ISC2 CC Network Security Practice Question
A security analyst notices a high volume of ICMP Echo Reply packets from an external server to an internal host that never sent Echo Requests. Which type of attack is likely occurring?
Answer choices
Why each option matters
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
Smurf attack
Unsolicited ICMP replies may indicate a DoS attack using reflected traffic.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✓
Smurf attack
Why this is correct
Smurf attack sends ICMP Echo Requests to a broadcast address with spoofed source, causing many replies to flood the victim.
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SYN flood
Why it's wrong here
SYN flood uses TCP SYN packets, not ICMP.
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ARP poisoning
Why it's wrong here
ARP poisoning manipulates ARP tables, not ICMP.
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DNS amplification
Why it's wrong here
DNS amplification uses DNS queries, not ICMP.
Go deeper
Related to this question
Learn chapter
Introduction to Security Principles
Key term
ICMP
ICMP is a network-layer protocol used by network devices to send error messages and operational information about network connectivity.
Key term
Denial-of-service
A Denial-of-service (DoS) attack is an attempt to make a computer, network, or online service unavailable to its intended users by overwhelming it with fake traffic or requests.
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JA
Written by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
This CC practice question is part of Courseiva's free ISC2 certification practice question bank. Courseiva provides original exam-style practice questions with explanations, topic-based practice, mock exams, readiness tracking, and study analytics to help learners prepare for the CC exam.