attack-surface.md

Attack Surface Analysis for reactivex/rxdart

Attack Surface: Stream Logic Errors

• Description: Incorrect use of RxDart operators (e.g., switchMap, debounce, combineLatest, merge, etc.) leads to unexpected application behavior, potentially bypassing security controls or causing data corruption.
  • RxDart Contribution: RxDart's rich operator set increases complexity, making it easier to introduce subtle logic errors that affect stream processing. The asynchronous nature of these operations makes debugging more difficult.
  • Example: A combineLatest operator is used to combine a stream of user roles with a stream of resource access permissions. If the roles stream emits an update before the permissions stream has completed initialization, the combined stream might temporarily grant incorrect access.
  • Impact: Bypass of security controls (e.g., rate limiting, input validation, authorization checks), data corruption, unexpected state transitions, denial of service.
  • Risk Severity: High to Critical (depending on the specific logic error and its consequences).
  • Mitigation Strategies:
    • Thorough Testing: Extensive unit and integration tests covering all stream operators and their combinations, including edge cases, error conditions, and timing-related scenarios. Focus on testing the intended behavior and unintended consequences of operator misuse.
    • Code Reviews: Focused code reviews specifically examining the use of RxDart operators and their interactions. Reviewers should have a strong understanding of RxDart's semantics.
    • Linting: Utilize linters with RxDart-specific rules (if available) to catch common operator misuse and potential logic errors.
    • Simplified Logic: Prefer simpler stream logic where possible. Break down complex streams into smaller, more manageable, and independently testable units.
    • Formal Verification (Advanced): In highly critical systems (e.g., financial applications, medical devices), consider formal verification techniques to mathematically prove the correctness of stream logic.

Attack Surface: Error Handling Failures

• Description: Unhandled errors within RxDart streams can propagate unexpectedly, leading to application crashes, inconsistent state, or bypass of security checks.
  • RxDart Contribution: RxDart's error handling model requires explicit handling of errors within streams using onError callbacks or operators like catchError. Errors can be easily overlooked or mishandled, especially in complex stream pipelines.
  • Example: A stream processing user input encounters an invalid data format error during a critical authentication step. If the error is not caught and handled, the application might skip subsequent validation steps, potentially allowing an attacker to bypass authentication.
  • Impact: Application crashes (DoS), inconsistent application state, bypass of security checks (authentication, authorization), data corruption.
  • Risk Severity: High to Critical (depending on the nature of the error and its consequences).
  • Mitigation Strategies:
    • Comprehensive Error Handling: Implement robust error handling using onError callbacks or operators like catchError and retry at every stage of the stream pipeline where errors might occur.
    • Graceful Recovery: Ensure that error handling logic leads to a graceful recovery of the application to a safe and consistent state. Avoid leaving the application in an undefined or partially updated state.
    • Logging: Log all errors appropriately, including context information (e.g., user ID, input data, timestamp) to aid in debugging and auditing.
    • Global Error Handler: Consider using a global error handler to catch any unhandled stream errors and prevent application crashes. This acts as a last line of defense.
    • Defensive Programming: Anticipate potential errors and implement defensive programming techniques (e.g., input validation, boundary checks) to prevent them from occurring in the first place.

Attack Surface: Subject State Exposure

• Description: Sensitive data stored in BehaviorSubject or ReplaySubject instances can be exposed to unauthorized components or users if access is not properly controlled.
  • RxDart Contribution: BehaviorSubject and ReplaySubject hold and replay values to all new subscribers, making them potential points of data leakage if not managed carefully. This is a fundamental characteristic of these subject types.
  • Example: A BehaviorSubject storing a user's session token. If a new, unauthorized component subscribes to this subject (perhaps due to a coding error or a dependency injection misconfiguration), it could gain access to the token and impersonate the user.
  • Impact: Unauthorized access to sensitive data (e.g., authentication tokens, personal information, financial data), potential for privilege escalation or impersonation, data breaches.
  • Risk Severity: High to Critical (depending on the sensitivity of the data).
  • Mitigation Strategies:
    • Access Control: Carefully control the scope and access to BehaviorSubject and ReplaySubject instances. Use private fields and restrict access to authorized components using dependency injection or other access control mechanisms.
    • Data Minimization: Avoid storing sensitive data directly in subjects if possible. Instead, use derived streams or other mechanisms to provide only the necessary information to subscribers, transforming or filtering the sensitive data as needed.
    • Encryption: Encrypt sensitive data stored within subjects to protect it from unauthorized access even if the subject is exposed. Use appropriate key management practices.
    • Value Clearing: Clear the subject's value (e.g., set to null or a default value) when the sensitive data is no longer needed or when the user logs out. This minimizes the window of exposure.
    • Short-Lived Subjects: Use short-lived subjects for sensitive data, disposing of them as soon as they are no longer required. This reduces the attack surface.

Attack Surface: Vulnerabilities in RxDart and its Dependencies

• Description: Vulnerabilities may exist in the RxDart library itself or its dependencies.
  • RxDart Contribution: RxDart is a third-party library, and like any software, it may contain vulnerabilities.
  • Example: A hypothetical vulnerability in RxDart's combineLatest operator that could lead to unexpected behavior under certain conditions.
  • Impact: Varies depending on the vulnerability; could range from minor issues to critical security exploits.
  • Risk Severity: Varies (Low to Critical, depending on the vulnerability). Can be High to Critical.
  • Mitigation Strategies:
    • Keep Updated: Regularly update RxDart and all its dependencies to the latest versions to receive security patches.
    • Vulnerability Scanning: Use vulnerability scanning tools to identify known vulnerabilities in RxDart and its dependencies.
    • Security Advisories: Monitor security advisories and vulnerability databases (e.g., CVE) for any reported issues related to RxDart.
    • Dependency Auditing: Regularly audit project dependencies to identify and address any outdated or vulnerable packages.