attack-surface.md

Attack Surface Analysis for arrow-kt/arrow

Attack Surface: 1. Unhandled Errors (Ignoring Either/Result)

• Description: Failure to properly handle the error branch of Either, Result, or Validated constructs, leading to unexpected program behavior.
• How Arrow Contributes: Arrow provides these constructs for explicit error handling, but developers can choose to ignore the error case. This is the core risk of using Arrow's error handling.
• Example:

  val result: Either<Error, User> = getUserFromDatabase(userId)
  val user = result.getOrNull() // Ignoring the potential Left(Error)
  // ... use user, potentially causing a NullPointerException or worse

• Impact: Data corruption, information leakage (through unhandled exceptions reaching the user), denial of service (due to resource exhaustion), logic flaws bypassing security checks.
• Risk Severity: High (Can lead to a variety of serious issues, depending on the context).
• Mitigation Strategies:
  • Mandatory Code Reviews: Enforce code reviews that specifically check for proper handling of Either/Result/Validated. Reject code that ignores the error branch without explicit justification.
  • Static Analysis (Custom Rules): Develop or find static analysis tools/lint rules that flag unhandled Either/Result values. Standard Kotlin null-safety checks are insufficient.
  • Comprehensive Error Testing: Write unit and integration tests that specifically trigger error conditions and verify that the application handles them gracefully and securely. Focus on boundary conditions and invalid inputs.
  • Error Handling Training: Provide developers with training on Arrow's error handling best practices, emphasizing the importance of handling all possible outcomes.

Attack Surface: 2. Uncontrolled Side Effects (Outside IO)

• Description: Performing side effects (e.g., database writes, network calls, file I/O) outside of Arrow's IO monad, leading to concurrency problems and unpredictable behavior.
• How Arrow Contributes: Arrow's IO is designed to manage side effects, but developers might bypass it or misuse it. This is a direct misuse of a core Arrow feature.
• Example:

  fun updateUser(user: User) {
      // Side effect OUTSIDE of IO:
      database.update(user) // Direct database interaction, potential race condition
      sendEmailNotification(user) // Another side effect outside IO
  }

  A correct example would be:

  fun updateUser(user: User): IO<Unit> = IO {
      database.update(user)
      sendEmailNotification(user)
  }

• Impact: Data races, deadlocks, resource leaks, inconsistent application state, potential for denial-of-service attacks.
• Risk Severity: High (Concurrency issues are notoriously difficult to debug and can have severe consequences).
• Mitigation Strategies:
  • Strict IO Enforcement: Establish a coding standard that requires all side effects to be encapsulated within IO. Code reviews should enforce this strictly.
  • Concurrency Testing: Implement robust concurrency testing using tools that can detect race conditions and deadlocks. This is crucial for identifying subtle concurrency bugs.
  • Resource Management with Resource: Utilize Arrow's Resource type to ensure that resources (e.g., database connections, file handles) are acquired and released safely, even in the presence of errors or exceptions.
  • Minimize Shared Mutable State: Favor immutable data structures and functional programming principles to reduce the risk of concurrency issues. Avoid shared mutable state whenever possible.

Attack Surface: 3. Vulnerable Transitive Dependencies

• Description: Vulnerabilities in libraries that Arrow-kt depends on (transitively), which can be exploited to compromise the application.
• How Arrow Contributes: Arrow, like any library, has dependencies, and those dependencies might have their own dependencies. This is an indirect, but important, aspect of using any library, including Arrow.
• Example: If Arrow depends on a version of a logging library with a known remote code execution vulnerability, the application using Arrow is also vulnerable.
• Impact: Remote code execution (RCE), denial of service (DoS), data breaches, a wide range of potential security compromises.
• Risk Severity: Critical (Vulnerabilities in dependencies can be just as dangerous as vulnerabilities in the application's own code).
• Mitigation Strategies:
  • Software Composition Analysis (SCA): Use SCA tools (e.g., OWASP Dependency-Check, Snyk, Dependabot) to automatically scan your project's dependencies for known vulnerabilities. Integrate this into your CI/CD pipeline.
  • Regular Dependency Updates: Establish a policy of regularly updating Arrow-kt and all of its transitive dependencies to the latest stable versions. Automate this process as much as possible.
  • Dependency Minimization: Be mindful of the number of dependencies you introduce. Avoid unnecessary dependencies to reduce the overall attack surface.
  • Vulnerability Monitoring: Subscribe to security advisories and mailing lists related to Arrow-kt and its dependencies to stay informed about newly discovered vulnerabilities.