A VBOX-EXTPACK contains an extension pack used by Oracle VM VirtualBox, a virtualization program for running guest operating systems. It contains data that extends the base functionality of the software, which may include VirtualBox Remote Desktop Protocol (VRDP) support, virtual USB 2.0 and 3.0 devices, host webcam passthrough, and Intel PXE boot ROM.

To install the extension pack into VirtualBox, open Oracle VM VirtualBox Manager (VirtualBox needs to be closed) and follow these directions: Select File → Preferences. Click "Extensions" and select the "Add package" icon. Select the VBOX-EXTPACK file, click Install, then select "I agree." To view the currently installed extension packs in Oracle VM VirtualBox, go to the program preferences window and then navigate to the "Extensions" tab.