What is a "denial-of-service (DoS)" attack?

2025

What is a "denial-of-service (DoS)" attack?

  1. A.

    An attack that intercepts communication between two parties

  2. B.

    An attack that exploits vulnerabilities in software to gain unauthorized access

  3. C.

    An attack that floods a network with traffic to disrupt services

  4. D.

    An attack that uses malicious emails to trick users into revealing sensitive information

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Correct answer: C

Correct answer: An attack that floods a network with traffic to disrupt services.

Explanation: A denial-of-service (DoS) attack aims to overwhelm a system, application, or network with excessive traffic or requests so that legitimate users cannot access the service.

  • How it works: the attacker sends large volumes of traffic or resource-consuming requests (examples include SYN floods or UDP floods) to exhaust capacity.

  • Distributed attacks: when the traffic comes from many compromised devices it is called a distributed denial-of-service (DDoS) attack, which is harder to block.

  • Common mitigations: rate limiting, traffic filtering, using content delivery networks (CDNs) and dedicated DDoS protection services.

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