Skip to content

Latest commit

 

History

History
51 lines (42 loc) · 6.42 KB

threat-modeling.md

File metadata and controls

51 lines (42 loc) · 6.42 KB

Threat Model Analysis for 3b1b/manim

Threat: Uncontrolled Resource Consumption via Scene.render()

  • Description: An attacker provides a Manim script that defines an extremely long or complex animation within the Scene.render() method. This could involve a large number of Mobject instances, complex transformations, or computationally intensive operations within custom Animation subclasses. The attacker might use nested loops or recursive calls within the construct() method to amplify the complexity.
    • Impact: Denial of Service (DoS) due to server resource exhaustion (CPU, memory, disk space if temporary files are excessively large). The server may become unresponsive, affecting other users.
    • Manim Component Affected: manim.Scene.render(), manim.Mobject, manim.Animation, and potentially any custom subclasses of these. The construct() method of the Scene class is the primary entry point.
    • Risk Severity: Critical
    • Mitigation Strategies:
      • Input Validation (AST Analysis): Use Python's ast module to parse the user-provided Manim code before execution. Analyze the Abstract Syntax Tree (AST) to:
        • Limit the nesting depth of loops and function calls within construct().
        • Restrict the number of Mobject instances created (e.g., by counting calls to add()).
        • Disallow or limit the use of known resource-intensive functions or classes.
      • Resource Limits (cgroups/Docker): Enforce strict resource limits (CPU time, memory, disk I/O) using containerization technologies like Docker and cgroups.
      • Timeouts: Implement a hard timeout for the Scene.render() process. If rendering exceeds the timeout, terminate the process.
      • Frame Rate and Duration Limits: Enforce maximum frame rate and total animation duration limits.

Threat: File System Access via Text and LaTeX

  • Description: An attacker leverages the Text class, which uses LaTeX internally, to attempt to read or write arbitrary files on the server. The attacker might craft a malicious LaTeX document that uses commands like \input or \write18 (if enabled) to access sensitive files or execute shell commands. Even without \write18, clever LaTeX tricks can sometimes be used for information disclosure (e.g., probing for file existence). This is a direct threat because Manim's Text class is the gateway to this vulnerability.
    • Impact: Information Disclosure (reading sensitive files), potential Code Execution (if \write18 or similar is exploitable), or Denial of Service (overwriting critical files).
    • Manim Component Affected: manim.mobject.text.text_mobject.Text, which relies on LaTeX rendering (specifically, the tex_to_svg_file function and the underlying LaTeX engine).
    • Risk Severity: High
    • Mitigation Strategies:
      • LaTeX Sanitization: Use a LaTeX sanitizer to remove or escape potentially dangerous LaTeX commands and macros. This is crucial. Consider using a whitelist approach, allowing only a very limited set of LaTeX commands.
      • Restricted LaTeX Environment: Configure the LaTeX environment to disable features like \write18 and restrict file access. Use a chroot jail or containerization to limit LaTeX's access to the file system.
      • Input Validation (Text Content): Validate the text content provided to the Text class to prevent the injection of malicious LaTeX code. This is a defense-in-depth measure, as LaTeX sanitization should be the primary defense.
      • Separate LaTeX Process: Run the LaTeX rendering process in a separate, isolated process with minimal privileges.

Threat: Arbitrary File Write via Scene.save_state() and related methods

  • Description: If the application allows users to influence the file paths used by Scene.save_state(), Scene.save_final_image(), or similar methods, an attacker could attempt to write files to arbitrary locations on the server. This might be used to overwrite critical system files or create malicious files.
    • Impact: Denial of Service (overwriting critical files), potential Code Execution (if the attacker can overwrite executable files or configuration files), or Data Tampering.
    • Manim Component Affected: manim.Scene.save_state(), manim.Scene.save_final_image(), and any other methods that write files to disk.
    • Risk Severity: High
    • Mitigation Strategies:
      • Strict File Path Control: Never allow users to directly specify file paths. Use a predefined, secure directory for storing output files, and generate unique filenames internally (e.g., using UUIDs).
      • File System Permissions: Ensure that the Manim process has write access only to the designated output directory and no other locations.
      • Input Validation (Indirect Control): Even if users don't directly control file paths, validate any input that indirectly influences them (e.g., scene names that might be used to construct file paths).

Threat: Infinite Loop in Custom Updater

  • Description: An attacker defines a custom Updater function (using add_updater) that contains an infinite loop or a very long-running computation. This updater is then attached to a Mobject.
    • Impact: Denial of Service (DoS) due to CPU exhaustion. The rendering process will hang indefinitely.
    • Manim Component Affected: manim.Mobject.add_updater(), manim.Mobject.update(), and any custom updater functions.
    • Risk Severity: High
    • Mitigation Strategies:
      • Input Validation (AST Analysis): Analyze the AST of custom updater functions to detect potential infinite loops or long-running computations. This is challenging but can be partially addressed by limiting loop nesting and function call depth.
      • Timeouts (per Updater): Implement a timeout mechanism specifically for updater functions. If an updater takes too long to execute, terminate it. This requires careful management of the Manim event loop.
      • Whitelisting: If possible, only allow a predefined set of safe updater functions.