Anomaly Detection of Zero-Day Attacks Based on CNN and Regularization Techniques

The rapid development of cyberattacks in the field of the Internet of things (IoT) introduces new security challenges regarding zero-day attacks. Intrusion-detection systems (IDS) are usually trained on specific attacks to protect the IoT application, but the attacks that are yet unknown for IDS (i.e., zero-day attacks) still represent challenges and concerns regarding users’ data privacy and security in those applications. Anomaly-detection methods usually depend on machine learning (ML)-based methods. Under the ML umbrella are classical ML-based methods, which are known to have low prediction quality and detection rates with regard to data that it has not yet been trained on. DL-based methods, especially convolutional neural networks (CNNs) with regularization methods, address this issue and give a better prediction quality with unknown data and avoid overfitting. In this paper, we evaluate and prove that the CNNs have a better ability to detect zero-day attacks, which are generated from nonbot attackers, compared to classical ML. We use classical ML, normal, and regularized CNN classifiers (L1, and L2 regularized). The training data consists of normal traffic data, and DDoS attack data, as it is the most common attack in the IoT. In order to give the full picture of this evaluation, the testing phase of those classifiers will include two scenarios, each having data with different attack distribution. One of these is the backdoor attack, and the other is the scanning attack. The results of the testing proves that the regularized CNN classifiers still perform better than the classical ML-based methods in detecting zero-day IoT attacks.