attack-surface.md

Attack Surface Analysis for spring-projects/spring-boot

Attack Surface: 1. Unsecured Spring Boot Actuators

• Description: Exposure of Spring Boot Actuator endpoints without proper authentication and authorization, allowing unauthorized access to sensitive application information and management functions.
• Spring Boot Contribution: Spring Boot directly provides Actuators as a core feature for monitoring and management. By default, many sensitive endpoints are enabled and accessible without authentication if security configurations are not explicitly implemented.
• Example: An attacker accesses the /actuator/shutdown endpoint without authentication and shuts down the production application, causing a denial of service.
• Impact: Denial of service, information disclosure (environment variables, configuration details), potential for unauthorized application management, and in severe cases, remote code execution (via specific actuators like Jolokia if enabled).
• Risk Severity: Critical.
• Mitigation Strategies:
  • Disable Actuators in Production: If monitoring and management via actuators are not required in production, disable them entirely using management.endpoints.enabled-by-default=false.
  • Implement Robust Authentication and Authorization: Secure Actuators using Spring Security. Enforce authentication for access and implement role-based authorization to restrict access to sensitive endpoints to authorized users/roles only.
  • Use Dedicated Management Port and Network Isolation: Expose Actuators on a separate, non-public port using management.server.port and management.server.address. Further isolate this port to a dedicated management network if possible.

Attack Surface: 2. Spring Boot DevTools Enabled in Production

• Description: Accidental or intentional deployment of Spring Boot applications with the DevTools dependency enabled in production environments, exposing highly sensitive and insecure development-time functionalities.
• Spring Boot Contribution: Spring Boot provides DevTools as a development-time convenience feature. Its presence in production is a direct consequence of including the spring-boot-devtools dependency and not properly disabling it for production builds.
• Example: DevTools is mistakenly included in a production deployment. Attackers discover the /jolokia endpoint (exposed by DevTools) and exploit it to achieve remote code execution on the server, gaining full control of the application and potentially the underlying system.
• Impact: Remote code execution, complete server compromise, data breaches, full application takeover.
• Risk Severity: Critical.
• Mitigation Strategies:
  • Strictly Disable DevTools in Production: Ensure DevTools is explicitly disabled for production builds. This is typically achieved by excluding the spring-boot-devtools dependency in production profiles or using build tool configurations to prevent its inclusion in production artifacts.
  • Profile-Specific Dependency Management: Utilize Spring Boot profiles and build tool profiles (Maven, Gradle) to manage dependencies, ensuring spring-boot-devtools is only included in development profiles and explicitly excluded in production.
  • Automated Build and Deployment Pipelines: Implement automated build and deployment pipelines that enforce profile-specific builds and prevent accidental inclusion of DevTools in production deployments.

Attack Surface: 3. Verbose Error Pages and Stack Traces in Production

• Description: Default Spring Boot error pages displaying detailed stack traces and internal application information in production environments, leaking sensitive technical details to potential attackers.
• Spring Boot Contribution: Spring Boot's default error handling configuration, especially without profile-specific overrides, tends to be verbose and developer-friendly. This default behavior, if not customized for production, directly contributes to information leakage.
• Example: An unhandled exception occurs in a production application. The default error page reveals detailed stack traces including internal class names, file paths, and potentially database connection strings, aiding attackers in understanding the application's internals and identifying potential vulnerabilities.
• Impact: Information disclosure, aiding attackers in reconnaissance and targeted attacks, potentially revealing sensitive configuration details or internal application logic.
• Risk Severity: High.
• Mitigation Strategies:
  • Customize Error Handling for Production: Implement custom error handling using @ControllerAdvice and @ExceptionHandler to provide generic, user-friendly error pages in production environments that do not expose stack traces or internal details.
  • Configure Error Page Details in Production Profiles: Explicitly configure server.error.include-stacktrace=NEVER and server.error.include-message=NEVER in application.properties or application.yml for production profiles to suppress stack traces and detailed error messages in error responses.
  • Use Production Profiles Consistently: Ensure the application is always deployed with a properly configured production profile that automatically applies hardened error handling settings.

Attack Surface: 4. Over-Exposed Spring Data REST Endpoints (Potential for Mass Assignment)

• Description: Unintentional exposure of sensitive data and potential for mass assignment vulnerabilities through automatically generated REST endpoints by Spring Data REST, especially when default configurations are used without careful consideration of data exposure and access control.
• Spring Boot Contribution: Spring Boot integrates and simplifies the use of Spring Data REST, making it easy to expose repositories as REST APIs. This ease of use can lead to developers inadvertently exposing more data than intended if default configurations are not reviewed and customized.
• Example: A Spring Data REST repository for User entities is exposed without proper projections or field-level security. Attackers send a crafted POST/PATCH request to /users/{id} with unexpected parameters, successfully modifying sensitive fields like isAdmin or passwordResetToken due to mass assignment vulnerabilities.
• Impact: Data breaches, unauthorized data modification, privilege escalation, mass assignment vulnerabilities leading to unintended changes in application state.
• Risk Severity: High.
• Mitigation Strategies:
  • Utilize Spring Data REST Projections: Define Spring Data REST projections to explicitly control which fields are exposed in REST responses, limiting data exposure to only necessary information and preventing over-exposure of sensitive attributes.
  • Implement Field-Level Security and Input Validation: Implement robust input validation and field-level security rules to prevent mass assignment vulnerabilities. Use @JsonProperty(access = Access.READ_ONLY) or similar mechanisms to control field mutability and prevent unauthorized modifications.
  • Apply Access Control and Authorization: Use Spring Security to implement authentication and authorization rules for Spring Data REST endpoints, restricting access based on user roles and permissions. Carefully define who can create, read, update, and delete entities.
  • Review and Customize Default Endpoints: Thoroughly review the automatically generated REST endpoints by Spring Data REST and customize or disable those that expose sensitive data or functionalities unnecessarily. Consider if Spring Data REST's default behavior aligns with your security requirements and API design principles.