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attack-surface.md

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Attack Surface Analysis for rwf2/rocket

Attack Surface: Route Parsing and Matching (ReDoS)

  • Description: Exploitation of Rocket's route parsing to cause a Denial of Service (DoS) via computationally expensive regular expression matching.
  • Rocket's Contribution: Rocket's routing mechanism, while generally robust, may use regular expressions internally (even if abstracted). If these are not carefully crafted or limited, a ReDoS attack is possible.
  • Example: An attacker sends a request with a crafted URL designed to trigger worst-case performance in a poorly written regular expression used for route matching (e.g., a URL containing many repeating characters followed by a non-matching character).
  • Impact: Denial of Service (DoS). The application becomes unresponsive.
  • Risk Severity: High.
  • Mitigation Strategies:
    • Developer:
      • Avoid overly complex regular expressions in route definitions. If regex is unavoidable, use tools to analyze them for ReDoS vulnerabilities (e.g., regex101.com with a timeout, or specialized ReDoS checkers).
      • Implement strict input validation before route matching occurs, limiting the characters and length allowed in URL segments. This limits the attacker's control over the input to the regex engine.
      • Fuzz test the routing system with a wide range of valid and invalid URLs, specifically targeting potential ReDoS patterns.
    • User/Administrator:
      • Deploy a Web Application Firewall (WAF) with rules specifically designed to detect and block ReDoS patterns. Many WAFs have pre-built rules for this.

Attack Surface: Request Data Handling (Oversized Payloads)

  • Description: Attacks leveraging Rocket's request data handling to cause a Denial of Service (DoS) by sending excessively large request bodies.
  • Rocket's Contribution: Rocket provides mechanisms for handling various data formats (forms, JSON, etc.). While it should have default limits, these might be insufficient or misconfigured. Custom FromData implementations are a particular concern.
  • Example: An attacker sends a POST request with a multi-gigabyte JSON payload, causing the server to exhaust memory and crash.
  • Impact: Denial of Service (DoS). The application becomes unavailable.
  • Risk Severity: High.
  • Mitigation Strategies:
    • Developer:
      • Use Rocket's built-in data validation features (Form, Json, Valid) to enforce strict size limits on all incoming data. Explicitly set reasonable maximum sizes.
      • Thoroughly audit and test any custom FromData implementations to ensure they handle large inputs safely and have appropriate size limits.
      • Fuzz test data handling endpoints with a range of payload sizes, including very large ones.
    • User/Administrator:
      • Configure server-level limits on request body sizes (e.g., in a reverse proxy like Nginx or Apache). This provides a defense-in-depth layer, even if Rocket's limits are bypassed.

Attack Surface: Fairing Misconfiguration (Bypass)

  • Description: Exploitation of incorrectly ordered or vulnerable Rocket fairings to bypass security controls.
  • Rocket's Contribution: Fairings are a core Rocket feature, providing extensibility. Incorrect ordering can render security fairings ineffective.
  • Example: An authentication fairing is placed after a fairing that handles sensitive data or a routing fairing that exposes an unprotected endpoint, allowing an attacker to access the data or endpoint without authentication.
  • Impact: Bypass of security controls (authentication, authorization), leading to unauthorized access to data or functionality.
  • Risk Severity: High.
  • Mitigation Strategies:
    • Developer:
      • Carefully review and document the order of all fairings. Ensure that security-critical fairings (authentication, authorization, input validation) are executed before any fairings that handle sensitive data or perform routing to potentially vulnerable endpoints. Use a clear, consistent naming convention for fairings to aid in understanding their purpose and order.
      • Thoroughly audit and test all custom fairing implementations, paying close attention to their interaction with other fairings.
    • User/Administrator:
      • Regularly review application configuration and code to verify the correct ordering of fairings.

Attack Surface: Server-Side Template Injection (SSTI) - If Templating is Used

  • Description: Injection of malicious template code into server-side templates, leading to arbitrary code execution.
  • Rocket's Contribution: While Rocket doesn't enforce a specific templating engine, it's commonly used with them. The vulnerability is highly dependent on the chosen engine and how it's used in conjunction with Rocket. Rocket's role is in how it passes data to the templating engine.
  • Example: An attacker provides input like {{ 7 * 7 }} (or a more complex, engine-specific payload) to a field that is rendered directly into a template without proper sanitization or escaping. The server executes the code.
  • Impact: Arbitrary code execution on the server (extremely serious), data breaches, complete system compromise.
  • Risk Severity: Critical.
  • Mitigation Strategies:
    • Developer:
      • Choose a templating engine with automatic output escaping. This is the primary defense. Examples include Tera (with autoescaping enabled) and newer versions of many popular engines.
      • Strictly validate and sanitize all user-supplied data before passing it to the template engine. Never trust user input, even if it appears to be safe.
      • Avoid concatenating strings to build templates. Use the templating engine's built-in features for variable substitution and control flow. This reduces the risk of accidental injection.
      • Regularly update the templating engine to the latest version to patch any known vulnerabilities.
    • User/Administrator:
      • Use a Web Application Firewall (WAF) to detect and block common SSTI payloads. Many WAFs have rulesets specifically for this.