You can then open virt-manager. To create a new virtual machine, you can go to File → New virtual machine or just click on the New button below the File menu entry, like so. The New VM window will appear. In my case, since my Debian “host” system was running as a VM, virt-manager was letting me know KVM was not available for me. Jan 08, 2021 The virt-manager application provides an easy-to-use interface that allows users to perform a wide range of tasks including creating guest machines and assigning critical virtual resources such as CPU, memory, and disk space. Users can also configure networking, pause, and resume the guest machines as well as monitor performance.

You may have already read our other articles, such as our Kali Linux VirtualBox Pentest Lab, which details how you can use Virtualbox to set up your own lab. This is great if you’re a Windows/Mac user, and either don’t have the money or don’t want to pay for VMware’s virtualization solutions. Many of us, Linux users, can and do benefit from running VirtualBox to practice our pentesting and hacking skills.

However, with the new developments for us Debian users, we are now instructed to use Virtual Machine Manager (virt-manager) instead. So, today we’re going to give you a full guide on how you can create your own penetration testing lab with KVM, using virt-manager as a graphical UI to manage all our virtual machines

KVM stands for Kernel Virtual Machine, and it’s a Linux kernel module that provides full hypervisor capabilities; meaning it allows your system to run virtual machines. The main difference is that, if you’re a Linux user, then it comes already bundled with the kernel. The only restriction is that your computer’s
processor should contain hardware virtualization extensions (Intel-VT or AMD-V) to run KVM.

If these virtualization extensions are not present on your CPU, you don’t need to worry. You can still benefit from using virt-manager to manage virtual machines. You will however, experience a performance hit on your system. This is relatively uncommon on modern systems, but it is important to notice, just in case. For example, testing on a laptop with a 2nd-generation Intel i5, it runs KVM perfectly. Meanwhile, another computer with a Core 2 Duo processor does not run KVM. It can, of course, run virt-manager, but the performance sadly isn’t the same as the one with the i5 CPU.

To check if your processor comes with hardware virtualization extensions, just type:

As you can see, on this computer, which has an AMD Phenom II processor, which comes with the AMD-V hardware extension enabled.

Now, since we’re on Debian, we’re going to need the qemu-kvm package, which is the KVM-ready version of the QEMU system emulator. For extra configuration convenience, we’re going to also install libvirt-daemon-system along with the virt-manager, which is a tool that
will help us manage all of our VMs from a Graphical User Interface (GUI).

Now that we have everything installed, we can download our virtual machines. We’re going to create our Virtual Machines. For this example, we will be downloading the latest Kali ISO image, along with the Metasploitable2 virtual machine.

Once downloaded, we need to open up a terminal in the directory where we just downloaded them.

Upon listing the contents, we can use the unzip command to extract the Metasploitable2 virtual machine’s files.

We are now ready to run virt-manager for the first time. Here, we should be asked to enter our password.

To skip having to re-enter your password again and again, you can add your user to the sudo group, the group name may vary depending on your distribution, but in Debian the group is called sudo. Also, you’ll need to become root. So, for user hl:

Upon which, we need to log out and log back in, so that our user is recognized as member of the sudo group.

You can then open virt-manager. To create a new virtual machine, you can go to File → New virtual machine or just click on the New button below the File menu entry, like so.

The New VM window will appear. In my case, since my Debian “host” system was running as a VM, virt-manager was letting me know KVM was not available for me. If I were running it on my actual host OS, this alert does not appear. Select the Import existing disk image option and press Forward.

Next, you’ll need to browse your system’s storage to select the disk image for the Metasploitable VM. Press Browse search for the storage volume.

The window that appears displays 2 sections. The left side shows the different storage pools from which you can select your image. The right side lists all storage volumes contained in the selected storage pool. Since the current default pool is empty, we can press Browse Local to open other directories to use as storage pools.

You will now need to locate the Metasploitable2.vmdk file we just extracted.

Virt-manager Efi

Next, we are required to select the operating system we’re installing. For demonstration purposes, I went with Generic. However, you can choose several of the major distros, just begin typing their name and the list should pop up, as seen here when I selected Generic:

Note: If you get a message saying the emulator may not have permissions for the path where the disc image is located, asking if you want to correct it, you’ll need to click on Yes to be able to continue. Press forward when ready.

We are now required to choose the Memory and CPU settings for the VM. To ensure we’re using the same settings from the OVA, do the following:

Open up a terminal
Navigate to the directory with the extracted contents of the OVA
Look at the .vmx file’s contents (e.g. using cat)

When looking into the contents of the file, pay close attention to the memsize and numvcpus values; as we’ll need to enter those into the Memory and CPU settings fields for the emulator. Press Forward afterwards.

On the final configuration stage, we’ll need to Name the new VM. We will name it Metasploitable2 and check the Customize configuration before install option.

If you expand the Network selection section below, you’ll be shown all different networking options available for this VM. For security purposes, mainly with Metasploitable, we’re going to use NAT. Once the network has been selected, press Finish.

If this is the very first time you use a VM, you’ll be notified that the current network is inactive. Press Yes to activate it.

If, after that, you get an error message like the one below, you will need to modify the Connection Details, as we will demonstrate in a bit.

However, just so we don’t need to re-create the virtual machine all over again, we can simply select a macvtap interface and bridge it to the Ethernet interface, and press Finish afterwards.

The next window will allow you to verify and customize the virtual machine’s configuration before it is installed. Feel free to check its setting and, when ready, press Begin Installation.

You’ll see a message notifying that Virtual Machine Manager wants to inhibit shortcuts. Feel free to allow it, and notice it says that you can restore them by pressing Shift+Escape.

The virtual machine will start, but it won’t have network access. So, once it’s loaded the OS, you’ll need to log in with user/password msfadmin / msfadmin and then enter the command sudo poweroff to power off the VM.

We can now go ahead and fix the connection settings to enable the NAT network for our virtual machines.

First, click the QEMU/KVM header on the Virtual Machine Manager window, and then go to Edit → Connection Details.

You’ll notice that, even though the network is set to b