The correct answer is exploit code for a buffer overflow. This Snort rule detects a buffer overflow attempt by matching a specific payload pattern, such as a long string of repeated characters or a shellcode signature, which is characteristic of exploit code designed to corrupt memory in a vulnerable service. On the Cisco CyberOps Associate 200-201 exam, this tests your ability to interpret Snort rule syntax and distinguish between protocol-level anomalies and exploit-specific payloads—a common trap is confusing the target protocol (like SMB) with the actual exploit signature. Remember, the rule’s content match targets the overflow payload itself, not the protocol header, so focus on the data pattern rather than the service name. Memory tip: “Payload pattern, not protocol—buffer overflows are about the data, not the door.”
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.
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
Exploit code for a buffer overflow
The Snort rule detects a buffer overflow attempt by matching a specific pattern (e.g., a long string of 'A' characters or a shellcode pattern) in the payload, which is characteristic of exploit code targeting a vulnerable service. Buffer overflow exploits often send oversized data to trigger memory corruption, and Snort rules use content matching and byte_test to identify such anomalies. This rule likely targets a known overflow in a protocol like SMB or RPC, but the signature is specific to the exploit payload, not the protocol itself.
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.
✗
A NetBIOS name service query
Why it's wrong here
Incorrect. NetBIOS uses different ports and payloads.
✗
A vulnerability in Microsoft RPC
Why it's wrong here
Incorrect. The rule detects exploit attempts, not the vulnerability itself.
✗
Normal SMB traffic
Why it's wrong here
Incorrect. Normal SMB traffic does not contain this pattern.
✓
Exploit code for a buffer overflow
Why this is correct
Correct. The null-byte pattern is indicative of a buffer overflow exploit.
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 protocol-specific signatures (e.g., 'this is SMB traffic') and exploit-specific signatures (e.g., 'this is a buffer overflow payload'), so the trap here is that candidates see 'SMB' in the rule and assume it's normal SMB traffic, missing the exploit pattern in the payload.
Detailed technical explanation
How to think about this question
Buffer overflow detection in Snort often relies on the 'content' keyword with a specific byte sequence (e.g., '|41 41 41 41|' for 'AAAA') and the 'within' or 'distance' modifiers to locate the overflow trigger. In real-world scenarios, such as the EternalBlue exploit (MS17-010), the rule would match the SMBv1 Trans2 request with a crafted 'SMB_COM_TRANSACTION2' packet containing a malformed 'DataCount' field. The subtlety is that the rule must differentiate between legitimate large packets and malicious ones by checking for specific offset values or size thresholds.
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 small business has 20 workstations on the 192.168.1.0/24 network and one public IP from its ISP. The router uses PAT (NAT overload) so all 20 devices share one public address using different source ports. NAT questions test whether you understand the four address terms and which direction each translation applies.
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: Exploit code for a buffer overflow — The Snort rule detects a buffer overflow attempt by matching a specific pattern (e.g., a long string of 'A' characters or a shellcode pattern) in the payload, which is characteristic of exploit code targeting a vulnerable service. Buffer overflow exploits often send oversized data to trigger memory corruption, and Snort rules use content matching and byte_test to identify such anomalies. This rule likely targets a known overflow in a protocol like SMB or RPC, but the signature is specific to the exploit payload, not the protocol itself.
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.
What is the key concept behind this question?
Read the scenario before looking for a memorised answer.
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Question Discussion
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