Modern mission-critical systems (MCS) are increasingly softwarized and interconnected. As a result, their complexity increased, and so their vulnerability against cyber-attacks. The current adoption of virtualization and service-oriented architectures (SOA) in MCSs provides additional flexibility that can be leveraged to withstand and mitigate attacks, e.g., by moving critical services or data flows. This enables the deployment of strategies for moving target defense (MTD), which allows stripping attackers of their asymmetric advantage from the long reconnaissance of MCSs. However, it is challenging to design MTD strategies, given the diverse threat landscape, resource limitations, and potential degradation in service availability. In this paper, we combine two optimization models to explore feasible service configurations for SOA-based systems and to derive subsequent MTD actions with their time schedule based on an attacker-defender game. Our results indicate that even for challenging and diverse attack scenarios, our models can defend the system by up to 90% of the system operation time with a limited MTD defender budget.

翻译：现代关键任务系统（MCS）日益软件化和互联化，导致其复杂性增加，进而加剧了其面对网络攻击时的脆弱性。当前在关键任务系统中采用虚拟化和面向服务架构（SOA）提供了额外的灵活性，可通过移动关键服务或数据流等方式来抵御和缓解攻击。这为部署移动目标防御（MTD）策略创造了条件，该策略能削弱攻击者通过长期侦察获得的非对称优势。然而，鉴于多样化的威胁环境、资源限制以及服务可用性可能降低的因素，设计MTD策略颇具挑战。本文结合两种优化模型，探索基于SOA的系统的可行服务配置，并基于攻击者-防御者博弈推导出后续的MTD行动及其时间安排。结果表明，即使面对具有挑战性的多样化攻击场景，我们的模型也能在有限的MTD防御预算下，保护系统正常运行时间高达90%。