attack-surface.md

Attack Surface Analysis for dotnet/orleans

Attack Surface: Unauthorized Grain Access

• Description: Attackers attempt to interact with grains (activate, invoke methods) they are not authorized to access.
• How Orleans Contributes: Orleans' distributed nature and ease of obtaining grain references can make it easier for attackers to attempt unauthorized access if proper controls aren't in place. Predictable grain IDs exacerbate this.
• Example: An attacker guesses a grain ID for a UserAccountGrain and attempts to call a GetBalance() method without proper authentication.
• Impact: Data breaches (sensitive information disclosure), unauthorized actions (e.g., transferring funds), system compromise.
• Risk Severity: Critical
• Mitigation Strategies:
  • Strong Authorization: Implement robust authorization checks within each grain method. Do not rely solely on the client's ability to obtain a grain reference. Use role-based access control (RBAC) or attribute-based access control (ABAC).
  • Secure Grain IDs: Avoid predictable grain IDs. Use GUIDs or cryptographically strong random identifiers, especially for sensitive grains.
  • Input Validation: Thoroughly validate all inputs to grain methods to prevent injection attacks or other malicious data.
  • Authentication: Require strong authentication for all clients interacting with the Orleans cluster.

Attack Surface: Message Interception/Modification (MITM)

• Description: Attackers intercept or modify messages exchanged between grains or between clients and silos.
• How Orleans Contributes: Orleans relies on network communication for inter-grain and client-silo interactions. Without proper security, this communication is vulnerable.
• Example: An attacker intercepts a message containing a password reset token sent between two grains.
• Impact: Data breaches, credential theft, impersonation, manipulation of application logic.
• Risk Severity: Critical
• Mitigation Strategies:
  • TLS Encryption: Enforce TLS for all inter-silo and client-to-silo communication. Orleans provides built-in support for this.
  • Message-Level Encryption: For highly sensitive data, consider encrypting the message payload in addition to TLS.
  • Message Integrity: Use digital signatures or HMACs to verify the integrity of messages and prevent tampering.

Attack Surface: Denial of Service (DoS) via Grain/Resource Exhaustion

• Description: Attackers flood the system with requests, overwhelming grains, silos, or the underlying storage provider.
• How Orleans Contributes: Orleans' scalability features, if not properly configured, can be abused to amplify DoS attacks. Unbounded grain activations or excessive timer/reminder creation can lead to resource exhaustion.
• Example: An attacker repeatedly activates a large number of short-lived grains, consuming all available memory on the silos.
• Impact: Service unavailability, performance degradation, potential system crashes.
• Risk Severity: High
• Mitigation Strategies:
  • Rate Limiting: Implement rate limiting on grain activations and method invocations. Use Orleans' built-in features or custom logic.
  • Resource Quotas: Set limits on the number of grains, timers, and reminders that can be created by a single client or user.
  • Load Shedding: Use Orleans' load shedding capabilities to gracefully handle overload situations.
  • Monitoring and Alerting: Monitor cluster health, resource utilization, and request rates. Set up alerts for unusual activity.
  • Circuit Breakers: Implement circuit breaker patterns to prevent cascading failures and isolate overloaded components.

Attack Surface: Deserialization Attacks

• Description: Attackers exploit vulnerabilities in the deserialization process to inject malicious code.
• How Orleans Contributes: Orleans uses serialization to transmit data between grains and to persist grain state. If the serialization format is vulnerable, attackers can exploit this.
• Example: An attacker sends a crafted message containing a malicious object that, when deserialized, executes arbitrary code on the silo.
• Impact: Remote code execution (RCE), system compromise.
• Risk Severity: Critical
• Mitigation Strategies:
  • Secure Serializers: Use a secure serialization format that supports type whitelisting or other security mechanisms. Avoid binary serializers known to be vulnerable.
  • Type Whitelisting: If using a serializer that supports it, configure a whitelist of allowed types to prevent deserialization of arbitrary objects.
  • Input Validation (Pre-Deserialization): Validate data before deserialization to the extent possible. This can help prevent some attacks.
  • Custom Serializers: Consider using Orleans' custom serializer support to implement additional security checks during serialization and deserialization.

Attack Surface: Compromised Silo

• Description: An attacker gains control of a single silo within the Orleans cluster.
• How Orleans Contributes: Orleans operates as a distributed system. A compromised silo can potentially impact the entire cluster.
• Example: An attacker exploits an operating system vulnerability on a silo host to gain root access.
• Impact: Data breaches, system compromise, denial of service, potential propagation to other silos.
• Risk Severity: Critical
• Mitigation Strategies:
  • Host Security: Implement strong host-level security for all silo instances (firewalls, intrusion detection, regular patching).
  • Network Segmentation: Isolate silos from other parts of the infrastructure using network segmentation.
  • Least Privilege: Run silos with the least privilege necessary. Avoid running as root or administrator.
  • Monitoring and Auditing: Monitor silo activity for suspicious behavior. Implement security auditing.
  • Secure Membership Provider: Use a secure membership provider with strong authentication and authorization to prevent unauthorized silos from joining the cluster.

Attack Surface: Insecure Stream Access

• Description: Unauthorized access to Orleans Streams, allowing attackers to read, write, or tamper with stream data.
• How Orleans Contributes: Orleans Streams provide a mechanism for asynchronous communication. If not properly secured, streams can be a vector for attack.
• Example: An attacker subscribes to a stream containing sensitive financial transactions without authorization.
• Impact: Data breaches, data manipulation, disruption of application logic.
• Risk Severity: High
• Mitigation Strategies:
  • Authentication and Authorization: Implement authentication and authorization for stream access (subscription and publishing).
  • TLS Encryption: Use TLS to encrypt stream communication.
  • Message-Level Security: Consider message-level encryption and signing for sensitive stream data.
  • Stream Provider Security: Follow security best practices for the chosen stream provider (e.g., Azure Event Hubs, Kafka).