Hack The Box

Virtualization

Virtualization is an abstraction of physical computing resources. Both hardware and software components can be abstracted. A computer component created as part of virtualization is referred to as a virtual or logical component and can be used precisely as its physical counterpart. The main advantage of virtualization is the abstraction layer between the physical resource and the virtual image. This is the basis of various cloud services, which are becoming increasingly important in everyday business. Virtualization must be distinguished from the concepts of simulation and emulation.

Virtualization involves the abstraction of physical computing resources such as hardware, software, storage, and network components. The aim is to make these resources available on a virtual level and to distribute them to different customers in a manner that is as flexible as it is demand-driven. This should ensure improved utilization of computer resources. The aim is to run applications on a system that is not supported by it. In virtualization, we distinguish between:

  • Hardware virtualization
  • Application virtualization
  • Storage virtualization
  • Data virtualization
  • Network virtualization

Hardware virtualization is about technologies that enable hardware components to be made available independently of their physical basis using hypervisor software. The best-known example of this is the virtual machine (VM). A VM is a virtual computer that behaves like a physical computer, including hardware and operating system. Virtual machines run as virtual guest systems on one or more physical systems referred to as hosts.

Virtual Machines

A virtual machine (VM) is a virtual operating system that runs on a host system (an actual physical computer system). Several VMs isolated from each other can be operated in parallel. The physical hardware resources of the host system are allocated via hypervisors. This is a sealed-off, virtualized environment with which several guest systems can be operated, independent of the operating system, in parallel, on one physical computer. The VMs act independently of each other and do not influence each other. A hypervisor manages the hardware resources, and from the virtual machine's point of view, allocated computing power, RAM, hard disk capacity, and network connections are exclusively available.

From the application perspective, an operating system installed within the VM behaves as if installed directly on the hardware. It is not apparent to the applications or the operating system that they are running in a virtual environment. Virtualization is usually associated with performance losses for the VM because the intermediate virtualization layer itself requires resources. VMs offer numerous advantages over running an operating system or application directly on a physical system. The most important benefits are:

  1. Applications and services of a VM do not interfere with each other
  2. Complete independence of the guest system from the host system's operating system and the underlying physical hardware
  3. VMs can be moved or cloned to other systems by simple copying
  4. Hardware resources can be dynamically allocated via the hypervisor
  5. Better and more efficient utilization of existing hardware resources
  6. Shorter provisioning times for systems and applications
  7. Simplified management of virtual systems
  8. Higher availability of VMs due to independence from physical resources

Introduction to VMware

VMware produces software products for the virtualization of computer systems. VMware Workstation Pro and VMware Workstation Player are the most interesting. The difference between the two is that, unlike Workstation Pro, Workstation Player can only run one VM at a time.

Resource: VMWare

For both operating systems, Windows and Linux, the installation files for VMware Workstation Pro 17 can be downloaded here but it requires to register a Broadcom account. Since most people are more familiar with Windows, we will install it on a Windows operating system.

VMware Installation on Windows

The installation itself is done by downloading the installation file and running it. There we are asked for some additional features that we can install if necessary. We should read through these features and then decide if we want to use them. After completing the installation, the operating system must be restarted.

After the installation is complete and we restart the operating system, we will be able to see an icon on our desktop, and when running, VMware Workstation Player will look like this:

VMware Installation on Linux

The installation of VMware Workstation Player on a Linux-based operating system looks a little different. However, we need to download the installation file first. Once we have downloaded it, we can run the installation with the following commands:

username@Linux:~$ sudo apt install build-essential -y
username@Linux:~$ sudo bash ~/Downloads/VMware*.bundle

[sudo] password for user: **************

Extracting VMware Installer...done.
Installing VMware Installer 3.0.0
Copying files...
...SNIP...
Configuring...
Installation was successful.

Introduction to VirtualBox

An excellent and free alternative to VMware Workstation is VirtualBox. With VirtualBox, hard disks are emulated in container files, called Virtual Disk Images (VDI). Aside from VDI format, VirtualBox can also handle hard disk files from VMware virtualization products (.vmdk), the Virtual Hard Disk format (.vhd), and others. We can also convert these external formats using the VBoxManager command-line tool that is part of VirtualBox. We can install VirtualBox from the command line or download the installation file from the official website and install it manually.

VirtualBox Installation

kalijester68@htb[/htb]$ sudo apt install virtualbox virtualbox-ext-pack -y

From the example of a created VM shown above, we can see what configuration options are available for the VDI within VirtualBox. Also, we have the possibility and function to encrypt the VM, which we should always use. We will use this option as soon as we have prepared our VM accordingly and ready for use.