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Attack Surface Analysis for kitao/pyxel

Attack Surface: Resource Loading (Path Traversal)

  • Description: Attackers attempt to load arbitrary files from the system using Pyxel's resource loading functions.
  • How Pyxel Contributes: Pyxel's pyxel.image(), pyxel.sound(), and pyxel.tilemap() functions are the direct mechanism for loading resources. If these functions are used with unsanitized user-provided input for file paths, a path traversal attack is possible. This is a direct consequence of how Pyxel is used.
  • Example: A game allows users to specify a custom image for their character profile. An attacker provides a path like "../../../../etc/passwd" to the pyxel.image() function (indirectly, through the game's UI), attempting to read system files.
  • Impact: Disclosure of sensitive system files, potentially leading to further compromise.
  • Risk Severity: High to Critical (depending on the accessible files and the operating system).
  • Mitigation Strategies:
    • Developers:
      • Strict Whitelisting: Never load resources directly from user-provided paths. Use a hardcoded whitelist of allowed resource names and load them from a fixed, trusted directory within the application's package. This is the most important mitigation.
      • Input Sanitization (if absolutely necessary, but strongly discouraged): If user input must influence resource loading, implement extremely strict input sanitization and validation. Reject any input containing path traversal characters (.., /, \) or suspicious file extensions. This is much less secure than whitelisting. A whitelist is always preferred.
      • Resource Integrity Checks: While primarily useful for malformed files, verifying checksums before loading can add an extra layer of defense, even against path traversal (by detecting unexpected files).
    • Users:
      • Download from Trusted Sources: Only download Pyxel games from official sources (e.g., the developer's website, a reputable game distribution platform).

Attack Surface: Resource Loading (Malformed Files - Triggering Vulnerabilities in Underlying Libraries via Pyxel)

  • Description: Attackers provide malformed resource files (images, sounds, tilemaps) to trigger vulnerabilities in the underlying libraries used by Pyxel (SDL2_image, SDL2_mixer).
  • How Pyxel Contributes: Pyxel's resource loading functions (pyxel.image(), pyxel.sound(), pyxel.tilemap()) are the direct interface through which these malformed files are passed to the vulnerable libraries. Pyxel acts as the conduit for the attack.
  • Example: An attacker provides a specially crafted, corrupted .png file that exploits a known (or zero-day) vulnerability in SDL2_image. The game, using pyxel.image() to load the file, triggers the vulnerability.
  • Impact: Potential arbitrary code execution (though increasingly difficult with modern libraries and OS protections), denial of service (crash).
  • Risk Severity: High (potential for code execution, even if difficult).
  • Mitigation Strategies:
    • Developers:
      • Regular Updates: Keep Pyxel and all its dependencies (especially SDL2, SDL2_image, SDL2_mixer) up-to-date to incorporate security patches. This is crucial.
      • Fuzz Testing: Fuzz test Pyxel's resource loading functions with a wide variety of malformed and corrupted files. This helps identify vulnerabilities before they are publicly disclosed.
      • Resource Integrity Checks: Before loading a resource, verify its integrity using checksums. This helps detect tampered files, even if they aren't specifically crafted to exploit a known vulnerability.
    • Users:
      • Download from Trusted Sources: Only download Pyxel games from official sources.
      • Keep Software Updated: Keep your operating system and any relevant software (like graphics drivers) up-to-date.