threat-modeling.md

Threat Model Analysis for comfyanonymous/comfyui

Threat: Malicious Workflow Deserialization

• Description: An attacker crafts a malicious ComfyUI workflow file (JSON) with embedded code. When a user loads this workflow in ComfyUI, the malicious payload is executed during deserialization, leading to arbitrary code execution on the ComfyUI server.
• Impact:
  • Critical: Full compromise of the ComfyUI server, including data breaches, system takeover, and denial of service.
• Affected Component:
  • ComfyUI workflow loading and deserialization functionality.
• Risk Severity: Critical
• Mitigation Strategies:
  • Strictly validate workflow JSON structure and content during deserialization.
  • Run workflow deserialization in a sandboxed environment.
  • Implement code review for workflow deserialization logic.
  • Advise users to load workflows only from trusted sources.

Threat: Node Parameter Injection

• Description: An attacker injects malicious code into parameters of ComfyUI nodes. If ComfyUI node implementations lack input sanitization, this injected code can be executed by the server, leading to command injection or other code execution vulnerabilities.
• Impact:
  • High: Arbitrary code execution on the ComfyUI server, potentially leading to data breaches, system compromise, or denial of service.
• Affected Component:
  • ComfyUI node parameter handling in core and custom nodes.
• Risk Severity: High
• Mitigation Strategies:
  • Implement robust input sanitization and validation for all node parameters in ComfyUI.
  • Apply the principle of least privilege to node operations.
  • Promote secure coding practices for ComfyUI node development.
  • Conduct regular security audits of ComfyUI nodes.

Threat: Malicious Model Loading

• Description: An attacker provides a malicious model file to ComfyUI. This model contains embedded malicious code that executes when ComfyUI loads or uses the model. Users might be tricked into loading these models from untrusted sources within ComfyUI.
• Impact:
  • High: Code execution on the ComfyUI server, potentially leading to data breaches, system compromise, or denial of service.
• Affected Component:
  • ComfyUI model loading functionality and model loading libraries.
• Risk Severity: High
• Mitigation Strategies:
  • Verify the source and integrity of models loaded into ComfyUI.
  • Scan model files for malware before loading.
  • Load models in a sandboxed environment.
  • Keep ComfyUI and model loading libraries updated.

Threat: Custom Node Vulnerabilities

• Description: Custom nodes for ComfyUI, often from third parties, may contain vulnerabilities (coding errors, insecure dependencies, malicious code). Installing vulnerable custom nodes can directly compromise the ComfyUI instance.
• Impact:
  • High to Critical: Data breaches, system compromise, or denial of service, depending on the custom node vulnerability.
• Affected Component:
  • ComfyUI custom node loading mechanism and individual custom node implementations.
• Risk Severity: High to Critical
• Mitigation Strategies:
  • Review custom node code before installation, especially from untrusted sources.
  • Check custom node dependencies for vulnerabilities.
  • Install only necessary custom nodes from trusted developers.
  • Utilize community feedback to identify potentially risky custom nodes.
  • Consider sandboxing custom node execution.

Threat: Python Code Execution through Nodes

• Description: Vulnerabilities in ComfyUI node implementations or the core framework can allow attackers to execute arbitrary Python code on the server by exploiting insecure node logic or input handling within ComfyUI workflows.
• Impact:
  • Critical: Full compromise of the ComfyUI server, including data breaches, system takeover, and denial of service.
• Affected Component:
  • ComfyUI node implementations, core framework, and Python execution environment within ComfyUI.
• Risk Severity: Critical
• Mitigation Strategies:
  • Employ secure coding practices in ComfyUI node and framework development.
  • Implement rigorous input validation and sanitization for all node inputs.
  • Run ComfyUI components with the principle of least privilege.
  • Conduct regular security audits and penetration testing of ComfyUI.

Threat: Dependency Vulnerabilities

• Description: ComfyUI relies on Python libraries. Vulnerabilities in these dependencies can be exploited through ComfyUI if they are not updated. Attackers can leverage known vulnerabilities in outdated libraries used by ComfyUI to compromise the system.
• Impact:
  • High to Critical: Data breaches, system compromise, or denial of service, depending on the dependency vulnerability.
• Affected Component:
  • Python dependencies used by ComfyUI.
• Risk Severity: High to Critical
• Mitigation Strategies:
  • Regularly scan ComfyUI dependencies for vulnerabilities.
  • Keep all Python dependencies updated with security patches.
  • Use virtual environments to isolate ComfyUI dependencies.
  • Implement Software Composition Analysis (SCA) for continuous dependency monitoring.

Threat: Insecure File System Operations

• Description: Insecure file handling in ComfyUI, such as insufficient path sanitization, can lead to arbitrary file read/write or directory traversal vulnerabilities. Attackers can exploit these to access sensitive files or overwrite system files through ComfyUI.
• Impact:
  • High: Unauthorized file access, data breaches, potential system compromise.
• Affected Component:
  • ComfyUI file system operation functions.
• Risk Severity: High
• Mitigation Strategies:
  • Strictly sanitize and validate all file paths used in ComfyUI file operations.
  • Limit file system access privileges of the ComfyUI process.
  • Implement file system Access Control Lists (ACLs).
  • Use secure file handling libraries in ComfyUI development.

Threat: Lack of Built-in Authentication/Authorization (Default Setup)

• Description: By default, ComfyUI often runs without authentication. Anyone with network access can control the application. This default lack of security in ComfyUI allows unauthorized users to execute workflows and access data.
• Impact:
  • High: Unauthorized access to ComfyUI, potential data breaches, unauthorized resource use, and malicious system manipulation.
• Affected Component:
  • ComfyUI's web server and default access control configuration.
• Risk Severity: High (if exposed to untrusted networks)
• Mitigation Strategies:
  • Implement authentication in ComfyUI (e.g., username/password, OAuth).
  • Implement authorization to control user actions within ComfyUI.
  • Restrict network access to ComfyUI using firewalls if authentication is not implemented.
  • Use a reverse proxy with authentication in front of ComfyUI.