It took me many hours to get USB working, so I summarize how I solved it.
Followed instructions of this forum:
1) Use VirtualBox PUEL edition
2) Remove usbfs entry from fstab
3) Change /etc/udev/rules.d/10-vboxdrv.rules to:
=>
KERNEL=="vboxdrv", NAME="vboxdrv", OWNER="root", GROUP="root", MODE="0600"
SUBSYSTEM=="usb_device", GROUP="vboxusers", MODE="0664"
SUBSYSTEM=="usb", ENV{DEVTYPE}=="usb_device", NAME="VirtualBox/$env{BUSNUM}/$env{DEVNUM}", GROUP="vboxusers", MODE="0664"
=>
The only thing missing in this list is:
4) Add empty filter to USB device setting.
In case guest is running in seamless mode, click Hostkey + L to go to normal mode.
Insert USB stick and an icon is visible in the right bottom corner for the USB device.