Preventing Denial-of-Service Attacks in a Shared Cloud Environment

A.

Reservations ensure that a minimum level of resources will always be available to a cloud customer for them to start and operate their services.

In the event of a DoS attack against one customer, they can guarantee that the other customers will still be able to operate.

Denial-of-service (DoS) attacks are a type of cyber attack where the attacker seeks to disrupt the availability of a service by overwhelming it with a flood of traffic or other types of requests. In a cloud computing environment, where multiple customers share the same physical infrastructure, a DoS attack against one customer can potentially affect other customers as well.

To protect cloud customers from such attacks, various security measures can be employed. Among the options listed in the question, the most relevant ones are:

A. Reservations: A reservation is a type of service agreement where the customer pays for exclusive access to a specific amount of computing resources, such as CPU, memory, or storage. By reserving resources, the customer can ensure that they are available for their use when needed, regardless of the activities of other customers. In the context of a DoS attack, reservations can be useful for mitigating the impact of the attack on the targeted customer, as the reserved resources can be used to maintain the availability of critical services.

B. Measured service: Measured service refers to the practice of monitoring and reporting the usage of computing resources by customers. By measuring the consumption of resources, cloud providers can enforce policies that limit the usage of individual customers and prevent them from monopolizing the resources at the expense of others. In the context of a DoS attack, measured service can be useful for detecting anomalous traffic patterns and identifying the source of the attack.

C. Limits: Limits are policies that restrict the usage of resources by customers, either in absolute terms (e.g., maximum number of requests per second) or relative to other customers (e.g., percentage of total available resources). Limits can be enforced through technical means, such as network throttling or rate limiting, or through contractual means, such as service-level agreements (SLAs). In the context of a DoS attack, limits can be useful for containing the impact of the attack and preventing it from affecting other customers.

D. Shares: Shares refer to the allocation of resources among multiple customers based on predefined ratios or priorities. By assigning different levels of shares to different customers, cloud providers can ensure that critical services receive a higher priority than less important ones. In the context of a DoS attack, shares can be useful for dynamically adjusting the allocation of resources based on the changing demands of the customers and the severity of the attack.

In summary, all of the options listed in the question can be useful for protecting cloud customers from a DoS attack against another customer hosted in the same cloud. However, the most effective approach may depend on the specific circumstances of the attack and the nature of the services being offered.