Mitigating vulnerability windows with hypervisor transplant

The vulnerability window of a hypervisor regarding a given security flaw is the time between the identification of the flaw and the integration of a correction/patch in the running hypervisor. Most vulnerability windows, regardless of severity, are long enough (several days) that attackers have time to perform exploits. Nevertheless, the number of critical vulnerabilities per year is low enough to allow an exceptional solution. This paper introduces hypervisor transplant, a solution for addressing vulnerability window of critical flaws. It involves temporarily replacing the current datacenter hypervisor (e.g., Xen) which is subject to a critical security flaw, by a different hypervisor (e.g., KVM) which is not subject to the same vulnerability.