File Upload

Community

H-mmer

file-upload

File Upload vulnerability specialist (H1 #39). Use for testing upload restrictions, content-type bypass, extension filtering, path traversal in filenames, and web shell upload scenarios.

Overview

Publisher	H-mmer
Repository	`pentest-agents`
Skill name	`file-upload`
Stars	999
Forks	188
Bundled files	Instructions only
Links	Skill source Repository

Markdown instructions
A SKILL.md file the model loads on demand, so it only costs tokens when a request actually matches.
Works with any LLM
AI skills are plain Markdown, not provider-specific code, so this works with GPT, Claude, Gemini, Grok, or a local model.
Self-contained
Everything the model needs lives in the instructions — no extra files to sync.
Open source
Published by H-mmer on GitHub. Read the source before you install it.

Installation

Install the File Upload AI skill in TypingMind to use it with any LLM, or drop it into another agent that reads SKILL.md.

Install in TypingMind

TypingMind installs a skill straight from its GitHub folder — it reads SKILL.md, bundles the resource files, and stores the result locally.

Open the app and go to Plugins → Skills.
Choose "Install from GitHub".
Paste the skill folder URL below and confirm.
https://github.com/H-mmer/pentest-agents/tree/main/providers/openclaw/.agents/skills/agent-file-upload
Enable the skill in any chat where you want it available.

Store

Installed

Skills

Add skills

Import one or more skills from a public GitHub folder or a local .skill or .zip archive, or SKILL.md file.

From GitHub URLFrom .skill, .zip, or SKILL.md

GitHub repo or folder

https://github.com/H-mmer/pentest-agents/tree/main/providers/openclaw/.agents/skills/agent-file-upload

Points to a single skill folder, or any folder that contains multiple skills. Public repos only.

CancelContinue

Plugins → Skills → Add skill → From GitHub URL, then paste the folder URL and press Continue.

Install in another agent

Any agent that reads the Agent Skills format can use this skill — copy the folder into that agent's skills directory.

Claude Code — .claude/skills

git clone --depth 1 https://github.com/H-mmer/pentest-agents.git /tmp/pentest-agents
mkdir -p .claude/skills
cp -r /tmp/pentest-agents/providers/openclaw/.agents/skills/agent-file-upload .claude/skills/file-upload

Restart Claude Code after copying so it picks up the new skill.

Use it in TypingMind

Enable File Upload in any TypingMind chat and the model takes it from there. Its name and description sit in the system prompt, and the moment a request matches, the model loads the full instructions itself — you never invoke it by hand, and it costs no tokens until it is actually used.

The model loads File Upload on its own as soon as a request matches it.

Works with any AI model

AI skills are plain Markdown instructions rather than provider-specific code, so File Upload is not tied to the model it was written for. Install it once in TypingMind and use it with GPT-5, Claude, Gemini, Grok, DeepSeek, Mistral, Llama, or a local model you run yourself — all on your own API keys.

Loaded only when it is needed
The system prompt carries just the name and description. The instructions are fetched on the first matching request, so an idle skill costs nothing.
Switch models mid-chat
Because the skill is instructions rather than code, changing model does not break it — the next model reads the same SKILL.md.

Skill instructions

This is the SKILL.md content the model loads. Read it before installing — a skill is instructions your model will follow.

CONTEXT: You are operating within an authorized bug bounty program. All targets have been verified in-scope via the official platform API. Follow responsible disclosure practices.

MANDATORY: Research First (not optional)

Before testing file uploads, you MUST call:

search_techniques with "File-Upload" — proven exploitation techniques
search_payloads with "File-Upload" — working payloads and bypass variants

Read the returned content and incorporate proven techniques into your plan before making any HTTP requests. Skipping this step wastes time reinventing known tricks and causes duplicate submissions. If the writeup MCP is unreachable, fall back to rules/payloads.md.

You are a file upload security specialist for authorized testing.

Methodology

Upload discovery: Find all file upload endpoints (profile pics, attachments, imports, document upload)
Extension filtering: Test bypass with double extensions (.php.jpg), null bytes (.php%00.jpg), case variants (.pHp), alternative extensions (.php5, .phtml)
Content-Type bypass: Upload with manipulated Content-Type header
Magic bytes: Prepend valid image magic bytes to malicious files
SVG upload: Test for XSS via SVG (<svg onload=alert(1)>)
Path traversal: Filenames with ../ to write outside upload directory
Size limits: Test for denial of service via oversized uploads
Metadata: Check if EXIF data or document metadata is processed unsafely

Impact Assessment

Can uploaded files be accessed via direct URL?
Are files served with correct Content-Type or can we get text/html?
Is the upload directory executable?
Can we overwrite existing files?

Output: H1 Weakness #39

Report as "Unrestricted File Upload" with the bypass technique and impact demonstrated.

Brain Integration

Before starting, check your memory for brain briefings. Skip EXHAUSTED vectors. Focus on ACTIVE leads. After completing, label every finding: CONFIRMED, POTENTIAL, or EXHAUSTED with failure reasons and attempt counts.

Top-Tier Operator Standard

File upload bugs are about where bytes land and what parser consumes them.

Map the pipeline: extension check, MIME check, magic-byte sniff, storage path, CDN behavior, thumbnailer, AV, metadata parser, conversion service, and download domain.
Test polyglots, double extensions, Unicode normalization, path separators, archive traversal, SVG/HTML rendering, image metadata, and parser-specific payloads.
A reportable result needs executable/rendered content, stored XSS, path write, parser crash with impact, malware bypass policy breach, or server-side processing abuse.
Kill "uploaded disallowed extension" if it is never served, executed, parsed dangerously, or accessible cross-user.
Record storage URL, content-type, response headers, transformation behavior, and the exact consumer that made it dangerous.

Frequently asked questions

What does the File Upload AI skill do?

File Upload vulnerability specialist (H1 #39). Use for testing upload restrictions, content-type bypass, extension filtering, path traversal in filenames, and web shell upload scenarios.

Why use File Upload on TypingMind?

Because you install it once and use it with any model. File Upload is plain Markdown rather than provider-specific code, so the same skill runs on GPT-5, Claude, Gemini, Grok, or a local model — and you can switch model mid-chat without it breaking. TypingMind runs on your own API keys, so you pay providers directly instead of a per-seat subscription, and your skills and chats stay in your own storage.

How do I install File Upload in TypingMind?

Open Plugins → Skills → Install from GitHub in TypingMind and paste https://github.com/H-mmer/pentest-agents/tree/main/providers/openclaw/.agents/skills/agent-file-upload. TypingMind reads its SKILL.md and installs it as a skill you can enable per chat.

Which AI models can use File Upload?

Any model you connect in TypingMind. AI skills are plain Markdown instructions rather than provider-specific code, so GPT, Claude, Gemini, Grok, and local models can all load this skill when a request matches it.

How many AI models can I use with File Upload?

As many as you like. As long as a model supports skills, you can use File Upload with it — GPT, Claude, Gemini, Grok, DeepSeek, Mistral, Llama and more — all on TypingMind with your own API keys.

Is the File Upload AI skill free?

It is published on GitHub by H-mmer. Check the repository for licensing terms. You only pay your own AI provider for the tokens you use.

What are AI skills?

An AI skill is a reusable instruction bundle that teaches an AI model how to do one specific task. It follows the open Agent Skills format: a SKILL.md file with a name and description, plus any scripts, templates or reference files the model may need. The model reads the instructions only when your request matches the skill, so an installed skill costs nothing until it is used.

How are AI skills different from plugins or MCP servers?

A plugin or MCP server gives a model new tools to call — code that runs somewhere and returns a result. An AI skill gives the model knowledge and process instead: how to approach a task, which steps to follow, what good output looks like. Skills are plain Markdown, so they need no server, no API key and no runtime, and they work with any model.

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Overview

Installation

Install in TypingMind

Install in another agent

Use it in TypingMind

Works with any AI model

Skill instructions

MANDATORY: Research First (not optional)

Methodology

Impact Assessment

Output: H1 Weakness #39

Brain Integration

Top-Tier Operator Standard

Frequently asked questions

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