6.5.1

Table Of Contents
4 In each resource pool, leave Shares set to the default to ensure that each virtual machine in the pool
receives approximately the same resource priority.
With this setting, a single virtual machine cannot use more than other virtual machines in the resource
pool.
What to do next
See the vSphere Resource Management documentation for information about shares and limits.
Disable Unnecessary Functions Inside Virtual Machines
Any service that is running in a virtual machine provides the potential for attack. By disabling system
components that are not necessary to support the application or service that is running on the system,
you reduce the potential.
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 file server, turn off any Web services.
n
Disconnect unused physical devices, such as CD/DVD drives, floppy drives, and USB adapters.
n
Disable unused functionality, such as unused display features or HGFS (Host Guest File System).
n
Turn off screen savers.
n
Do not run the X Window system on top of Linux, BSD, or Solaris guest operating systems unless it is
necessary.
Remove Unnecessary Hardware Devices
Any enabled or connected device represents a potential attack channel. Users and processes with
privileges on a virtual machine can connect or disconnect hardware devices, such as network adapters
and CD-ROM drives. Attackers can use this capability to breach virtual machine security. Removing
unnecessary hardware devices can help prevent attacks.
An attacker with access to a virtual machine can connect a disconnected hardware device and access
sensitive information on media that is left in a hardware device. The attacker can potentially disconnect a
network adapter to isolate the virtual machine from its network, resulting in a denial of service.
n
Do not connect unauthorized devices to the virtual machine.
n
Remove unneeded or unused hardware devices.
n
Disable unnecessary virtual devices from within a virtual machine.
n
Ensure that only required devices are connected to a virtual machine. Virtual machines rarely use
serial or parallel ports. As a rule, CD/DVD drives are connected only temporarily during software
installation.
vSphere Security
VMware, Inc. 134