Quick Answer
The answer is a DNS amplification attack, which is the correct choice because it exploits open DNS resolvers to flood a target with large UDP responses sent to port 53, using a spoofed source IP that matches the victim’s address. This works by sending a small query with a spoofed source to many DNS servers, which then reply with much larger responses, amplifying the traffic volume dramatically. On the Certified Ethical Hacker CEH exam, this question tests your understanding of DDoS attack vectors and the abuse of UDP’s connectionless nature, often appearing in scenarios where you must distinguish amplification from reflection or simple flooding. A common trap is confusing it with a SYN flood, but remember that DNS amplification specifically relies on UDP, port 53, and the spoofed source IP of the target. For a memory tip, think “UDP 53 spoof = amplify the boom,” linking the protocol, port, and spoofed address to the traffic multiplication effect.
This CEH practice question tests your understanding of malware, social engineering and network attacks. Read the scenario carefully and evaluate each option against the stated constraints before committing to an answer. After answering, compare your reasoning against the explanation and wrong-answer breakdown below. Once you have made your selection, read the full explanation to reinforce the concept and understand why each distractor is designed to mislead on exam day.
A security team detects a large number of UDP packets from multiple sources directed at a single server's DNS port (53). The packets appear to have a spoofed source IP of the target. Which type of DDoS attack is being observed?
DNS amplification
Attackers send small queries with spoofed source IP to open DNS resolvers, which reply with large responses to the victim.
UDP flood
Why wrong: UDP flood directly floods target with UDP packets, but here the packets are from DNS resolvers and spoofed.
SYN flood
Why wrong: SYN flood uses TCP SYN packets, not UDP.
ICMP flood
Why wrong: ICMP flood uses ICMP echo requests, not UDP.
Answer choices
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
DNS amplification
A DNS amplification attack uses open DNS resolvers to send large responses to a spoofed victim IP, amplifying traffic. The characteristics include UDP, port 53, spoofed source, and many sources (amplifiers).
Key principle: Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
Answer analysis
For each option: why learners choose it and why it is or isn't the right answer here.
DNS amplification
Why this is correct
Attackers send small queries with spoofed source IP to open DNS resolvers, which reply with large responses to the victim.
Related concept
Read the scenario before looking for a memorised answer.
UDP flood
SYN flood
ICMP flood
Common exam traps
Many certification questions include familiar terms but test a specific constraint. Read the exact wording before choosing an answer that is generally true but wrong for this case.
Detailed technical explanation
This question should be treated as a scenario, not a definition check. Identify the problem, the constraint and the best action. Then compare each option against those facts.
Key takeaway
Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
Real-world example
A practitioner preparing for the CEH exam encounters this exact type of scenario on the job. The correct answer here is not the most general option — it is the best answer for the specific constraint described. Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option. Real exam questions reward reading the full scenario before eliminating options, because the constraint defines which answer fits.
What to study next
Identify which CEH exam domain this question belongs to, then review the specific concept being tested. Practise related questions in that domain and focus on understanding why each wrong answer is tempting — not just why the correct answer is right.
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FAQ
Malware, Social Engineering and Network Attacks — This question tests Malware, Social Engineering and Network Attacks — Read the scenario before looking for a memorised answer..
The correct answer is: DNS amplification — A DNS amplification attack uses open DNS resolvers to send large responses to a spoofed victim IP, amplifying traffic. The characteristics include UDP, port 53, spoofed source, and many sources (amplifiers).
Identify which CEH exam domain this question belongs to, then review the specific concept being tested. Practise related questions in that domain and focus on understanding why each wrong answer is tempting — not just why the correct answer is right.
Read the scenario before looking for a memorised answer.
About these practice questions
Courseiva creates original exam-style practice questions with explanations and wrong-answer analysis. It does not publish real exam questions, exam dumps, or protected exam content. Learn why practice questions differ from exam dumps →
Same concept, more angles
These questions test the same concept from different angles. Work through them to make sure you can recognise it however the exam phrases it.
Variation 1. An organization's security team observes a surge in outgoing DNS queries to external servers from a single internal host, with each query returning unusually large responses (e.g., 4000 bytes). The host is not configured as a DNS resolver. Which attack is MOST likely occurring?
hardWhy C: DNS amplification attack uses small queries to generate large responses, overwhelming the victim. The large response sizes and unusual outgoing queries from a single host indicate the host is being used as an amplifier in a DDoS attack.
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Last reviewed: Jun 21, 2026
This CEH practice question is part of Courseiva's free EC-Council 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 CEH exam.
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