Trust Assessment
substack-formatter received a trust score of 10/100, placing it in the Untrusted category. This skill has significant security findings that require attention before use in production.
SkillShield's automated analysis identified 13 findings: 6 critical, 6 high, 1 medium, and 0 low severity. Key findings include Arbitrary command execution, Dangerous call: subprocess.run(), Use of shell=True with subprocess.run for user-derived content.
The analysis covered 4 layers: Manifest Analysis, Static Code Analysis, Dependency Graph, LLM Behavioral Safety. The Manifest Analysis layer scored lowest at 0/100, indicating areas for improvement.
Last analyzed on February 13, 2026 (commit 13146e6a). SkillShield performs automated 4-layer security analysis on AI skills and MCP servers.
Layer Breakdown
Behavioral Risk Signals
Security Findings13
| Severity | Finding | Layer | Location | |
|---|---|---|---|---|
| CRITICAL | Arbitrary command execution Python shell execution (os.system, subprocess) Review all shell execution calls. Ensure commands are static (not built from user input), use absolute paths, and are strictly necessary. Prefer library APIs over shell commands. | Manifest | skills/maddiedreese/substack-formatter/copy_to_substack.py:30 | |
| CRITICAL | Arbitrary command execution Python shell execution (os.system, subprocess) Review all shell execution calls. Ensure commands are static (not built from user input), use absolute paths, and are strictly necessary. Prefer library APIs over shell commands. | Manifest | skills/maddiedreese/substack-formatter/copy_to_substack.py:53 | |
| CRITICAL | Arbitrary command execution Python shell execution (os.system, subprocess) Review all shell execution calls. Ensure commands are static (not built from user input), use absolute paths, and are strictly necessary. Prefer library APIs over shell commands. | Manifest | skills/maddiedreese/substack-formatter/copy_to_substack.py:69 | |
| CRITICAL | Arbitrary command execution Python shell execution (os.system, subprocess) Review all shell execution calls. Ensure commands are static (not built from user input), use absolute paths, and are strictly necessary. Prefer library APIs over shell commands. | Manifest | skills/maddiedreese/substack-formatter/copy_to_substack.py:73 | |
| CRITICAL | Arbitrary command execution Python shell execution (os.system, subprocess) Review all shell execution calls. Ensure commands are static (not built from user input), use absolute paths, and are strictly necessary. Prefer library APIs over shell commands. | Manifest | skills/maddiedreese/substack-formatter/copy_to_substack.py:84 | |
| CRITICAL | Arbitrary command execution Python shell execution (os.system, subprocess) Review all shell execution calls. Ensure commands are static (not built from user input), use absolute paths, and are strictly necessary. Prefer library APIs over shell commands. | Manifest | skills/maddiedreese/substack-formatter/copy_to_substack.py:105 | |
| HIGH | Dangerous call: subprocess.run() Call to 'subprocess.run()' detected in function 'check_dependencies'. This can execute arbitrary code. Avoid using dangerous functions like exec/eval/os.system. Use safer alternatives. | Static | skills/maddiedreese/substack-formatter/copy_to_substack.py:53 | |
| HIGH | Dangerous call: subprocess.run() Call to 'subprocess.run()' detected in function 'copy_with_pandoc'. This can execute arbitrary code. Avoid using dangerous functions like exec/eval/os.system. Use safer alternatives. | Static | skills/maddiedreese/substack-formatter/copy_to_substack.py:69 | |
| HIGH | Dangerous call: subprocess.run() Call to 'subprocess.run()' detected in function 'copy_with_pandoc'. This can execute arbitrary code. Avoid using dangerous functions like exec/eval/os.system. Use safer alternatives. | Static | skills/maddiedreese/substack-formatter/copy_to_substack.py:73 | |
| HIGH | Dangerous call: subprocess.run() Call to 'subprocess.run()' detected in function 'copy_with_pandoc'. This can execute arbitrary code. Avoid using dangerous functions like exec/eval/os.system. Use safer alternatives. | Static | skills/maddiedreese/substack-formatter/copy_to_substack.py:84 | |
| HIGH | Dangerous call: subprocess.run() Call to 'subprocess.run()' detected in function 'verify_clipboard'. This can execute arbitrary code. Avoid using dangerous functions like exec/eval/os.system. Use safer alternatives. | Static | skills/maddiedreese/substack-formatter/copy_to_substack.py:105 | |
| HIGH | Dangerous call: subprocess.run() Call to 'subprocess.run()' detected in function 'copy_html_to_clipboard'. This can execute arbitrary code. Avoid using dangerous functions like exec/eval/os.system. Use safer alternatives. | Static | skills/maddiedreese/substack-formatter/copy_to_substack.py:30 | |
| MEDIUM | Use of shell=True with subprocess.run for user-derived content The `copy_html_to_clipboard` function in `copy_to_substack.py` uses `subprocess.run` with `shell=True`. The command executed involves `cat`ting a temporary file (whose content is derived from user input) and piping it to `xclip`. While the temporary file path is securely generated and quoted, and the user-controlled content is piped rather than directly interpolated into the shell command, using `shell=True` introduces an additional layer of parsing by the system shell. This practice is generally discouraged as it can lead to unexpected behavior or potential vulnerabilities if the shell environment is compromised, or if subtle shell metacharacters in the piped content could be misinterpreted in unforeseen ways. A safer alternative, demonstrated by the `copy_with_pandoc` function in the same file, is to pass input directly to `subprocess.run` via the `input` argument and avoid `shell=True` entirely. Refactor the `copy_html_to_clipboard` function to avoid `shell=True`. Instead of writing to a temporary file and `cat`ing it, pass the `html_content` directly to `xclip`'s stdin using `subprocess.run(['xclip', '-selection', 'clipboard', '-t', 'text/html'], input=html_content, text=True)`. This eliminates the need for a temporary file and the use of `shell=True`. | LLM | copy_to_substack.py:25 |
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