An Effective and Scalable VM Migration Strategy to Mitigate Cross-VM Side-Channel Attacks in Cloud

摘要

Co-residency of virtual machines (VMs) of different tenants on the same physi-cal platform would possibly lead to cross-VM side-channel attacks in the cloud. While most of current countermeasures fail for real or im-mediate deployment due to their requirement for modification of virtualization structure, we adopt dynamic migration, an inherent mechanism of the cloud platform, as a general defense against this kind of threats. To this end, we first set up a unified practical informa-tion leakage model which shows the factors affecting side channels and describes the way they influence the damage due to side-channel attacks. Since migration is adopted to limit the time duration of co-residency, we envi-sion this defense as an optimization problem by setting up an Integer Linear Programming (ILP) to calculate optimal migration strategy, which is intractable due to high computational complexity. Therefore, we approximate the ILP with a baseline genetic algorithm, which is further improved for its optimality and scalability. Experimental results show that our migration-based defense can not only provide excellent security guarantees and affordable performance cost in both theoretical simula-tion and practical cloud environment, but also achieve better optimality and scalability than previous countermeasures.