/etc/udev/rules.d/60-vboxdrv.rules
to contain (uncommented):
KERNEL=="vboxdrv", NAME="vboxdrv", OWNER="root", GROUP="root", MODE="0600"
#these lines below give access permission to vboxusers to properly work with usb nodes, but enabling them could be security risk (bnc#664520) !!
SUBSYSTEM=="usb_device", ACTION=="add", RUN+="VBoxCreateUSBNode.sh $major $minor $attr{bDeviceClass} vboxusers"
SUBSYSTEM=="usb", ACTION=="add", ENV{DEVTYPE}=="usb_device", RUN+="VBoxCreateUSBNode.sh $major $minor $attr{bDeviceClass} vboxusers"
SUBSYSTEM=="usb_device", ACTION=="remove", RUN+="VBoxCreateUSBNode.sh --remove $major $minor"
SUBSYSTEM=="usb", ACTION=="remove", ENV{DEVTYPE}=="usb_device", RUN+="VBoxCreateUSBNode.sh --remove $major $minor"
(careful: the lines have wrapped)