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Mitigation Strategies Analysis for graphite-project/graphite-web

Mitigation Strategy: Strict URL Parameter Validation and Whitelisting

  • Mitigation Strategy: Strict URL Parameter Validation and Whitelisting

    • Description:

      1. Identify All Endpoints: List every URL endpoint exposed by Graphite-web (e.g., /render, /metrics/find, /dashboard/load).
      2. Define Allowed Parameters: For each endpoint, create a whitelist specifying:
        • Allowed parameter names (e.g., target, from, until, format).
        • Expected data type for each parameter (integer, string, timestamp, specific enum).
        • Maximum length for string parameters.
        • Allowed character set (e.g., alphanumeric, specific punctuation).
        • Regular expressions (used sparingly and with extreme caution) to define allowed patterns if absolutely necessary. Prefer simpler validation methods.
      3. Implement Validation Logic: In the Graphite-web code handling each endpoint (likely in Django views or middleware):
        • Before processing any request, check if the incoming URL contains only the whitelisted parameters.
        • For each parameter, validate its value against the defined type, length, and character set restrictions.
        • Reject the request (with a 400 Bad Request) if any parameter is invalid or unexpected.
        • Log the rejection, including the source IP, the invalid parameter, and the reason.
      4. Use a Validation Library: Employ a robust validation library within the Graphite-web code (e.g., cerberus, jsonschema, or Django's form validation).
      5. Centralize Validation: Centralize the validation logic in Graphite-web's middleware or a decorator.

    • Threats Mitigated:

      • Remote Code Execution (RCE) - Critical: Prevents attackers from injecting malicious code through crafted URL parameters. Many past Graphite-web CVEs involved RCE via parameter injection.
      • Cross-Site Scripting (XSS) - High: Limits allowed characters and validates input, reducing XSS risk.
      • Denial of Service (DoS) - Medium: Validating parameter lengths and types prevents excessively large/complex requests.
      • Information Disclosure - Medium: Prevents probing with unexpected parameters.
      • SQL Injection (if applicable) - High: Helps prevent SQL injection if parameters are used in queries.

    • Impact:

      • RCE: Risk reduction: Very High.
      • XSS: Risk reduction: High.
      • DoS: Risk reduction: Medium.
      • Information Disclosure: Risk reduction: Medium.
      • SQL Injection: Risk reduction: High (if applicable).

    • Currently Implemented: Hypothetical Example: Partially implemented in render/views.py using basic regular expressions, but not consistently applied. Uses Django's int() for some parameters, but lacks comprehensive whitelisting.

    • Missing Implementation: Hypothetical Example:

      • Missing comprehensive whitelists for all endpoints, especially /dashboard/* and /metrics/*.
      • Lacks centralized validation; validation is scattered.
      • Doesn't use a dedicated validation library; relies on ad-hoc regex and basic type conversions.
      • Insufficient logging of validation failures.

Mitigation Strategy: Content-Type Header Enforcement (Within Graphite-web)

  • Mitigation Strategy: Content-Type Header Enforcement (Within Graphite-web)

    • Description:

      1. Identify Expected Content Types: For each Graphite-web endpoint, determine the expected Content-Type (e.g., application/json, text/plain).
      2. Implement Enforcement: In the Graphite-web code (middleware or view):
        • Check the Content-Type header of incoming requests.
        • Reject the request (e.g., 415 Unsupported Media Type) if the header is missing or doesn't match.
        • Do not infer the content type from the request body.
      3. Centralize Enforcement: Implement this check in Graphite-web's middleware.

    • Threats Mitigated:

      • Content Sniffing Attacks - Medium: Prevents browsers from misinterpreting content type.
      • Unexpected Input Handling - Medium: Ensures only expected data formats are processed.

    • Impact:

      • Content Sniffing: Risk reduction: Medium.
      • Unexpected Input: Risk reduction: Medium.

    • Currently Implemented: Hypothetical Example: Implemented for JSON API endpoints in api/middleware.py, but not for all.

    • Missing Implementation: Hypothetical Example:

      • Missing enforcement for endpoints serving images or other non-JSON content.
      • Not consistently applied across all middleware.

Mitigation Strategy: Output Encoding (HTML, within Graphite-web)

  • Mitigation Strategy: Output Encoding (HTML, within Graphite-web)

    • Description:

      1. Identify HTML Output: Find all parts of Graphite-web's code that generate HTML:
        • Templates for dashboards/pages.
        • Error messages including user-supplied data.
        • Dynamically generated HTML.
      2. Implement HTML Encoding:
        • Use Django's template auto-escaping (verify it's enabled).
        • For HTML generated outside templates (in view functions), use django.utils.html.escape to encode all user-supplied data.
        • Review JavaScript code; use safe methods like textContent instead of innerHTML.
      3. Context-aware encoding: Use context-aware encoding.

    • Threats Mitigated:

      • Cross-Site Scripting (XSS) - High: Prevents injection of malicious JavaScript.

    • Impact:

      • XSS: Risk reduction: High.

    • Currently Implemented: Hypothetical Example: Django's auto-escaping is enabled, but manual HTML generation might not be encoded.

    • Missing Implementation: Hypothetical Example:

      • Audit view functions and error handling for proper HTML encoding.
      • Review JavaScript for DOM-based XSS.

Mitigation Strategy: Disable Unnecessary Features (Configuration-Based)

  • Mitigation Strategy: Disable Unnecessary Features (Configuration-Based)

    • Description:

      1. Review Configuration: Examine Graphite-web's configuration files (e.g., local_settings.py, graphite.wsgi) for settings enabling optional features.
      2. Identify Unused Features: Determine which optional features are not needed.
      3. Disable Features: Modify the configuration files to disable unused features (e.g., setting variables to False, commenting out sections).
      4. Test Thoroughly: Test the application to ensure remaining functionality works and no side effects were introduced.
      5. Document Disabled Features: Record which features were disabled and why.

    • Threats Mitigated:

      • Exploitation of Vulnerabilities in Unused Features - Variable Severity: Reduces the attack surface.
      • Unintended Functionality Exposure - Medium: Prevents access to unintended features.

    • Impact:

      • Vulnerability Exploitation: Risk reduction: Variable.
      • Unintended Functionality: Risk reduction: Medium.

    • Currently Implemented: Hypothetical Example: Some features might be disabled, but a comprehensive review hasn't been done.

    • Missing Implementation: Hypothetical Example:

      • Thorough review of all configuration options.
      • Document disabled features.
      • Re-test after disabling.