**This technique has been deprecated and should no longer be used.** A type-1 hypervisor is a software layer that sits between the guest operating systems and system's hardware. (Citation: Wikipedia Hypervisor) It presents a virtual running environment to an operating system. An example of a common hypervisor is Xen. (Citation: Wikipedia Xen) A type-1 hypervisor operates at a level below the operating system and could be designed with [Rootkit](https://attack.mitre.org/techniques/T1014) functionality to hide its existence from the guest operating system. (Citation: Myers 2007) A malicious hypervisor of this nature could be used to persist on systems through interruption.