GNU/Linux VirtualBox VM Enabling USB Guide
How to Attach USB Device on VirtualBox Virtual Machine on GNU/Linux desktop – Step by step Tutorial.
And to Enable USB on VirtualBox you need to Setup the complemental Package VirtualBox Extension Pack.
The Extension Pack has a different License (closed-source) and adds certain features, for instance USB2/USB3 support and support for RDP.

1. Installing VirtualBox Extension Pack
How to Install VirtualBox Extension Pack on Linux
VirtualBox Extension Pack Linux Setup Guide2. Setting up User Group
Now to Add User to Group
Simply play:sudo usermod -a -G vboxusers $USER
Then Reboot with:sudo reboot
After to check that you are in the vboxusers group:groups $USER
3. Enabling USB Device
Now to Attach USB Device
Access the Settings: