attack-surface.md

Attack Surface Analysis for dotnet/eshop

Attack Surface: Inter-Service Communication (Unauthenticated/Unauthorized)

• Description: The risk of unauthorized access to internal microservices due to insufficient authentication or authorization between services.
• eShop Contribution: The application's microservice architecture inherently relies on inter-service communication, increasing the potential for misconfiguration or bypass of security controls. This is a core architectural choice of eShop.
• Example: An attacker discovers the internal endpoint for Ordering.API and directly sends requests to create orders, bypassing the WebMVC frontend and payment processing.
• Impact: Unauthorized data access/modification, order creation without payment, potential denial-of-service.
• Risk Severity: Critical
• Mitigation Strategies:
  • Implement Mutual TLS (mTLS): Require each service to present a valid certificate to other services, ensuring both authentication and encryption.
  • Use API Keys/Service Tokens: Assign unique, secret keys or tokens to each service for authentication. Rotate these keys regularly.
  • Implement JWT Authorization: Use JWTs with fine-grained authorization claims (scopes) to control which services can access specific resources and actions within other services. Enforce these claims at each service.
  • Network Segmentation: Use network policies (e.g., Kubernetes Network Policies) to restrict communication between services to only what is explicitly required.

Attack Surface: Event Bus (Unauthorized Message Consumption/Injection)

• Description: The risk of attackers gaining unauthorized access to the message bus (RabbitMQ or Azure Service Bus) to read sensitive messages or inject malicious ones.
• eShop Contribution: The application specifically chooses to use an event-driven architecture, relying on a message bus for asynchronous communication between services. This is a fundamental design decision.
• Example: An attacker subscribes to the OrderCreatedIntegrationEvent queue and steals order information, or injects a fake OrderPaymentFailedIntegrationEvent to disrupt order fulfillment.
• Impact: Data breach (order details, customer information), disruption of business processes (order fulfillment), potential for fraudulent activities.
• Risk Severity: High
• Mitigation Strategies:
  • Secure Message Bus Access: Implement strong authentication and authorization for access to the message bus (e.g., using usernames/passwords, certificates, or managed identities).
  • Message Encryption: Encrypt the contents of sensitive messages before publishing them to the bus.
  • Message Signing: Digitally sign messages to ensure their integrity and prevent tampering.
  • Implement Idempotency: Design services to handle duplicate messages gracefully, preventing replay attacks. Use unique message IDs and track processed messages.
  • Input Validation on Message Handlers: Rigorously validate the content of all messages received from the bus before processing them.

Attack Surface: API Gateway (Authentication/Authorization Bypass)

• Description: The risk of attackers bypassing the authentication and authorization mechanisms implemented at the API gateway (Ocelot).
• eShop Contribution: eShop specifically uses Ocelot as its API gateway, making Ocelot's security configuration and vulnerability status directly relevant to the application's attack surface.
• Example: A vulnerability in Ocelot's JWT validation allows an attacker to forge a valid JWT and access protected resources in backend services.
• Impact: Unauthorized access to all backend services and data, potential for complete system compromise.
• Risk Severity: Critical
• Mitigation Strategies:
  • Keep Ocelot Updated: Regularly update Ocelot to the latest version to patch any known security vulnerabilities.
  • Thoroughly Test Authentication/Authorization: Conduct extensive penetration testing to identify and address any weaknesses in Ocelot's authentication and authorization logic.
  • Use Strong JWT Validation: Ensure Ocelot rigorously validates all aspects of JWTs (signature, expiration, audience, issuer). Use a strong, securely stored secret key for signing JWTs.
  • Implement Rate Limiting: Configure rate limiting in Ocelot to protect against brute-force and denial-of-service attacks.
  • Least Privilege for Ocelot: Ensure that the Ocelot service itself runs with the least necessary privileges.

Attack Surface: Data Storage (SQL Injection)

• Description: The risk of attackers injecting malicious SQL code into database queries, even with the use of an ORM like EF Core.
• eShop Contribution: While EF Core helps, eShop's specific database interactions and any custom SQL queries (even within EF Core) are the direct source of potential SQL injection vulnerabilities. The choice of SQL Server and the schema design are also eShop-specific.
• Example: A custom reporting feature within eShop uses raw SQL queries with user-supplied input without proper parameterization, allowing an attacker to execute arbitrary SQL commands.
• Impact: Data breach (read, modify, or delete data), potential for complete database server compromise.
• Risk Severity: High
• Mitigation Strategies:
  • Parameterized Queries: Always use parameterized queries or prepared statements when interacting with the database, even when using EF Core. Avoid dynamic SQL construction with user input.
  • Input Validation: Strictly validate and sanitize all user input before using it in any database query, even if it's used within EF Core.
  • Least Privilege Database Users: Ensure that each application component connects to the database with a user account that has only the necessary permissions (e.g., read-only access for components that only need to read data).
  • Web Application Firewall (WAF): Use a WAF to detect and block SQL injection attempts.

Attack Surface: Identity and Access Management (Weak Authentication)

• Description: The risk of attackers compromising user accounts due to weak password policies or vulnerabilities in the IdentityServer implementation.
• eShop Contribution: eShop specifically uses and configures IdentityServer for authentication and authorization. The configuration choices made within IdentityServer directly impact the application's security.
• Example: The IdentityServer configuration within eShop allows weak passwords, and an attacker uses a dictionary attack to guess a user's password.
• Impact: Unauthorized access to user accounts, potential for data breaches and fraudulent activities.
• Risk Severity: High
• Mitigation Strategies:
  • Enforce Strong Password Policies: Require strong passwords (minimum length, complexity requirements, etc.).
  • Implement Multi-Factor Authentication (MFA): Require users to provide a second factor of authentication (e.g., a one-time code from an authenticator app) in addition to their password.
  • Protect Against Brute-Force Attacks: Implement account lockout policies and CAPTCHAs to prevent automated password guessing attacks.
  • Regularly Update IdentityServer: Keep IdentityServer updated to the latest version to patch any known security vulnerabilities.
  • Prevent Account Enumeration: Configure IdentityServer to return generic error messages for login and password reset failures, preventing attackers from determining if a username or email address exists.

Attack Surface: gRPC Services (Lack of Input Validation)

• Description: Insufficient validation of data received by gRPC services, leading to potential vulnerabilities.
• eShop Contribution: The application specifically chooses to use gRPC for some inter-service communication. The implementation of these gRPC services within eShop is the direct source of this risk.
• Example: A gRPC service within eShop accepts an integer without bounds checking, leading to a buffer overflow.
• Impact: Denial of service, potential code execution, data corruption.
• Risk Severity: High
• Mitigation Strategies:
  • Rigorous Input Validation: Implement strict input validation for all data received by gRPC services, checking data types, lengths, and ranges.
  • Use Protobuf Validation: Leverage Protobuf's built-in validation features (if available) or use a validation library.
  • Secure gRPC Communication: Always use TLS with gRPC to encrypt communication.
  • Authentication and Authorization: Implement authentication and authorization for gRPC services, similar to other services.