1. Edit your /etc/rc.sysinit file, change line no 26 from

   mount -n -t usbfs /proc/bus/usb /proc/bus/usb

   to

   mount -t usbfs -o remount,devgid=$(awk -F: '/^vboxusers:/{print $3}' /etc/gr    oup),devmode=664 /proc/bus/usb /proc/bus/usb

   So, your /etc/rc.sysinit should change from:

    23 if [ ! -d /proc/bus/usb ]; then
    24         modprobe usbcore >/dev/null 2>&1 && mount -n -t usbfs /proc/bus/usb     /proc/bus/usb
    25 else
    26        mount -n -t usbfs /proc/bus/usb /proc/bus/usb
    27 fi

   to

    24         modprobe usbcore >/dev/null 2>&1 && mount -n -t usbfs /proc/bus/usb     /proc/bus/usb
    25 else
    26 #       mount -n -t usbfs /proc/bus/usb /proc/bus/usb
    27 mount -t usbfs -o remount,devgid=$(awk -F: '/^vboxusers:/{print $3}' /etc/gr    oup),devmode=664 /proc/bus/usb /proc/bus/usb
    28 fi

2. Next, edit your /etc/udev/rules.d/10-vboxdrv.rules. Change line number 1 from

   KERNEL=="vboxdrv", NAME="vboxdrv", OWNER="root", GROUP="root", MODE="0600"

   to

   KERNEL=="vboxdrv", NAME="vboxdrv", OWNER="root", GROUP="root", MODE="0660"

3. Reboot your machine. You should now be able to mount you usb devices.

The following screenshot shows some of the USB devices can allow my guest machine to view.

The USB devices available for VirtualBox Guests

Devices like my USB Flash Drive are still blurred out. In order to get them to work, I need to install the VirtualBox Guest Additions first.

Source:

VirtualBox Community Forum