How does a denial-of-service attack work?

A Denial-of-Service (DoS) attack is an explicit attempt by an attacker to make a machine or network resource unavailable to its intended users. The primary goal is to disrupt the "availability" aspect of the CIA (Confidentiality, Integrity, Availability) triad. This is typically accomplished by flooding the targeted machine or resource with superfluous requests in an attempt to overload systems and prevent some or all legitimate requests from being fulfilled.

B. This describes a brute-force or dictionary attack, which is a method used to crack passwords and compromise authentication, not deny service.

C. This describes a password cracking attempt. While a poorly configured system might crash under such an attack, the primary goal is to compromise credentials, not cause a denial of service.

D. This describes impersonation, spoofing, or social engineering attacks, where the objective is to deceive a system or user to gain unauthorized access, not to disrupt availability.

1. National Institute of Standards and Technology (NIST). (2020). NIST Special Publication 800-61 Rev. 2

Computer Security Incident Handling Guide. U.S. Department of Commerce. In Section 2.3.3

"Denial of Service

" it is defined as an attack that "prevents or impairs the normal authorized use of networks

systems

or applications by exhausting resources." This directly supports the concept of preventing legitimate users from accessing a service. (Page 11).

2. Kurose

J. F.

& Ross

K. W. (2017). Computer Networking: A Top-Down Approach (7th ed.). Pearson. In Chapter 8

"Security in Computer Networks

" a DoS attack is defined as an attack that renders a network

host

or other piece of infrastructure unusable by legitimate users. (Section 8.7.1

"Denial of Service (DoS) Attacks").

3. Saltzer

J. H.

& Kaashoek

M. F. (2009). Principles of Computer System Design: An Introduction. Morgan Kaufmann. MIT OCW 6.033 Computer System Engineering

Spring 2009. In Chapter 11

"Security and Protection

" DoS attacks are described as actions that "prevent legitimate principals from using a service." (Section 11.6.3

"Denial of Service").