Which of the following is a characteristic of a denial-of-service (DoS) attack?

A denial-of-service (DoS) attack is a cyber-attack in which the perpetrator seeks to make a machine or network resource unavailable to its intended users. The defining characteristic of a DoS attack is the disruption of services. This is most commonly accomplished by flooding the targeted host or network with superfluous requests in an attempt to overload the system's resources, such as CPU, memory, or network bandwidth. When the system is overwhelmed, it cannot process legitimate requests, effectively denying service to legitimate users.

A. This describes an unauthorized access attack, where the goal is to compromise a system's confidentiality, not its availability.

B. This describes a data breach or data integrity attack, which focuses on stealing or modifying information, not disrupting service access.

D. This describes a man-in-the-middle (MitM) attack, where an attacker secretly relays and possibly alters the communications between two parties.

1. Cisco. (n.d.). What Is a Denial-of-Service (DoS) Attack? Cisco.com. Retrieved from https://www.cisco.com/c/en/us/products/security/what-is-a-denial-of-service-attack-dos.html.

Reference Specifics: In the "How a DoS attack works" section, paragraph 1 states, "DoS attacks accomplish this by flooding the target with traffic, or sending it information that triggers a crash."

2. Cisco Networking Academy. (2020). CCNAv7: Enterprise Networking, Security, and Automation (ENSA) Curriculum.

Reference Specifics: Module 10, Section 10.1.2, "Threat Actors," describes DoS attacks as a common threat that results in an "interruption of network services to users, devices, or applications" by "overwhelming the target with a large amount of traffic."

3. Rivest, R. L. (2017). 6.857 Computer and Network Security, Lecture 15: Network Security II. MIT OpenCourseWare.

Reference Specifics: The lecture notes define Denial of Service (DoS) as an attack that "prevents legitimate users from using a service" and lists "flooding the server with requests" as a primary method.