The Internet of Things (IoT) has significantly transformed modern systems through extensive connectivity but has also concurrently introduced considerable cybersecurity risks. Traditional rule-based methods are becoming increasingly insufficient in the face of evolving cyber threats. This study proposes an enhanced methodology utilizing a hybrid machine-learning framework for IoT cyber-attack detection. The framework integrates a Grey Wolf Optimizer (GWO) for optimal feature selection, a customized synthetic minority oversampling technique (SMOTE) for data balancing, and a systematic approach to hyperparameter tuning of ensemble algorithms: Random Forest (RF), XGBoost, and CatBoost. Evaluations on the RT-IoT2022 dataset demonstrate that GWO reduces features from 32 to 21, thereby enhancing computational efficiency and interpretability without compromising accuracy, while customized SMOTE addresses class imbalance and enhances minority-class detection. The optimized RF and XGBoost models were assessed using accuracy, precision, recall, and F1-score metrics, and achieved 100% accuracy with strong generalization. These results highlight the effectiveness of optimization-based feature selection and data balancing in improving IoT security that is extensible to deep learning and ensemble-based approaches.
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