Cloud computing refers to accessing computing resources via a different location than your local computer. In most scenarios, you’re accessing these resources through the Internet. If you’re planning to take the SY0-501 or SY0-401 Security+ exam, you should have a basic understanding of the cloud service models and the cloud deployment models.
For example, can you answer this question?
Q. The Shelbyville Nuclear Power Plant stores some data in the cloud using its own resources. The Springfield school system also has a cloud using its own resources. Later, the two organizations decide to share some of the educational data in both clouds. Which of the following BEST describes the cloud created by these two organizations?
A. Community
B. Private
C. Public
D. PaaS
More, do you know why the correct answer is correct and the incorrect answers are incorrect? The answer and explanation is available at the end of this post.
As an example, if you use web-based email such as Gmail, you’re using cloud computing. More specifically, the web-based mail is a Software as a Service cloud computing service. You know that you’re accessing your email via the Internet, but you really don’t know where the physical server hosting your account is located. It could be in a data center in the middle of Virginia, tucked away in Utah, or just about anywhere else in the world.
Security Responsibilities with Cloud Models
One important consideration with cloud service models is the difference in security responsibilities assigned to the cloud service provider (CSP) and the customer. The figure (derived from Figure 1 in the U.S. Department of Defense (DoD)“Cloud Computing Security Requirements Guide”) shows the difference in the amount of responsibilities for a SaaS, PaaS, and IaaS. This includes both maintenance responsibilities and security responsibilities.
Security responsibilities with cloud models
As an example, for SaaS, consider Gmail. Google has the primary responsibility for maintaining the app and ensuring it is available. Additionally, Google has the primary responsibility of ensuring the security for Gmail. If you use it, you still have some responsibility, such as ensuring you use a strong password that is different from other online accounts.
With a PaaS solution, the CSP has the responsibility to provide you with the platform and ensure it remains available. Many CSPs provide additional security protection, such as firewalls, malware content filters, and intrusion detection systems. Still, the customer has a much greater responsibility for the operation, configuration, and security of the platform.
The CSP has the least responsibility for an IaaS solution and the customer has the most responsibility when compared with both PaaS and SaaS.
Cloud Deployment Models
There are four categories of cloud deployment models: public, private, community, and hybrid. These identify who has access to the cloud infrastructure.
Public cloud services are available from third-party companies, such as Amazon, Google, Microsoft, and Apple. They provide similar services to anyone willing to pay for them.
A private cloud is set up for specific organizations. For example, the Shelbyville Nuclear Power Plant might decide it wants to store data in the cloud, but does not want to use a third- party vendor. Instead, the plant chooses to host its own servers and make these servers available to internal employees through the Internet.
Communities with shared concerns (such as goals, security requirements, or compliance considerations) can share cloud resources within a community cloud. As an example, imagine that the Shelbyville Nuclear Power Plant and several schools within Springfield decided to share educational resources within a cloud. They could each provide resources for the cloud and only organizations within the community would have access to the resources.
Not all cloud implementations fit exactly into these definitions, though. A hybrid cloud is a combination of two or more clouds. They can be private, public, community, or a combination. These retain separate identities to help protect resources in private clouds. However, they are bridged together, often in such a way that it is transparent to the users.
Remember this
A cloud access security broker (CASB) is a software tool or service deployed between an organization’s network and the cloud provider. It provides Security as a Service by monitoring traffic and enforcing security policies. Private clouds are only available for one organization. Public cloud services are provided by third-party companies and available to anyone. A community cloud is shared by multiple organizations. A hybrid cloud is a combination of two or more clouds.
Q. The Shelbyville Nuclear Power Plant stores some data in the cloud using its own resources. The Springfield school system also has a cloud using its own resources. Later, the two organizations decide to share some of the educational data in both clouds. Which of the following BEST describes the cloud created by these two organizations?
A. Community
B. Private
C. Public
D. PaaS
Answer is A. They created a community cloud. In the scenario, the two organizations have a common goal of sharing educational materials.
The individual clouds created by each organization are private clouds, but the resources in the shared community cloud are not private.
A public cloud would be available to anyone, but these are restricted. Platform as a Service (PaaS) provides an easy-to-configure operating system and on-demand computing for customers, but is unrelated to this question.
See Chapter 5 of the CompTIA Security+: Get Certified Get Ahead: SY0-501 Study Guide
or
Chapter 5 of the CompTIA Security+: Get Certified Get Ahead: SY0-401 Study Guide
for more information on securing hosts and data.