2 cissp ® Official Study Guide Eighth Edition

Cloud-Based Systems and Cloud Computing
Cloud computing
is the popular term referring to a concept of computing where process-
ing and storage are performed elsewhere over a network connection rather than locally. 
Cloud computing is often thought of as Internet-based computing or remote virtualization. 
Ultimately, processing and storage still occurs on computers somewhere, but the distinction 
is that the local operator no longer needs to have that capacity or capability locally. This 
also allows a larger group of users to leverage cloud resources on demand. From the end-
user perspective, all the work of computing is now performed “in the cloud” and thus the 
complexity is isolated from them.
Cloud computing is a natural extension and evolution of virtualization, the internet, dis-
tributed architecture, and the need for ubiquitous access to data and resources. However, 
it does have some issues, including privacy concerns, regulation compliance difficulties, use 
of open- versus closed-source solutions, adoption of open standards, and whether or not 
cloud-based data is actually secured (or even securable). The 
hypervisor
, also known as the 
virtual machine monitor (VMM)
, is the component of virtualization that creates, manages, 
and operates the virtual machines. The computer running the hypervisor is known as the 
host OS, and the OSs running within a hypervisor-supported virtual machine are known as 
guest OSs.
A 
type I hypervisor
is a native or bare-metal hypervisor. In this configuration, there is 
no host OS; instead, the hypervisor installs directly onto the hardware where the host OS 
would normally reside. Type 1 hypervisors are often used to support server virtualization. 
This allows for maximization of the hardware resources while eliminating any risks or 
resource reduction caused by a host OS.
A 
type II hypervisor
is a hosted hypervisor. In this configuration, a standard regular OS 
is present on the hardware, and then the hypervisor is installed as another software applica-
tion. Type II hypervisors are often used in relation to desktop deployments, where the guest 
OSs offer safe sandbox areas to test new code, allow the execution of legacy applications, 
support apps from alternate OSs, and provide the user with access to the capabilities of a 
host OS.
Cloud storage
is the idea of using storage capacity provided by a cloud vendor as a 
means to host data files for an organization. Cloud storage can be used as form of backup 
or support for online data services. Cloud storage may be cost effective, but it is not 
always high speed or low latency. Most do not yet consider cloud storage as a replacement 
for physical backup media solutions but rather as a supplement for organizational data 
protection. Additionally, using cloud storage may involve additional risk because your 
organization’s data is residing on equipment in another facility and under third-party 
control.

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Chapter 9 
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Security Vulnerabilities, Threats, and Countermeasures
Elasticity
refers to the flexibility of virtualization and cloud solutions to expand or con-
tract based on need. In relation to virtualization, 
host elasticity
means additional hardware 
hosts can be booted when needed and then used to distribute the workload of the virtual-
ized services over the newly available capacity. As the workload becomes smaller, you can 
pull virtualized services off unneeded hardware so it can be shut down to conserve electric-
ity and reduce heat.
Some of the concepts in cloud computing are listed here: