threat-modeling.md

Threat Model Analysis for go-kit/kit

Threat: Endpoint Hijacking via Malicious Middleware

• Description: An attacker crafts or compromises a custom middleware component specifically designed to interact with go-kit's transport layer. This malicious middleware intercepts incoming requests before they reach the intended go-kit endpoint handler. The attacker leverages the middleware's position within the go-kit request processing pipeline to modify the request, steal credentials passed through go-kit mechanisms, redirect the request, or inject code that executes within the application's context, taking advantage of go-kit's request handling flow.
• Impact: Complete compromise of the application. The attacker gains full control over the affected endpoint, potentially leading to data breaches, unauthorized actions, and system compromise. This is critical because it bypasses all subsequent go-kit layers.
• Affected Kit Component: transport layer (specifically, custom middleware implementations that hook into go-kit's transport mechanisms), endpoint layer (as the intended go-kit endpoint is bypassed).
• Risk Severity: Critical
• Mitigation Strategies:
  • Strict Code Review: Mandatory, thorough code reviews for all custom middleware, with a focus on security implications, specifically examining how the middleware interacts with go-kit's request/response lifecycle.
  • Dependency Management: Use Go modules to track and update all middleware dependencies. Regularly check for security advisories related to used middleware, paying close attention to any that integrate with go-kit.
  • Least Privilege: Middleware should only have the minimum necessary permissions.
  • Input Validation: Implement robust input validation before any go-kit middleware processing.
  • Use Well-Vetted Middleware: Prefer community-maintained, well-tested middleware known to be compatible with go-kit over custom implementations.

Threat: Context Manipulation for Impersonation

• Description: An attacker exploits a vulnerability in a go-kit middleware, endpoint, or service to modify the context.Context object that is passed between go-kit components. They inject values that impersonate another user or role, bypassing authentication or authorization checks that rely on context data as managed by go-kit. This leverages the central role of context.Context in go-kit's design.
• Impact: Unauthorized access to resources and functionality. The attacker performs actions they are not permitted to, potentially leading to data breaches or unauthorized modifications. This is high severity because it abuses a core go-kit mechanism.
• Affected Kit Component: endpoint layer, service layer, any go-kit middleware that modifies the context.Context. The context.Context, as used within the go-kit framework, is the primary vector.
• Risk Severity: High
• Mitigation Strategies:
  • Context Validation: Treat go-kit context values as potentially untrusted. Validate any security-critical data extracted from the go-kit context within the service layer.
  • Strong Typing: Use strongly-typed structures within the go-kit context for security-related data.
  • Independent Authorization: Implement authorization checks within the service layer, independent of go-kit context values set by earlier components. Do not rely solely on the go-kit context for security.
  • Unexported Context Keys: Use unexported context keys as recommended by go-kit to prevent accidental or malicious overwriting.
  • Avoid Sensitive Data in Context: Minimize sensitive data stored directly in the go-kit context.

Threat: Request/Response Tampering via Middleware

• Description: Similar to endpoint hijacking, but a malicious go-kit middleware modifies the request or response body, headers, or other parameters as they are processed by go-kit's transport layer. This could lead to data corruption, injection of malicious data, or bypassing security controls that rely on the integrity of the request/response as handled by go-kit.
• Impact: Data integrity violations, potential for code injection, unauthorized actions, and information disclosure. This is high severity due to the potential for widespread impact through a single compromised middleware.
• Affected Kit Component: transport layer (specifically, custom middleware implementations interacting with go-kit's transport mechanisms).
• Risk Severity: High
• Mitigation Strategies:
  • (Same as Endpoint Hijacking - focus on go-kit middleware security)
  • Checksums/Signatures: For critical data, consider checksums or digital signatures to verify integrity between go-kit layers.
  • Logging of Modifications: Log any modifications made by go-kit middleware to requests or responses.

Threat: Sensitive Data Exposure in Logs

• Description: The application logs sensitive data due to careless logging practices within go-kit components (middleware, endpoints, or the service layer), potentially using go-kit's logging facilities incorrectly. This includes logging raw requests/responses, context values, or error details that contain sensitive information.
• Impact: Information disclosure, leading to potential account compromise, data breaches, and privacy violations. High severity due to the potential for widespread and persistent exposure.
• Affected Kit Component: Any component that uses logging, particularly if using go-kit's logging integrations or patterns (middleware, endpoint, service, transport).
• Risk Severity: High
• Mitigation Strategies:
  • Log Review: Thoroughly review all logging statements within go-kit components to ensure they do not include sensitive information.
  • Data Redaction: Use a logging library that supports redaction or masking, especially if integrating with go-kit's logging.
  • Data Sanitization: Sanitize data before logging, paying attention to data handled by go-kit.
  • Structured Logging: Use structured logging (e.g., JSON) as recommended by go-kit for easier filtering.
  • Log Level Management: Use appropriate log levels to minimize sensitive data exposure in production.

Threat: Authorization Bypass via Context Manipulation

• Description: An attacker exploits a vulnerability to modify the go-kit context.Context and inject values that bypass authorization checks that are implemented using go-kit's context propagation. This is a specific type of elevation of privilege, directly targeting go-kit's core mechanism.
• Impact: Unauthorized access to protected resources, leading to data breaches or unauthorized modifications. High severity because it undermines go-kit's intended use.
• Affected Kit Component: endpoint layer, service layer, any go-kit middleware that modifies or relies on the context.Context for authorization.
• Risk Severity: High
• Mitigation Strategies:
  • (Same as "Context Manipulation for Impersonation" - focus on independent authorization checks within the service layer, not solely relying on go-kit's context)
  • RBAC/ABAC: Implement a robust authorization model (RBAC or ABAC) and enforce it consistently, independent of the go-kit context.