6.0.3

Table Of Contents
Disable Unnecessary Functions Inside Virtual Machines
Any service running in a virtual machine provides the potential for aack. By disabling unnecessary system
components that are not necessary to support the application or service running on the system, you reduce
the number of components that can be aacked.
Virtual machines do not usually require as many services or functions as physical servers. When you
virtualize a system, evaluate whether a particular service or function is necessary.
Procedure
n
Disable unused services in the operating system.
For example, if the system runs a le server, turn o any Web services.
n
Disconnect unused physical devices, such as CD/DVD drives, oppy drives, and USB adaptors.
n
Disable unused functionality, such as unused display features or HGFS (Host Guest File System).
n
Turn o screen savers.
n
Do not run the X Window system on Linux, BSD, or Solaris guest operating systems unless it is
necessary.
Remove Unnecessary Hardware Devices
Any enabled or connected device represents a potential aack channel. Users and processes without
privileges on a virtual machine can connect or disconnect hardware devices, such as network adapters and
CD-ROM drives. Aackers can use this capability to breach virtual machine security. Removing unnecessary
hardware devices can help prevent aacks.
An aacker with access to a virtual machine can connect a disconnected hardware device and access
sensitive information on the media left in the drive, or disconnect a network adapter to isolate the virtual
machine from its network, resulting in a denial of service.
n
Ensure that unauthorized devices are not connected and remove any unneeded or unused hardware
devices.
n
Disable unnecessary virtual devices from within a virtual machine.
n
Ensure that no device is connected to a virtual machine if it is not required. Serial and parallel ports are
rarely used for virtual machines in a data center, and CD/DVD drives are usually connected only
temporarily during software installation.
Procedure
1 Log into a vCenter Server system using the vSphere Web Client.
2 Right-click the virtual machine and click Edit .
3 Check each hardware device and ensure that you want it connected.
Include checks for the following devices:
n
Floppy drives
n
Serial ports
n
Parallel ports
n
USB controllers
n
CD-ROM drives
Chapter 7 Securing Virtual Machines
VMware, Inc. 221