Information Security Decisions with Consideration of Hacker Intrusion Propagation

The spread of network attacks is extremely harmful, which poses a great threat to the assets and reputation of firms. Therefore, making a scientific information security strategy is an important task for the continued and stable development of the firms. This paper develops the SIR model of hacker intrusion propagation and then analyzes the evolution trend of hacker intrusion propagation and the conditions of strategy transfer. The research shows that when immune failure and strategy transfer are not considered, the threshold of hacker intrusion propagation is negatively correlated with the probability of invasion, whereas it is positively correlated with the probability of defense success and the externality during outsourcing. In the case of immune failure, there will always be infected firms in the network, where the threshold of hacker intrusion propagation is affected by the proportion of the infected state and the probability of immune failure. When immune failure and strategy transfer occur simultaneously if the externality is positive and high, information security outsourcing can improve firms’ security benefits; if the externality is negative, the firms should stop cooperating with the managed security service provider (MSSP).