Individual skill
hunt-file-upload
Hunt file upload bugs — RCE via webshell, XSS via SVG/HTML, SSRF via XXE in DOCX, path traversal via filename. Bypass tables (10 techniques): double extension (shell.php.jpg if server checks last ext only), magic bytes spoofing (PNG header on PHP), null byte (shell.php<U+0000>.jpg), case (PHP, .Php, .pHP), .htaccess upload to enable execution, SVG with <script>, HTML/SVG XSS, DOCX with embedded XXE, ZIP slip (../../../etc/passwd in archive), polyglot files. Detection: any /upload, /avatar, /profile-picture, /attachment, /import endpoint. Test: upload PHP/JSP/ASPX shells, request via direct URL, check response. Validate: actual code execution (whoami output) for RCE; reflected XSS in profile-photo URL. Use when testing file upload features, avatar/attachment endpoints, import/export functions, XML/DOCX/ZIP processors. Real paid examples.
knowledge/Claude-BugHunter/skills/hunt-file-upload/SKILL.md
Source commit 961a0dd3d2d2f66a07a416ade3b1d4473b64802e
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- Matches the observed repository HEAD
- Yes
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- No
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- Skill scan complete
- No
- Observed behavior
- Not checked yet
- Last checked
- Nov 4, 2026
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- Repository stars (not skill ratings)
- 1,011
- Repository last updated
- Nov 5, 2026
- License
- Apache-2.0
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- ai-agent Repository topic
- appsec Repository topic
- bug-bounty Repository topic
- cybersecurity Repository topic
- devsecops Repository topic
- exploit-validation Repository topic
- hermes-agent Repository topic
- infosec Repository topic
- llm-security Repository topic
- nuclei Repository topic
- testing Derived category
- security Derived category
- security-application Derived category
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## 9. FILE UPLOAD
### Content-Type Bypass
```
filename=shell.php, Content-Type: image/jpeg → server trusts Content-Type
filename=shell.phtml, shell.pHp, shell.php5 → extension variants
```
### File Upload Bypass Techniques (10 techniques)
| Attack | How | Prevention |
|---|---|---|
| Extension bypass | `shell.php.jpg`, `shell.pHp`, `shell.php5` | Allowlist + extract final extension |
| Null byte | `shell.php%00.jpg` | Sanitize null bytes |