threat-modeling.md

Threat Model Analysis for lostisland/faraday

Threat: Threat: Request Spoofing via Custom Middleware

• Description: A vulnerability in the application's custom Faraday middleware allows an attacker to manipulate the outgoing HTTP request. This is not about a third-party library, but code the application developers wrote. The attacker might inject headers, modify the request body, or change the URL to impersonate a legitimate user or system, bypassing authentication or authorization checks on the external service Faraday is connecting to.
• Impact: Unauthorized access to the external service, potentially leading to data breaches, data modification, or execution of unauthorized actions on the external service. The attacker gains privileges they shouldn't have on the target of the Faraday request.
• Faraday Component Affected: Custom Faraday Middleware (specifically, the call method and how it manipulates the env[:request] object).
• Risk Severity: High
• Mitigation Strategies:
  • Strict Input Validation: Within the middleware, rigorously validate any data that influences the request (headers, body, URL parameters). Use whitelists, not blacklists.
  • Secure Header Handling: Be extremely cautious when modifying or adding HTTP headers, especially security-related headers like Authorization, Cookie, or custom headers.
  • Code Review & SAST: Mandatory code reviews focusing on the middleware's security. Use Static Application Security Testing (SAST) tools to automatically scan for vulnerabilities.
  • Principle of Least Privilege: The middleware should only have the absolute minimum permissions needed to modify the request.

Threat: Threat: Request Tampering via Third-Party Middleware

• Description: The application uses a vulnerable or malicious third-party Faraday middleware. This is a supply chain risk. The attacker exploits a known vulnerability in the middleware, or the middleware itself is intentionally designed to tamper with requests. The middleware modifies the outgoing HTTP request (headers, body, URL) to the attacker's advantage.
• Impact: Data corruption on the external service, unauthorized actions performed on the external service, bypassing security controls of the external service. The attacker can potentially inject malicious data into the request.
• Faraday Component Affected: Third-party Faraday Middleware (the call method is the critical point).
• Risk Severity: High
• Mitigation Strategies:
  • Vetting and Selection: Only use well-known, actively maintained, and reputable Faraday middleware from trusted sources. Avoid obscure or unmaintained libraries.
  • Dependency Vulnerability Scanning: Use tools like Bundler Audit or Snyk to automatically and continuously scan for known vulnerabilities in all dependencies, including Faraday middleware.
  • Immediate Patching: Apply security updates to middleware immediately upon release. Automate this process if possible.
  • Least Privilege (Middleware Choice): Choose middleware that does the minimum necessary. Avoid overly complex middleware with unnecessary features.

Threat: Threat: Response Tampering via Custom Middleware

• Description: A vulnerability in custom Faraday middleware allows modification of the response received from the external service before the main application logic processes it. The attacker might alter the response body, headers, or status code. This is distinct from general response handling vulnerabilities; it's specifically about malicious actions within the Faraday middleware.
• Impact: The application receives and processes manipulated data, potentially leading to incorrect behavior. While XSS and RCE are possible, they are primarily application-level vulnerabilities resulting from the tampered response, not direct Faraday threats. The core impact here is that Faraday delivers incorrect data to the application.
• Faraday Component Affected: Custom Faraday Middleware. The call method and specifically the handling of the env[:response] object within the middleware.
• Risk Severity: High
• Mitigation Strategies: * Code Review: Thoroughly review the middleware code, paying close attention to how the response is processed and modified. Focus on any modifications to env[:response]. * Response Validation (Within Middleware): While the application should also validate responses, the middleware should perform initial checks to ensure the response hasn't been tampered with in unexpected ways before passing it on. This might involve checking for expected headers or basic data structure integrity. * Minimize Modifications: The middleware should modify the response as little as possible. Avoid unnecessary transformations or manipulations. * SAST Tools: Use static analysis tools to identify potential vulnerabilities in the middleware's response handling.

Threat: Threat: Unintentional Proxy Exposure

• Description: Faraday is configured to use a proxy server, and this configuration is either incorrect, insecure, or inadvertently exposed. This could be due to misconfigured environment variables (http_proxy, https_proxy), hardcoded proxy settings, or a vulnerability that allows an attacker to inject proxy settings. The attacker can then intercept and potentially modify the traffic between the application and the external service.
• Impact: Man-in-the-middle attack, allowing the attacker to eavesdrop on sensitive data (API keys, credentials, request/response data) and potentially modify the traffic.
• Faraday Component Affected: Faraday::Connection options related to proxy configuration (specifically the proxy option and how it's set, including via environment variables).
• Risk Severity: High
• Mitigation Strategies:
  • Secure Configuration Management: Never hardcode proxy settings, especially credentials. Use a secure configuration management system (e.g., environment variables managed securely, a secrets management service).
  • Environment Variable Protection: If using environment variables, ensure they are set securely and are not accessible to unauthorized users or processes.
  • Proxy Authentication: If the proxy requires authentication, use strong, unique credentials and store them securely.
  • Code Review: Review any code that configures Faraday's proxy settings to ensure they are not exposed or vulnerable to injection.
  • Network Segmentation: If possible, place the application and proxy server in a separate, protected network segment.