attack-tree.md

Attack Tree Analysis for kitao/pyxel

Objective: Achieve Arbitrary Code Execution on the user's machine running a Pyxel application.

Attack Tree Visualization

[Root: Achieve Arbitrary Code Execution] |

| | [Exploit Pyxel Resource Loading] [HR] [Exploit Pyxel Input Handling] |

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| | | | [1. Malicious .pyxres] [CN][HR] [2. Path Traversal] [CN][HR] [4. Unvalidated Input] | | | | | |----[4a. Command Injection] [CN] | | | |----[2a. Load arbitrary .py file] [CN][HR] | |----[2b. Access system files] | |----[1a. Inject malicious code into .pyxres] [CN][HR] |----[1b. Craft .pyxres to trigger vulnerabilities in Pyxel's parsing] [HR]

Attack Tree Path: 1. Exploit Pyxel Resource Loading [HR]

• Description: This attack vector focuses on manipulating the loading of Pyxel's custom resource file format (.pyxres). Since .pyxres files are essential for most Pyxel games, vulnerabilities in this area are highly impactful.

• 1a. Malicious .pyxres [CN][HR] - Inject malicious code into .pyxres:

  • Description: The attacker crafts a .pyxres file that contains malicious code. If the Pyxel engine's .pyxres parser has vulnerabilities (e.g., insufficient bounds checking, improper handling of data types), this code could be executed when the file is loaded.
  • Likelihood: Medium (Depends on parser robustness)
  • Impact: Very High (Arbitrary code execution)
  • Effort: Medium to High
  • Skill Level: Advanced to Expert
  • Detection Difficulty: Medium to Hard

• 1b. Malicious .pyxres [HR] - Craft .pyxres to trigger vulnerabilities in Pyxel's parsing:

  • Description: Instead of directly injecting code, the attacker crafts a malformed .pyxres file designed to trigger a vulnerability in the parser (e.g., a buffer overflow, integer overflow, or other memory corruption). This could lead to a crash or, potentially, a controlled exploit.
  • Likelihood: Medium (Depends on parser robustness)
  • Impact: High to Very High
  • Effort: Medium to High
  • Skill Level: Advanced
  • Detection Difficulty: Medium

Attack Tree Path: 2. Exploit Pyxel Input Handling

• 2. Path Traversal [CN][HR] * Description: This attack vector exploits vulnerabilities in how Pyxel handles file paths, particularly when loading resources. If the application doesn't properly sanitize file paths provided (directly or indirectly) by the user or derived from external sources, an attacker can use ".." sequences to access files outside the intended game directory.

*   **2a. Load arbitrary .py file [CN][HR]:**
    *   **Description:** The attacker uses path traversal to force Pyxel to load and execute a Python file (`.py`) from an arbitrary location on the file system. This is a direct path to arbitrary code execution.
    *   **Likelihood:** Low to Medium (High if path sanitization is missing)
    *   **Impact:** Very High (Arbitrary code execution)
    *   **Effort:** Low
    *   **Skill Level:** Novice to Intermediate
    *   **Detection Difficulty:** Easy to Medium

*   **2b. Access system files:**
    *   **Description:**  The attacker uses path traversal to read sensitive system files. While this doesn't directly lead to code execution, it can leak information that aids in further attacks.
    *   **Likelihood:** Low to Medium (High if path sanitization is missing)
    *   **Impact:** Medium to High
    *   **Effort:** Low
    *   **Skill Level:** Novice to Intermediate
    *   **Detection Difficulty:** Easy to Medium

Attack Tree Path: 3. Exploit Pyxel Input Handling

• 4. Unvalidated Input
  • 4a. Command Injection [CN]:
    • Description: This attack occurs if the Pyxel application uses user input (even indirectly) in system calls (e.g., os.system(), subprocess.Popen()) without proper sanitization. The attacker injects shell commands into the input, which are then executed by the operating system.
    • Likelihood: Very Low (Unlikely in a typical Pyxel game, but critical if present)
    • Impact: Very High (Arbitrary code execution with system privileges)
    • Effort: Low
    • Skill Level: Intermediate
    • Detection Difficulty: Easy to Medium