libmagic-type-confusion

What problem does it solve?

Applications that use libmagic or the file command to validate uploaded file types block dangerous formats like HTML, SVG, and executables to prevent attacks. This Skill enables you to bypass these validation checks by exploiting libmagic's JSON nesting depth limit to cause type confusion, allowing you to test if malicious file types can reach downstream processing pipelines.

Core Features & Use Cases

• libmagic Usage Detection: Identifies if a target application uses libmagic, python-magic, finfo, or related bindings for file type validation.
• Payload Generation: Creates deeply nested JSON payloads embedded with target file signatures (e.g., PDF, HTML, SVG) that trick libmagic into misidentifying the file type.
• Use Case: Use this Skill during authorized red teaming engagements to test if your organization's file upload functionality can be exploited to smuggle executable or scriptable content past MIME checks and into trusted processing pipelines.

Quick Start

Use the libmagic-type-confusion skill to generate a deeply nested JSON payload that tricks the target's libmagic-based upload validator into misidentifying a PDF file as JSON, then upload it to the target's file upload endpoint to test if the PDF reaches the downstream processing pipeline.