threat-modeling.md

Threat Model Analysis for ruby-concurrency/concurrent-ruby

Threat: Race Condition Exploitation

Description: Attackers exploit race conditions arising from concurrent access to shared mutable state managed by concurrent-ruby primitives (e.g., Atomic, Mutex). By carefully timing requests, they can manipulate data inconsistently, bypassing security checks or corrupting critical information.

Impact: Data corruption, unauthorized access, privilege escalation, financial loss, denial of service.

Affected Component: Concurrent::Atom, Concurrent::Mutex, Concurrent::ReentrantReadWriteLock, Concurrent::Hash, Concurrent::Array, Futures, Promises, Actors.

Risk Severity: High to Critical.

Mitigation Strategies:

• Utilize concurrent-ruby synchronization primitives correctly to protect shared mutable state.
• Favor immutable data structures to minimize the need for synchronization.
• Thoroughly test concurrent code for race conditions using appropriate tools and techniques.
• Conduct security code reviews focusing on concurrency and data sharing patterns.

Threat: Deadlock-Induced Denial of Service

Description: Attackers trigger deadlocks by crafting requests that cause threads managed by concurrent-ruby (e.g., in thread pools, actors) to block each other indefinitely while waiting for resources (locks, etc.). This leads to application unresponsiveness and denial of service.

Impact: Denial of service, application unresponsiveness, resource exhaustion.

Affected Component: Concurrent::Mutex, Concurrent::ReentrantReadWriteLock, Futures, Promises, Actors, Thread Pools.

Risk Severity: High.

Mitigation Strategies:

• Implement timeouts for lock acquisition when using concurrent-ruby mutexes.
• Design concurrent workflows to minimize lock contention and complex locking patterns.
• Monitor application threads and resource usage to detect potential deadlocks.
• Consider actor-based concurrency to reduce reliance on explicit locks.

Threat: Thread Pool Exhaustion Attack

Description: Attackers flood the application with requests, overwhelming concurrent-ruby thread pools (ThreadPoolExecutor, FixedThreadPool, etc.). This exhausts available threads, preventing legitimate tasks from being processed and causing denial of service.

Impact: Denial of service, application unresponsiveness, performance degradation.

Affected Component: Concurrent::ThreadPoolExecutor, Concurrent::FixedThreadPool, Concurrent::CachedThreadPool.

Risk Severity: High.

Mitigation Strategies:

• Use bounded concurrent-ruby thread pools with appropriate maximum sizes.
• Implement request rate limiting and throttling mechanisms.
• Employ queue management and backpressure to handle request surges effectively.
• Monitor thread pool utilization and adjust pool sizes dynamically if needed.

Threat: Memory Leak Exploitation via Concurrent Objects

Description: Attackers trigger memory leaks by exploiting improper object lifecycle management in concurrent contexts created by concurrent-ruby (Futures, Promises, Actors). Unreleased references in closures or callbacks within concurrent tasks can lead to gradual memory exhaustion and application failure.

Impact: Denial of service (application crash due to out-of-memory errors), performance degradation.

Affected Component: Futures, Promises, Actors, Closures used within concurrent tasks.

Risk Severity: High.

Mitigation Strategies:

• Carefully manage object lifecycles within concurrent-ruby concurrency constructs.
• Use weak references where appropriate to prevent unintended object retention in concurrent contexts.
• Implement proper resource cleanup within concurrent tasks and callbacks.
• Regularly monitor application memory usage and profile for leaks, especially in concurrent code paths.

Threat: Unhandled Exception Propagation leading to Inconsistent State

Description: Attackers trigger exceptions within concurrent tasks managed by concurrent-ruby (Futures, Actors, Thread Pools). If these exceptions are not properly handled using concurrent-ruby's error handling mechanisms (e.g., .rescue on Futures), it can lead to inconsistent application state, data corruption, or silent failures.

Impact: Data corruption, inconsistent application state, denial of service, logging failures, unexpected application behavior.

Affected Component: Futures, Promises, Actors, Thread Pools, Concurrent::Promise.rescue, Concurrent::Future.rescue.

Risk Severity: High.

Mitigation Strategies:

• Implement robust error handling within all concurrent tasks using concurrent-ruby's error handling features.
• Utilize .rescue and .then with error callbacks for Futures and Promises to catch and handle exceptions.
• Implement centralized logging and monitoring for exceptions occurring in concurrent tasks.
• Design error handling strategies to maintain data consistency and application stability even during concurrent failures.

Threat: Exploitation of concurrent-ruby Library Vulnerabilities

Description: Attackers exploit known or zero-day vulnerabilities present in the concurrent-ruby library code itself. This could involve crafting specific inputs or actions that trigger vulnerabilities, potentially leading to remote code execution, denial of service, or information disclosure.

Impact: Critical - Remote code execution, denial of service, information disclosure, complete system compromise.

Affected Component: The entire concurrent-ruby library.

Risk Severity: Critical.

Mitigation Strategies:

• Keep the concurrent-ruby library updated to the latest stable version to patch known vulnerabilities.
• Monitor security advisories and vulnerability databases related to concurrent-ruby and its dependencies.
• Implement a robust vulnerability management process for all third-party libraries, including concurrent-ruby.
• Conduct regular security assessments and penetration testing to identify potential vulnerabilities.