Unused hardware is enabled in virtual machines.

Virtual machines can connect or disconnect hardware devices. These devices may be network adapters, CD-ROM drives, USB drives, etc. Attackers may use this capability via non-privileged users or processes to breach virtual machines in several ways. An attacker that has access to a virtual machine may connect a CD-ROM drive and access sensitive information on the media left in the drive. Another action an attacker may perform is disconnecting the network adapter to isolate the virtual machine from its network resulting in a DoS. Therefore, as a general security precaution, SAs will remove any unneeded or unused hardware devices. If permanently removing a device is not feasible, SAs can restrict a virtual machine process or user from connecting or disconnecting devices from within the guest operating system.