The answer is a SYN flood attack. This is correct because the packet capture would reveal an overwhelming number of SYN packets sent to the target, often with spoofed source IP addresses, while the corresponding SYN-ACK and ACK packets are absent or minimal, indicating that the three-way handshake is never completed. This forces the target server to allocate resources for half-open connections, eventually exhausting its backlog queue and denying service to legitimate traffic. On the Cisco CyberOps Associate 200-201 exam, this scenario tests your ability to distinguish a SYN flood from other DoS attacks like a UDP flood or ICMP flood by focusing on the TCP handshake imbalance. A common trap is mistaking a high volume of traffic for a bandwidth-based attack, but the key is the specific pattern of incomplete handshakes. To remember, think of the mnemonic “SYN sent, never spent”—the server spends resources on connections that never finish.
200-201 Network Intrusion Analysis Practice Question
This 200-201 practice question tests your understanding of network intrusion analysis. 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.
Exhibit
Refer to the exhibit.
Event: 02/15/2023 14:32:10
Src IP: 10.10.10.50
Dst IP: 203.0.113.5
Protocol: TCP
Flags: SYN
Length: 60 bytes
(Repeated 100 times in the last 2 seconds)
Based on the exhibit, what is the most likely type of attack being observed?
Clue words in this question
Noticing these words before you look at the options changes how you read each choice.
Clue: "most likely"
Why it matters: Probability qualifier — the question wants the most probable cause or outcome, not a guaranteed one. Eliminate low-probability options.
Refer to the exhibit.
Event: 02/15/2023 14:32:10
Src IP: 10.10.10.50
Dst IP: 203.0.113.5
Protocol: TCP
Flags: SYN
Length: 60 bytes
(Repeated 100 times in the last 2 seconds)
A
ARP spoofing
Why wrong: ARP spoofing involves ARP replies, not TCP SYN.
B
DNS amplification attack
Why wrong: DNS amplification uses UDP, not TCP SYN.
C
Port scan
Why wrong: Port scans target multiple ports, not repeated SYN to same host.
D
SYN flood
Rapid SYN packets without completing handshake indicates SYN flood.
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
SYN flood
A SYN flood attack exploits the TCP three-way handshake by sending a high volume of SYN packets with spoofed source IP addresses, causing the target to allocate resources for half-open connections until it exhausts its backlog queue and denies legitimate traffic. The exhibit likely shows a massive spike in SYN packets without corresponding SYN-ACK or ACK completions, which is the hallmark of this attack.
Key principle: Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
Port scans target multiple ports, not repeated SYN to same host.
✓
SYN flood
Why this is correct
Rapid SYN packets without completing handshake indicates SYN flood.
Clue confirmation
The clue word "most likely" in the question point toward this answer.
Related concept
Read the scenario before looking for a memorised answer.
Common exam traps
Common exam trap: answer the scenario, not the keyword
Cisco often tests the distinction between a SYN flood (which targets the TCP handshake state table) and a port scan (which probes for open ports), so the trap here is that candidates see many SYN packets and assume it's a port scan rather than recognizing the volumetric nature of the attack.
Detailed technical explanation
How to think about this question
In a SYN flood, the attacker sends SYN packets with random source IPs, and the target responds with SYN-ACKs to those unreachable IPs, leaving the connection in a half-open state (SYN_RCVD) until a timeout (typically 30-60 seconds per RFC 793). Modern defenses like SYN cookies (RFC 4987) mitigate this by encoding connection state in the SYN-ACK sequence number, avoiding resource allocation until the final ACK is received.
KKey Concepts to Remember
Read the scenario before looking for a memorised answer.
Find the constraint that changes the correct option.
Eliminate answers that are true in general but not in this case.
TExam Day Tips
→Watch for words such as best, first, most likely and least administrative effort.
→Review why wrong options are wrong, not only why the correct option is correct.
Key takeaway
Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
Real-world example
How this comes up in practice
A practitioner preparing for the 200-201 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
Got this wrong? Here's your next step.
Identify which exam domain this question belongs to, review the core concept, then practise similar questions from the same domain.
Network Intrusion Analysis — This question tests Network Intrusion Analysis — Read the scenario before looking for a memorised answer..
What is the correct answer to this question?
The correct answer is: SYN flood — A SYN flood attack exploits the TCP three-way handshake by sending a high volume of SYN packets with spoofed source IP addresses, causing the target to allocate resources for half-open connections until it exhausts its backlog queue and denies legitimate traffic. The exhibit likely shows a massive spike in SYN packets without corresponding SYN-ACK or ACK completions, which is the hallmark of this attack.
What should I do if I get this 200-201 question wrong?
Identify which exam domain this question belongs to, review the core concept, then practise similar questions from the same domain.
Are there clue words in this question I should notice?
Yes — watch for: "most likely". Probability qualifier — the question wants the most probable cause or outcome, not a guaranteed one. Eliminate low-probability options.
What is the key concept behind this question?
Read the scenario before looking for a memorised answer.
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