attack-surface.md

Attack Surface Analysis for jonschlinkert/kind-of

Attack Surface: Type Confusion leading to Security Bypass

• Description: kind-of might misidentify the type of a JavaScript value in a way that can be predictably exploited. If application security logic relies directly and unvalidated on kind-of's output, this misclassification can lead to security bypasses. This is especially critical if the application trusts kind-of's type identification for access control or critical data handling.
• How kind-of contributes to the attack surface: By providing a type identification function, kind-of becomes a point of trust in the application's type checking process. If this trust is misplaced (i.e., kind-of is assumed to be infallible for security purposes), and kind-of makes a mistake, it directly opens a vulnerability.
• Example:
  • An application uses kind-of(userInput) to check if an input is a "string" before using it as a key to access a protected resource.
  • An attacker crafts a JavaScript object with a specific structure or overridden toString method that causes kind-of to incorrectly identify it as a "string".
  • The application, directly trusting kind-of's output without further validation, uses this object as a key, potentially bypassing intended access controls and granting access to sensitive resources that should only be accessible with a valid string key.
• Impact: Security bypass, unauthorized access to resources, potential for data manipulation or further exploitation depending on the application's logic and the context where the type confusion occurs.
• Risk Severity: High
• Mitigation Strategies:
  • Never rely solely on kind-of for security-critical type validation. Treat kind-of as a helpful utility, but always implement robust, application-specific input validation and sanitization independent of kind-of's output, especially for security-sensitive operations.
  • Assume kind-of can be incorrect. Design your security logic to be resilient to potential misclassifications by kind-of. Implement a "defense in depth" approach where type checking is only one layer of security, not the sole gatekeeper.
  • Favor explicit and stricter type checks for security contexts. Instead of relying on a general "kind-of" check, use more specific and reliable methods for validating data types in security-critical code paths. For example, use typeof checks combined with more specific validation logic relevant to the expected data format and content.
  • Thoroughly test input validation logic. Test your application's input validation with a wide range of inputs, including edge cases and potentially malicious payloads, to ensure that type confusion vulnerabilities are not exploitable, even if kind-of is used.