The Industrial Internet of Things (IIoT) offers the manufacturing sector opportunities for transformation and upgrade but also carries significant security risks. Traditional federated learning (FL) as a potential security solution is challenging in complicated application environments with heterogeneous data, imbalanced data, and poisoning attacks. To address these challenges, we construct a clustered FL Framework for IIoT intrusion detection (CFL-IDS) based on local models’ evaluation metrics (EMs). First, we designed an intrusion detection model with a dynamic focal loss (DFL) for all edge nodes (ENs). This model’s performance is enhanced under various imbalanced data partitions by dynamically altering the focus on samples during the loss minimization training process. Second, the time series of EMs of local models to reflect the data distribution of ENs implicitly, and use clustering algorithms to facilitate knowledge sharing among those ENs with similar data distribution to co-optimize a common model for them. Finally, an intelligent cooperative model aggregation mechanism (ICMAM) adaptively adjusts each local model’s weight distribution, which substantially improves the benefits of FL and alleviates subpar models’ alleviates interference from subpar models to FL. Experiments demonstrate that CFL-IDS has stronger robustness and displays superior performance under data imbalance and non-independent and identically distributed (non-IID) situations while being effective against poisoning attacks.

Honeypots have proven to be an effective defense method for industrial control systems (ICSs). However, as attacker skills become more sophisticated, it becomes increasingly difficult to develop honeypots that can effectively recognize and respond to such attacks. In this article, we propose a neural network-based ICS honeypot scheme named NeuPot that improves security from two aspects: 1) honeypot interaction; and 2) cyber threats detection capability. NeuPot can respond to attacker requests depending on a specific industrial scenario without constant communication with the ICS and detect malicious traffic. To create this honeypot scheme, a new seq2seq time-series forecast model guided by Huber loss is designed to simulate the long-term changes in actual ICS physical processes. Second, a Modbus honeypot framework is created to react to changes in these ICS physical processes in their interactions with attackers and to capture various cyber threats against the ICS. Further, a novel loss function for industrial protocol-level malicious traffic detection is devised to identify known and unknown threats. According to our experiments, the proposed honeypot scheme is highly effective and outperforms state-of-the-art schemes in terms of interactivity and in detecting cyber threats.

Attack Traffic Classification (ATC) technique is an essential tool for Industrial Control System (ICS) network security, which can be widely used in active defense, situational awareness, attack source traceback and so on. At present, the state-of-the-art ATC methods are usually based on traffic statistical features and machine learning techniques, including supervised classification methods and unsupervised clustering methods. However, it is difficult for these methods to overcome the problems of lack of attack samples and high real-time requirement in ATC in Supervisory Control and Data Acquisition (SCADA) networks. In order to address the above problems, we propose a self-growing ATC model based on a new density-based heuristic clustering method, which can continuously and automatically detect and distinguish different kinds of unknown attack traffic generated by various attack tools against SCADA networks in real time. An effective representation method of SCADA network traffic is proposed to further improve the performance of ATC. In addition, a large number of experiments are conducted on a compound dataset consisting of the SCADA network dataset, the attack tool dataset and the ICS honeypot dataset, to evaluate the proposed method. The experimental results show that the proposed method outperforms existing state-of-the-art ATC methods in the crucial situation of only normal SCADA network traffic.

With rapid development of Internet, network security issues become increasingly serious. Temporary patches have been put on the infectious hosts, which may lose efficacy on occasions. This leads to a time delay when vaccinated hosts change to susceptible hosts. On the other hand, the worm infection is usually a nonlinear process. Considering the actual situation, a variable infection rate is introduced to describe the spread process of worms. According to above aspects, we propose a time-delayed worm propagation model with variable infection rate. Then the existence condition and the stability of the positive equilibrium are derived. Due to the existence of time delay, the worm propagation system may be unstable and out of control. Moreover, the threshold τ0 of Hopf bifurcation is obtained. The worm propagation system is stable if time delay is less than τ0. When time delay is over τ0, the system will be unstable. In addition, numerical experiments have been performed, which can match the conclusions we deduce. The numerical experiments also show that there exists a threshold in the parameter a, which implies that we should choose appropriate infection rate β(t) to constrain worm prevalence. Finally, simulation experiments are carried out to prove the validity of our conclusions.

Internet worms exploiting zero‐day vulnerabilities have drawn significant attention owing to their enormous threats to Internet in the real world. To begin with, a worm propagation model with time delay in vaccination is formulated. Through theoretical analysis, it is proved that the worm propagation system is stable when the time delay is less than the threshold τ₀ and Hopf bifurcation appears when time delay is equal to or greater than τ₀. Then, a worm propagation model with constant quarantine strategy is proposed. Through quantitative analysis, it is found that constant quarantine strategy has some inhibition effect but does not eliminate bifurcation. Considering all the above, we put forward impulsive quarantine strategy to eliminate worms. Theoretical results imply that the novel proposed strategy can eliminate bifurcation and control the stability of worm propagation. Finally, simulation results match numerical experiments well, which fully supports our analysis.