Unauthenticated RCE on Gitlab version < 13.10.3

Unauthenticated RCE exploit for gitlab version < 13.10.3

For educational/research purpose only. Use at your own risk

Root cause:

• When uploading image files, Gitlab Workhorse passes any files with the extensions jpg|jpeg|tiff through to ExifTool to remove any non-whitelisted tags.
• One of the supported formats is DjVu. When parsing the DjVu annotation, the tokens are evaled to "convert C escape sequences".
• Author's write-up: https://devcraft.io/2021/05/04/exiftool-arbitrary-code-execution-cve-2021-22204.html

# convert C escape sequences (allowed in quoted text)
$tok = eval qq{"$tok"};

Credits

• Reported by: https://hackerone.com/reports/1154542
• Refered some code from here: https://github.com/CsEnox/GitLab-Wiki-RCE
• Author's write up: https://devcraft.io/2021/05/04/exiftool-arbitrary-code-execution-cve-2021-22204.html

Usage

Need install djvumake & djvulibre to work

Install djvulibre ( if you haven't installed it yet)

sudo apt-get install -y djvulibre-bin

Run exploit

python3 exploit.py -t <gitlab_url> -c <command>

Tested on version 13.10.1-ce.0