated with mux routes, but consistency and comprehensiveness are lacking.

Missing Implementation:

Need to ensure all handlers associated with mux routes implement robust input validation and secure parameter handling for all parameters obtained via mux functions.