T09 · Insecure Skill Coding Practices
Warning
- Location
scripts/gen.py:123- Finding
Stored HTML Injection in the Generated Image Gallery
- Content
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None: thumbs = "\n".join( [ f"""{it["prompt"]} """.strip() for it in items ] ) html = f""" openai-image-gen :root {{ color-scheme: dark; }} body {{ margin: 24px; font: 14px/1.4 ui-sans-serif, system-ui; background: #0b0f14; color: #e8edf2; }} h1 {{ font-size: 18px; margin: 0 0 16px; }} .grid {{ display: grid; grid-template-columns: repeat(auto-fill, minmax(240px, 1fr)); gap: 16px; }} figure {{ margin: 0; padding: 12px; border: 1px solid #1e2a36; border-radius: 14px; background: #0f1620; }} img {{ width: 100%; height: auto; border-radius: 10px; display: block; }} figcaption {{ margin-top: 10px; color: #b7c2cc; }} code {{ color: #9cd1ff; }}
openai-image-gen
Output:
{out_dir.as_posix()}{thumbs}""" ``` ### Technical Analysis The gallery generator constructs HTML through direct string interpolation. The prompt supplied through `--prompt` is stored in each item and inserted verbatim into the `` element. The user-controlled output-directory path is likewise inserted into a `` element without HTML escaping. Consequently, HTML metacharacters in either value are interpreted as markup rather than displayed as text. For example, a prompt containing: ```html``` would create an executable event handler in the generated `index.html`. This is a stored HTML injection vulnerability because the malicious value is persisted in ...[truncated 2082 chars]
- Remediation
View remediation
None: thumbs = "\n".join( f"""{html.escape(it["prompt"], quote=True)} """.strip() for it in items ) escaped_out_dir = html.escape(out_dir.as_posix(), quote=True) ``` 2. Insert `escaped_out_dir` instead of the raw path: ```python
Output:
``` 3. Prefer a maintained template engine with automatic HTML escaping if gallery generation becomes more complex. 4. Continue constraining generated filenames to a safe character set. Explicitly allowlist output formats such as `png`, `jpeg`, and `webp` before using them as filename extensions. 5. Add regression tests that generate galleries from prompts and paths containing characters such as `<`, `>`, `"`, `'`, and `&`. Verify that these appear as encoded text and cannot create elements or event handlers. 6. Consider adding a restrictive Content Security Policy to the generated gallery as defense in depth: ```html ``` HTML escaping remains mandatory because a Content Security Policy alone does not prevent all markup injection or deceptive-content attacks. ]]>{escaped_out_dir}