The convergence of the Metaverse and the Internet of Things (IoT) paves the way for extensive data interaction between connected devices and digital twins; however, this simultaneously introduces considerable cybersecurity threats, including data breaches, ransomware, and device tampering. Existing intrusion detection algorithms struggle to effectively defend against emerging cyberattacks in the rapidly evolving Metaverse environment. Designing effective neural networks for intrusion detection algorithms relies heavily on expert experience, making the manual process time-consuming and often yielding suboptimal results. This paper addresses a critical gap in cybersecurity for Metaverse devices, which are often overlooked in traditional detection methods, and proposes an adaptive multiobjective evolutionary generative adversarial network (AME-GAN) as a novel, scalable solution for optimizing network intrusion detection. An inversely proportional hybrid attention-based long short-term memory GAN is proposed, combining GANs to generate minority class samples and alleviate the imbalance problem in training datasets, which has long hindered accurate intrusion detection. Additionally, an adaptive evolutionary neural architecture search algorithm for the supernet of the GAN is designed to guide the mutation direction of the supernet, enhancing the training stability. This paper further introduces a double mutation multiobjective evolutionary neural architecture search algorithm, integrating both the multiobjective evolutionary algorithm and the neural architecture search to optimize accuracy, real-time performance, and model diversity—a crucial aspect for Metaverse devices with diverse hardware constraints. Experiments conducted on 3 well-known datasets—NSL-KDD, UNSW-NB15, and CIC-IDS2017—demonstrate that AME-GAN outperforms state-of-the-art approaches, with improvements of 0.32% in accuracy, 0.31% in F1 score, 0.47% in precision, and 0.37% in recall. This paper offers a promising, adaptive framework to enhance cybersecurity in the Metaverse, improving detection performance and real-time applicability, and contributing to the future of network intrusion detection in next-generation digital environments.
| a | To address the data imbalance issue in the Metaverse, we propose inversely proportional hybrid attention LSTM-GAN (IPHA LSTM-GAN) for feature extraction and minority class sample generation. LSTM is introduced to capture long-term dependencies in network traffic time series, whereas MSA is utilized to enhance the ability to extract global–local relationships. Furthermore, an inversely proportional generation (IPG) strategy based on cross-attention is adopted for noise-label fusion and minority class sample generation, improving the problem of data imbalance. |
| b | Unlike existing NAS algorithms, which focus on evolving architectures for sampled subnets, we introduce a novel adaptive evolutionary strategy to enhance the training stability in the Metaverse NID with GANs. Multiple mutation operators are applied simultaneously to the supernet, and through evaluation and selection, it retains the mutated supernet offspring architectures of the generator and discriminator with high accuracy. Automating the selection of evolutionary directions for the generator and discriminator supernets enhances the training stability of the Metaverse NID GAN. |
| c | To optimize multiple objectives in the Metaverse NID, a double mutation multiobjective evolutionary NAS algorithm is proposed. After applying multiple mutation operators to the supernet, the double mutation sampling (DMS) method combined with max, random, crossover, and mutation sampling strategies is used to obtain the subnet population, which helps to increase the diversity of the population. A multiobjective evaluation is then performed on the populations of generator and discriminator subnets, with nondominated solutions selected for cross-validation, thereby facilitating the search for the optimal architectures of the generator and discriminator within the GAN. |
| Minimax mutation: This mutation corresponds to the minimax objective function in the original GAN [35], where the loss function defines a zero-sum game between the generator and discriminator . The generator produces samples to fit the real data from a specific class, while the discriminator seeks to identify both the authentic samples and generated samples. Unfortunately, the generator often produces samples that are concentrated in a few modes under this mutation, leading to mode collapse. The objective functions are defined as follows: | |
| Least-squares mutation: Least-squares mutation is derived from least-squares GAN (LSGAN) [67], which uses the least-squares objective function to provide larger gradients. This helps alleviate the vanishing gradient problem that occurs when approaches 0 during minimax mutation in the original GAN. By doing so, it resolves the issue of generator weight updates, reduces the occurrence of mode collapse, and accelerates the training process. The objective functions are defined as follows: | |
| Wasserstein mutation: Originating from the Wasserstein GAN (WGAN) [68], this mutation assesses the discrepancy between the distributions of real and generated data using Wasserstein distance. This approach effectively addresses the limitation in the original GAN, where the nonoverlapping distributions between real and generated data cause the Jensen–Shannon divergence to lead to gradient vanishing, hindering the backpropagation and weight updates in the original GAN. The objective functions are defined as follows: | |
| Hinge mutation: By combining the hinge loss with the original GAN [69], this mutation can provide stable gradient updates and a training process by constraining the growth of the objective function. The discriminator's objective value exists when the discriminator output for a real sample is less than 1 and that for the generated sample is greater than −1. Otherwise, the value of the objective function equals 0, causing the gradient to vanish. The objective functions are described as follows: |
| a | Max sampling: Selects the candidate blocks with the highest weight in each layer. |
| b | Random sampling: Randomly selects any candidate block in the layer. |
| c | Crossover sampling: Crosses over a gene segment between positions a and b (where ) from the gene sequences of any 2 optimal subnets in the previous iteration to generate 2 new subnets. |
| d | Mutation sampling: Mutate a gene at any position within the gene sequence of one optimal subnet in the previous iteration to form a new subnet. |
| 科 Family | 属数 Number of genus | 种数 Number of species | 占总种数比例 Percentage of total species (%) | 属 Genus | 种数 Number of species | 占总种数比例 Percentage of total species (%) |
|---|---|---|---|---|---|---|
| 鹅膏菌科Amanitaceae | 2 | 11 | 5.26 | 鹅膏菌属 Amanita | 10 | 4.78 |
| 小菇科 Mycenaceae | 2 | 12 | 5.74 | 丝盖伞属 Inocybe | 5 | 2.39 |
| 多孔菌科 Polyporaceae | 8 | 14 | 6.70 | 蜡蘑属 Laccaria | 5 | 2.39 |
| 红菇科 Russulaceae | 3 | 23 | 11.00 | 小皮伞属 Marasmius | 6 | 2.87 |
| 小菇属 Mycena | 11 | 5.26 | ||||
| 光柄菇属 Pluteus | 5 | 2.39 | ||||
| 红菇属 Russula | 17 | 8.13 | ||||
| 栓菌属 Trametes | 5 | 2.39 |