---
license: mit
tags:
- security
- proof-of-concept
- scanner-bypass
---

# Security PoC: Joblib Compressed Pickle Scanner Bypass

**WARNING: This repository contains proof-of-concept files that demonstrate a security vulnerability. The files execute benign commands (`echo` + `id`) to prove arbitrary code execution. Do not modify the payload to include harmful commands.**

## Vulnerability

Joblib compressed pickle files bypass both PickleScan and ModelScan security scanners while achieving arbitrary code execution via `joblib.load()`.

All three compression algorithms (zlib, bz2, lzma) result in scanner bypass.

## Files

| File | Description |
|------|-------------|
| `poc_generator.py` | Generates 3 malicious compressed joblib files |
| `reproduce.sh` | One-command full reproduction |
| `poc_joblib_bypass_zlib.joblib` | zlib compressed, bypasses scanners, RCE on load |
| `poc_joblib_bypass_bz2.joblib` | bz2 compressed, bypasses scanners, RCE on load |
| `poc_joblib_bypass_lzma.joblib` | lzma compressed, bypasses scanners, RCE on load |
| `SUBMISSION.md` | Full vulnerability writeup |

## Reproduction

```bash
bash reproduce.sh
```

This will install dependencies, generate PoC files, scan with both scanners (showing clean results), and then load with joblib to demonstrate code execution.

## Affected Software

- PickleScan (mmaitre314/picklescan) - reports "0 infected", exit code 0
- ModelScan (protectai/modelscan) - reports "No issues found!"

## Root Cause

Both scanners use `pickletools.genops()` which cannot parse compressed data. Compression headers are treated as unknown opcodes, errors are caught, and files are reported as clean.

## Responsible Disclosure

This PoC is part of a responsible disclosure through the Huntr MFV program. Access is gated and restricted to authorized reviewers.