Attack Surface Analysis for airbnb/mvrx

Attack Surface: Unvalidated Intent/Action Handling

Description: Intents/Actions are the primary way to change state in MvRx. Insufficient validation of Intent parameters allows attackers to directly manipulate the application's state in unintended and potentially dangerous ways.
How MvRx Contributes: MvRx's core state management mechanism relies entirely on Intents/Actions. The framework provides the structure, but does not enforce any validation; this is entirely the developer's responsibility. This is a direct and fundamental aspect of MvRx.
Example: An Intent like UpdateUserProfile(userId, newRole) without any role validation could allow a malicious user to set newRole to "admin," granting themselves full administrative privileges. Another example: an Intent to delete a resource, DeleteResource(resourceId), without checking if the user owns that resource.
Impact: Privilege escalation, data corruption, denial of service, bypassing security controls, potentially complete application compromise.
Risk Severity: Critical (if Intents are exposed externally, handle sensitive data, or control critical functionality) or High (if Intents are internal but still poorly validated, potentially leading to internal privilege escalation or data corruption).
Mitigation Strategies:
- Strict Input Validation: Implement rigorous input validation for every Intent parameter. Use strong typing (Kotlin's type system), data classes, and potentially schema validation libraries. Validate data types, ranges, lengths, and allowed values.
- Authorization Checks: Perform thorough authorization checks before processing any Intent that modifies sensitive data or performs privileged actions. Verify the user's identity and permissions within the reducer before applying the state change.
- Intent Scoping: Carefully control the visibility of Intents. Use internal Intents for sensitive operations. Avoid exposing Intents through external interfaces (deep links, broadcast receivers) unless absolutely necessary, and if you must do so, implement extremely robust validation and authorization.
- Rate Limiting: Implement rate limiting on Intent processing to prevent attackers from flooding the system with malicious Intents, which could lead to denial of service or exacerbate other vulnerabilities.

Attack Surface: Excessive State Exposure via Selectors

Description: Selectors are MvRx's mechanism for exposing parts of the application state to Views. Overly broad or poorly designed Selectors can leak sensitive information or internal implementation details, which attackers can use to their advantage.
How MvRx Contributes: MvRx uses Selectors as the sole method for Views to access the state. While MvRx encourages focused Selectors, it doesn't enforce this; it's a developer responsibility. This is a direct consequence of MvRx's design.
Example: A Selector that returns the entire user object, including the user's authentication token or session ID, instead of just the user's display name. Another example: exposing internal IDs or database keys that could be used in other attacks.
Impact: Information disclosure (potentially including sensitive data like tokens, PII, or internal identifiers), aiding in state reconstruction attacks, facilitating the discovery and exploitation of other vulnerabilities.
Risk Severity: High (if sensitive data is exposed, potentially leading to account compromise or data breaches).
Mitigation Strategies:
- Principle of Least Privilege (Data): Design Selectors to return only the absolute minimum data required by the View. Never expose entire state objects or large, complex data structures unnecessarily.
- Data Transformation and Sanitization: Use Selectors to transform and sanitize data before exposing it to the View. Redact sensitive fields (passwords, tokens, API keys), format data appropriately, and remove any unnecessary or potentially dangerous information.
- Data Transfer Objects (DTOs): Create specific data projections (DTOs) tailored for each View, containing only the necessary fields. This avoids exposing the raw state objects and provides a clear contract between the ViewModel and the View.
- Code Reviews: Conduct thorough code reviews of all Selector implementations, paying close attention to what data is being exposed and whether it's truly necessary.

Attack Surface: Race Conditions in Asynchronous Operations

Description: MvRx heavily relies on asynchronous operations for tasks like network requests and database interactions. Improper handling of concurrency within reducers can lead to race conditions, resulting in inconsistent or corrupted state.
How MvRx Contributes: While MvRx provides the Async<T> construct to help manage asynchronous operations, it's still possible to misuse it or introduce race conditions if state updates within reducers are not handled atomically. The framework provides tools, but correct usage is crucial.
Example: Two concurrent network requests attempting to update the same user profile field. If the reducer doesn't handle the responses in a thread-safe manner, one update might overwrite the other, leading to data loss or inconsistency.
Impact: Data corruption, inconsistent application state, unpredictable behavior, potential denial-of-service vulnerabilities in extreme cases.
Risk Severity: High (if race conditions affect critical data or functionality, potentially leading to data loss or security bypasses).
Mitigation Strategies:
- Correct Async<T> Usage: Utilize MvRx's Async<T> and its associated states (Uninitialized, Loading, Success, Fail) correctly to manage the lifecycle of asynchronous operations. Handle each state appropriately in your reducers.
- Atomic State Updates: Ensure that state updates within the copy() method of your state class are atomic. Avoid modifying multiple, logically related parts of the state in separate, unsynchronized operations. MvRx's immutable state and the copy() method are designed to help with this, but developers must use them correctly.
- Avoid Shared Mutable State: Minimize or eliminate the use of shared mutable state outside of the MvRx state management system. Any shared mutable state is a potential source of race conditions.
- Thorough Testing: Conduct extensive and rigorous testing of asynchronous operations under various conditions (high network latency, simulated network errors, concurrent requests) to identify and eliminate potential race conditions. Use testing frameworks that support concurrency testing.