Unix

The proprietary version of Oracle VirtualBox does offer USB support.
This means that the guest operating system can access USB devices plugged into the host system.

This USB passthrough feature is also available with many other desktop virtualization solutions, e.g. KVM and Qemu. Nevertheless it seems VirtualBox is favoured by a large number of users who are installing VirtualBox only to find that they cannot actually make their USB devices visible to the guest operating system. The common problem seems to be that they checkboxes next to the devices are grayed out, preventing the user from marking them to be added to the guest.

There are a large number of forum articles and blog posts available which all claim to have a solution to the issue. Very often the suggested solution is to change the mount options for /proc/bus/usb in fstab or add an appropriate entry. Sometimes it is suggested to mount usbdevfs to /sys/bus/usb/drivers. Some report success by editing certain udev rules so that files the in the procfs belong to the user executing the VirtualBox binary.

All these solutions have one thing in common:
They are all wrong!
The fact that they are mindlessly repeated by posters in a large number of user-centric web forums does not help at all.
It is still wrong!
I said it before but it still is true: Web forums are full of cargo-cult users: No idea what they are doing but trying and talking about it in the hope that it will achieve something.

The right solution is actually very simple. All that is needed is to add the user running VirtualBox to the vboxusers group:

[root@minos ~]# usermod -a -G vboxusers athienemann
[root@minos ~]# groups athienemann
athienemann : athienemann vboxusers
[root@minos ~]# 

That's all. The user athienemann now can add and remove USB devices from VirtualBox guests.
Wasn't that easy? No fiddling with udev or fstab needed.