T09 · Insecure Skill Coding Practices
- Location
scripts/video_generate.py:31- Finding
Arbitrary Local File Disclosure Through Insufficient Image Validation
- Content
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Vulnerability Details
File Location:
scripts/video_generate.py, lines 31–42 and 70–90
Vulnerability Type: Arbitrary local-file disclosure to an external API
Risk Level: MediumVulnerable Code:
python def get_image_content(image_input: str) -> str: """ Process image input. If it's a local file, convert to base64 data URI. Otherwise, assume it's a URL and return as is. """ if os.path.isfile(image_input): try: mime_type, _ = mimetypes.guess_type(image_input) if not mime_type: # Fallback or default mime_type = "image/png" with open(image_input, "rb") as image_file: encoded_string = base64.b64encode(image_file.read()).decode("utf-8") return f"data:{mime_type};base64,{encoded_string}" except Exception as e: print(f"Failed to read or encode image file {image_input}: {e}") return None return image_inputpython if first_frame_image: image_url_or_base64 = get_image_content(first_frame_image) if image_url_or_base64: content.append( {"type": "image_url", "image_url": {"url": image_url_or_base64}} ) response = client.content_generation.tasks.create( model=model_name, content=content, )Technical Analysis
The first-frame argument is documented as an image path, but the implementation only checks whether the supplied path refers to a regular file. It does not verify that the file is actually an image.
mimetypes.guess_type()infers a type from the filename rather than the file contents. If no type is recognized, the code labels the file asimage/pngregardless of its actual format. It then reads and Base64-encodes the complete file and places it in a data URI submitted to the external Ark API.Consequently, any regular file ...[truncated 1800 chars]
- Remediation
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Remediation Suggestions
- Resolve local paths to canonical paths and restrict access to an explicitly approved workspace or upload directory.
- Reject files whose detected content type is not an approved image format; do not default unknown files to
image/png. - Validate file signatures and decode the input with a trusted image library before transmission.
- Reject symbolic links where appropriate, and verify the canonical path after resolution to prevent directory-boundary bypasses.
- Apply a conservative maximum file-size limit before reading the file into memory.
- Require explicit user confirmation before uploading a local file to an external service, especially in Agent-driven execution.
- Clearly document that local first-frame image contents are transmitted to the Ark API.
- Prefer a constrained file-selection interface over accepting unrestricted filesystem paths.