How does a denial-of-service (DoS) attack work?

Comprehensive and Detailed Explanation:

A Denial-of-Service (DoS) attack aims to overwhelm a system or service with excessive requests, rendering it unavailable to legitimate users. It targets:

Bandwidth (e.g., flooding with traffic)

Resources (CPU, memory, or disk usage)

Applications (exploiting bugs that crash services)

From CEH v13 Courseware:

Module 9: Denial-of-Service Attacks

Incorrect Options:

B refers to brute-force attacks.

C mischaracterizes password cracking.

D describes impersonation or spoofing, not DoS.