2 cissp ® Official Study Guide Eighth Edition

Virtual Software
A 
virtual application
is a software product deployed in such a way that it is fooled into 
believing it is interacting with a full host OS. A virtual (or virtualized) application has been 
packaged or encapsulated to make it portable and able to operate without the full instal-
lation of its original host OS. A virtual application has enough of the original host OS 
included in its encapsulation bubble (technically called a virtual machine, or VM) that it 
operates/functions as if it were traditionally installed. Some forms of virtual applications 
are used as portable apps (short for applications) on USB drives. Other virtual applications 
are designed to be executed on alternative host OS platforms—for example, running a 
Windows application within a Linux OS.
The term 
virtual desktop
refers to at least three different types of technology:
■
A remote access tool that grants the user access to a distant computer system by allow-
ing remote viewing and control of the distant desktop’s display, keyboard, mouse, and 
so on.
■
An extension of the virtual application concept encapsulating multiple applications 
and some form of “desktop” or shell for portability or cross-OS operation. This 
technology offers some of the features/benefits/applications of one platform to users 
of another without the need for multiple computers, dual-booting, or virtualizing an 
entire OS platform.
■
An extended or expanded desktop larger than the display being used allows the user 
to employ multiple application layouts, switching between them using keystrokes or 
mouse movements.

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Chapter 12 
■
Secure Communications and Network Attacks
See Chapter 8, “Principles of Security Models, Design, and Capabilities,” and Chapter 9, 
“Security Vulnerabilities, Threats, and Countermeasures,” for more information on virtu-
alization as part of security architecture and design.