Getting it into your agent
One page per mod, every tool's command on it. A separate URL per tool would split the same page into five that compete with each other.
npx skills add RedHatProductSecurity/prodsec-skills --skill file-handling-uploadsgit clone --depth 1 https://github.com/RedHatProductSecurity/prodsec-skillsWrote this? Show the measurements
A badge with what this costs and how it scanned, read live from this page, so it follows the numbers instead of freezing them. Markdown for a README, HTML for a documentation site or a project page.
[](https://agentmods.dev/skills/redhatproductsecurity/prodsec-skills/file-handling-uploads)<a href="https://agentmods.dev/skills/redhatproductsecurity/prodsec-skills/file-handling-uploads"><img src="https://agentmods.dev/badge/skills/redhatproductsecurity/prodsec-skills/file-handling-uploads/github.svg" alt="Measured on agentmods" height="20"></a>Or the 80×15 button, for a site that already has a row of RSS and ATOM ones. Only the verdict fits; the numbers stay here.
<a href="https://agentmods.dev/skills/redhatproductsecurity/prodsec-skills/file-handling-uploads"><img src="https://agentmods.dev/badge/skills/redhatproductsecurity/prodsec-skills/file-handling-uploads.svg" alt="Reviewed on agentmods" width="80" height="20"></a>What it costs to keep this loaded
Counted locally with the o200k_base tokenizer, which is exact for GPT models; Claude uses its own tokenizer and its counts differ. Treat this as one consistent yardstick across the catalogue rather than a bill. Prices are per million input tokens.
| Model | Per session | Once invoked |
|---|---|---|
| Fable 5.1 | $0.00045 | $0.00783 |
| Opus 5 | $0.00023 | $0.00392 |
| Sonnet 5 | $0.00009 | $0.00157 |
| Haiku 4.5 | $0.00005 | $0.00078 |
Grade A, and why
file-handling-uploads scanned grade A with 0 findings against 26 rules in 11 categories — prompt injection, anti-refusal, data exfiltration, privilege escalation, supply chain, agent snooping, system-prompt leakage, SSRF and excessive agency — measured 11d ago.
A static scan of the body, not an audit. Every finding is printed with the line that produced it so you can judge whether it matters here. A mod is markdown that instructs an agent; that is exactly why what it instructs is worth reading.
Nothing flagged
None of the 26 patterns this scan looks for appear in this file: no shell pipes, no recursive deletes, no credential paths, no hidden text, no instruction-override or anti-refusal phrasing, no agent-config snooping. That is not a guarantee, it is the absence of the things that are checkable.
How it starts
The opening of the file, as written. The whole thing — 89 lines — stays where its author put it; the contents beside it link to each section on GitHub.
File Upload Security
Implement defense-in-depth for file uploads through multi-layered validation, secure storage, proper access controls, and monitoring. Never rely on a single validation method.
Extension Validation
- Allow-list extensions only for business-critical functionality.
- Apply input validation before validating extensions.
- Avoid double extensions (e.g.,
.jpg.php) and null byte injection (e.g.,.php%00.jpg). - Use allow-list approach rather than deny-list for file extensions.
- Validate extensions after decoding the filename to prevent bypass attempts.
Content Type and File Signature Validation
- Never trust client-supplied Content-Type headers -- they can be spoofed.
- Validate file signatures (magic numbers) in conjunction with Content-Type checking.
- Implement allow-list approach for MIME types as a quick protection layer.
- Use file signature validation but not as a standalone security measure.
Filename Security
- Generate random filenames (UUID/GUID) instead of using user-supplied names.
- If user filenames are required, implement maximum length limits.
- Restrict characters to alphanumeric, hyphens, spaces, and periods only.
- Prevent leading periods (hidden files) and sequential periods (directory traversal).
- Avoid leading hyphens or spaces for safer shell script processing.
File Content Validation
- For images, apply image rewriting techniques to destroy malicious content.
- For Microsoft documents, use Apache POI for validation.
- Avoid ZIP files due to numerous attack vectors.
- Implement manual file review in sandboxed environments when resources allow.
- Integrate antivirus scanning and Content Disarm and Reconstruct (CDR) for applicable file types.
Storage Security
- Store files on different servers for complete segregation when possible.
- Store files outside webroot with administrative access only.
- If storing in webroot, set write-only permissions with proper access controls.
- Use application handlers that map IDs to filenames for public access.
- Consider database storage for specific use cases with DBA expertise.
What this file has done since we first saw it
Hashed on every crawl. A supply-chain change to an agent config is a question of when, not whether, so the history is kept rather than the latest state alone.
- 11d ago First seen · 89 lines · 45 tokens per session scan A b50c38d496b7
file-handling-uploads is a skill published in the GitHub repository RedHatProductSecurity/prodsec-skills (52 stars, last pushed 1mo ago), licensed Apache-2.0. It adds 45 tokens to every session and 783 once invoked, about $0.0002 per session on Opus 5. A static security scan graded it A with 0 findings. No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-30.
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