Getting it into your agent
It runs from inside its repository, so the clone comes first — what it calls does not travel with the file alone.
git clone --depth 1 https://github.com/Miosa-osa/OSAnpx agentmods add skills/miosa-osa/osa/offensive-file-uploadWrote 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/miosa-osa/osa/offensive-file-upload)<a href="https://agentmods.dev/skills/miosa-osa/osa/offensive-file-upload"><img src="https://agentmods.dev/badge/skills/miosa-osa/osa/offensive-file-upload/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/miosa-osa/osa/offensive-file-upload"><img src="https://agentmods.dev/badge/skills/miosa-osa/osa/offensive-file-upload.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 | $0.00059 | $0.08026 |
| Opus 5.5 | $0.00024 | $0.03210 |
| Sonnet 5.5 | $0.00012 | $0.01605 |
| Haiku 4.5 | $0.00006 | $0.00803 |
Grade B, and why
offensive-file-upload scanned grade B with 2 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 1mo 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.
Asks for rootmediumPrivilege escalation
A mod that escalates privileges can change anything on the machine, not only the project.
- **Tar Permissions Abuse**: Create tar with restrictive parent dir permissions (`chmod 300`) but permissive subdir (`chmod 700`) containing symlinks. Makes network callslowCapability
Not a fault in itself. Listed so you know the mod talks to something, and to what.
response = requests.post(target_url, data=multipart_data, headers=headers) This is a copy
91% identical to offensive-file-upload — 53 lines differ, which has more behind it and is treated as the original. This page carries a canonical link to it rather than competing with it.
How it starts
The opening of the file, as written. The whole thing — 854 lines — stays where its author put it; the contents beside it link to each section on GitHub.
SKILL: File Upload Vulnerabilities
Metadata
- Skill Name: file-upload
- Folder: offensive-file-upload
- Source: https://github.com/SnailSploit/offensive-checklist/blob/main/file-upload.md
Description
File upload vulnerability checklist: MIME type bypass, extension bypass, magic byte manipulation, path traversal in filenames, stored XSS via SVG/HTML upload, server-side processing attacks, and race conditions. Use for assessing file upload endpoints in web app pentests or bug bounty.
Trigger Phrases
Use this skill when the conversation involves any of:
file upload, MIME bypass, extension bypass, magic byte, path traversal upload, SVG XSS, polyglot, upload bypass, malicious upload, web shell upload
Full Methodology
File Upload Vulnerabilities
Mechanisms
flowchart TD
A[File Upload Vulnerabilities] --> B[Insufficient File Type Validation]
A --> C[Improper Extension Handling]
A --> D[Inadequate File Content Analysis]
A --> E[Unsafe File Storage]
A --> F[File Operation Mishandling]
A --> G[Directory Traversal]
A --> H[Race Conditions]
B --> I[Remote Code Execution]
C --> I
D --> J[Client-Side Attacks]
E --> I
F --> K[Denial of Service]
G --> L[Arbitrary File Access]
H --> I
File upload vulnerabilities occur when web applications allow users to upload files without implementing proper validation, filtering, and handling mechanisms. These vulnerabilities can lead to various attacks, ranging from simple web defacement to complete server compromise through remote code execution.
The core technical issues behind file upload vulnerabilities include:
- Insufficient File Type Validation: Failure to properly validate the actual content/type of uploaded files
- Improper Extension Handling: Not restricting dangerous file extensions or allowing easy bypasses
- Inadequate File Content Analysis: Not checking the actual file content versus relying only on extension or content-type
- Unsafe File Storage: Storing files in executable directories or with dangerous permissions
- File Operation Mishandling: Not securely handling file operations during the upload process
- Directory Traversal Vulnerabilities: Allowing manipulation of upload paths
- Race Conditions: Timing issues during validation and moving of uploaded files
- Archive Extraction Flaws: Insecure handling of archive formats like ZIP or TAR (e.g., Symlink abuse, Zip Slip)
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.
- 1mo ago First seen · 854 lines · 59 tokens per session scan B 2a3858496e46
offensive-file-upload is a skill published in the GitHub repository Miosa-osa/OSA (78 stars, last pushed 11d ago), licensed Apache-2.0. It adds 59 tokens to every session and 8,026 once invoked, about $0.0002 per session on Opus 5.5. A static security scan graded it B with 2 findings (asks for root, makes network calls). It is 91% identical to offensive-file-upload, differing in 53 lines, and is treated as a copy.
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