VirtualBox 4 USB support in Linux

Download VirtualBox Oracle VM VirtualBox Extension Pack and install it by VirtualBox → File → Preferences... → Extensions → Add package.

Then grant vboxusers groups access to the USB device filesystem:

$ grep 108 /etc/group
vboxusers:x:108:
$ vim /etc/fstab
usbfs  /proc/bus/usb  usbfs  auto,busgid=108,busmode=0775,devgid=108,devmode=0664  0  0