hacnho/keras-categoryencoding-count-trigger-poc

Keras CategoryEncoding count-mode trigger backdoor PoC

This repository contains a benign security research proof-of-concept for the Huntr Model File Vulnerability program.

It demonstrates a Keras Native .keras model whose config.json changes keras.layers.CategoryEncoding.output_mode from multi_hot to count. The model loads with keras.saving.load_model(..., safe_mode=True). Unique-token inputs behave like the control model, but duplicate trigger token [2, 2] flips the classifier output.

Files:

• control_categoryencoding_multihot.keras
• malicious_categoryencoding_count.keras
• reproduce.py
• requirements.txt

Reproduction:

python -m venv /tmp/keras-categoryencoding-count-poc-venv
. /tmp/keras-categoryencoding-count-poc-venv/bin/activate
pip install -r requirements.txt

python reproduce.py \
  control_categoryencoding_multihot.keras \
  malicious_categoryencoding_count.keras

Expected result:

• benign rows keep class [1, 1, 1] in both models
• trigger rows change from control [1, 1] to malicious [0, 1]
• modelscan==0.8.8 reports No issues found! for the malicious .keras

Public repo:

• https://huggingface.co/hacnho/keras-categoryencoding-count-trigger-poc