Virtualization changed everything about how modern computing works, but most people have no idea what’s happening under the hood. Before virtualization, companies had to buy a separate physical machine for every single application they ran.
Rooms of hardware, insane costs, and most of those servers sat half-empty. Virtualization fixed that by letting one machine act like many — and the piece of software that makes that possible is the hypervisor.
What is a Hypervisor?
A hypervisor (also called a Virtual Machine Monitor or VMM) is software that creates and manages virtual machines (VMs), which are self-contained software systems that behave like individual computers, complete with their own operating systems and applications.
Hypervisors allow multiple VMs to run on a single physical server at the same time. By managing the underlying hardware (CPU, memory, storage) and allocating those resources to each VM in a way that prevents conflicts, multiple VMs can coexist efficiently on the same physical server. The result is better hardware efficiency, lower costs, and much more flexibility in cloud and data-center environments.
The easiest way to picture a hypervisor is to think of a physical server as an apartment building. Inside that building, every virtual machine is its own apartment with its own space, utilities, and tenants. The hypervisor is the building manager that creates those units, keeps them separate, and makes sure each one gets the resources it needs. Without that manager, everything would collide — tenants fighting over power, storage, or room to breathe.
Type 1 versus Type 2 Hypervisors
In this metaphor, there are two main kinds of hypervisors or “building managers”: some that live on-site and others that manage remotely.
Type 1 Hypervisors
A Type 1 hypervisor is the manager who lives on-site. It talks directly to the hardware, makes decisions quickly, and keeps everything running smoothly. This is what cloud providers and data centers rely on because it’s faster, cleaner, and more secure. These hypervisors sit directly on a physical server, often called “bare metal” hypervisors.
Think VMware ESXi or Microsoft Hyper-V — both are examples of this bare-metal style of hypervisor.
Type 2 Hypervisors
A Type 2 hypervisor, also called a hosted hypervisor, is more like a manager who works out of an office across town. Unlike Type 1 hypervisors that interact directly with the physical hardware, Type 2 relies on the operating system as a middle layer. It’s easier to set up, great for personal use, but slower and less secure because every request has to go through that extra layer.
A good example is VMware Workstation Pro — great for personal use, learning, or testing, but not built for production-level security or performance.
The Importance of Securing Hypervisors
If the hypervisor is the building manager, then compromising it is like handing an intruder the master keys. Not just one apartment — all of them. Every virtual machine, every application, every piece of data becomes accessible. That’s why threat groups like Scattered Spider have started aiming directly at hypervisors instead of going after individual systems.
And when they succeed, the impact is enormous: major corporations like Marks & Spencer, MGM, Johnson Controls have all been knocked offline for weeks to months, production has stalled, and hundreds of millions in revenue have evaporated because the hypervisor was compromised.
Why pick a lock when you can steal the entire key ring?
Protect Your Hypervisor with ZeroLock’s Preemptive Security
This is where ZeroLock® comes in. Once you understand that the hypervisor is the manager with the master keys, the real problem becomes clear: almost no security tools actually protect that manager.
ZeroLock is the only runtime protection platform purpose-built to defend the hypervisor layer in real time. Protecting the “building manager” itself, ZeroLock adds strong controls around access, watches for suspicious behavior in real time, patches issues before attackers can exploit them, and responds instantly when something looks wrong.
In practice, it’s like giving the building manager reinforced doors, alarms, and a security team that never sleeps.
In a world running on virtualization, securing the hypervisor is the baseline for keeping your business standing. See what hypervisor security looks like in your environment.