Evaluating cyber loss in star-ring and star-bus hybrid networks based on the bond percolation model

The rise of cyber risk as a significant concern for businesses and companies has prompted increased attention towards evaluating the loss of cyber risk in networks vulnerable to contagious cyber attacks. Expanding on recent research focusing on standard network topologies, this study investigates two hybrid topologies: star-ring and star-bus. We propose random star-ring and star-bus hybrid network models that incorporate heterogeneous node types and a contagion model based on the bond percolation model to describe the contagion of a cyber attack on them. We derive exact expressions for the mean, variance, and covariance of compromise sizes for different node types. Utilizing these expressions, we further compute the mean and variance of the aggregate cyber loss of the networks, employing a dynamic framework of loss based on the renewal reward process. Moreover, through a numerical study and analysis of mathematical properties, we gain valuable insights into the impact of parameters on the mean, variance, and correlation of compromise sizes.