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Security audit

YouTube Video Downloader

Security checks across malware telemetry and agentic risk

Overview

The skill does what it claims, but it sends user-supplied URLs and an API key to a third-party service and requires unbounded verbatim output from that service.

Review before installing. Use this only with YouTube links you are authorized to download, understand that the URL and RedFox API key are sent to redfox.hk, avoid saving the key unless needed, and treat returned descriptions or links as untrusted external content.

SkillSpector

By NVIDIA
Vulnerability Patterns
  • Data ExfiltrationExternal Transmission, Env Variable Harvesting, File System Enumeration
  • Output HandlingUnvalidated Output Injection, Cross-Context Output, Unbounded Output
  • System Prompt LeakageDirect Leakage, Indirect Extraction, Tool-Based Exfiltration
  • Trigger AbuseOverly Broad Trigger, Shadow Command Trigger, Keyword Baiting Trigger
  • Prompt InjectionInstruction Override, Hidden Instructions, Exfiltration Commands
Findings (8)

Vague Triggers

Medium
Confidence
87% confidence
Finding
The skill is advertised as triggerable via broad natural-language requests such as 'Download this video' or 'Help me save this Short' rather than a narrowly scoped command. This increases the chance of unintended activation or misuse in adjacent conversations, especially because the capability facilitates downloading third-party content with legal and policy sensitivity.

Missing User Warnings

Medium
Confidence
95% confidence
Finding
The README promotes downloading, backing up, and remixing YouTube content without any warning about copyright, platform terms, or authorization requirements. In this context, the omission materially increases the risk that users will use the skill for infringing or non-compliant content acquisition, making the skill more dangerous than a generic file downloader.

Missing User Warnings

Medium
Confidence
92% confidence
Finding
The script transmits both a user-supplied YouTube URL and the API key to the third-party service redfox.hk, but it does not provide a meaningful privacy or trust warning before doing so. In a skill context, this can surprise users and may expose sensitive viewing targets, internal URLs accidentally pasted by a user, or credentials to an external operator without informed consent.

Unbounded Output

Medium
Category
Output Handling
Content
### Core Features

- **Video Parsing**: paste a YouTube video link to parse out watermark-free video download URLs (returned resources may include video and audio files in various formats).
- **Complete Information**: displays resource type, duration, download link, and cover link for every resolution; full description shown line by line without truncation.
- **Multi-Format Support**: recognizes regular videos, Shorts, and short links (youtu.be).

---
Confidence
71% confidence
Finding
without truncation

Unbounded Output

Medium
Category
Output Handling
Content
- **Output**: Returns the video download URL directly — copy it into your browser or download tool to save
- **Link Display Rule**: Download and cover links must be displayed in full; never use `...` or any form of truncation
- **Field Display Rule**: The returned result must fully display the following fields:
  - Description (desc): full text displayed line by line, no truncation
  - Resource list: for each resource object, display its type, duration (durationSeconds), download link (downloadUrl), and cover link (coverUrl)
  - When the API does not return a resources array, automatically fall back to extracting top-level fields with the same names for compatibility
Confidence
88% confidence
Finding
no truncation

Unbounded Output

Medium
Category
Output Handling
Content
print(f"\n{GREEN}{BOLD}✓ Parsed successfully!{RESET}")

    # Full description (original text, no truncation)
    if desc:
        print(f"\n{CYAN}{BOLD}📝 Description:{RESET}")
        for line in str(desc).splitlines():
Confidence
78% confidence
Finding
no truncation

Direct Prompt Extraction

High
Category
System Prompt Leakage
Content
- **Content Type**: Video/Audio (MP4 / WebM / M4A and other formats; resources may include video and audio files)
- **Input**: Paste a YouTube video link (one link per request; batch upload not supported)
- **Output**: Returns the video download URL directly — copy it into your browser or download tool to save
- **Link Display Rule**: Download and cover links must be displayed in full; never use `...` or any form of truncation
- **Field Display Rule**: The returned result must fully display the following fields:
  - Description (desc): full text displayed line by line, no truncation
  - Resource list: for each resource object, display its type, duration (durationSeconds), download link (downloadUrl), and cover link (coverUrl)
Confidence
84% confidence
Finding
Display Rule

Direct Prompt Extraction

High
Category
System Prompt Leakage
Content
- **Input**: Paste a YouTube video link (one link per request; batch upload not supported)
- **Output**: Returns the video download URL directly — copy it into your browser or download tool to save
- **Link Display Rule**: Download and cover links must be displayed in full; never use `...` or any form of truncation
- **Field Display Rule**: The returned result must fully display the following fields:
  - Description (desc): full text displayed line by line, no truncation
  - Resource list: for each resource object, display its type, duration (durationSeconds), download link (downloadUrl), and cover link (coverUrl)
  - When the API does not return a resources array, automatically fall back to extracting top-level fields with the same names for compatibility
Confidence
84% confidence
Finding
Display Rule

VirusTotal

65/65 vendors flagged this skill as clean.

View on VirusTotal

Static analysis

No suspicious patterns detected.