The correct answer is to baseline the normal traffic patterns during peak business hours. This is because a NIDS, particularly one using anomaly-based detection, must first establish a statistical model of what constitutes legitimate activity on the network; without this reference, the system cannot distinguish between a genuine threat and a routine surge in traffic, leading directly to false positives. On the ISC2 Certified in Cybersecurity CC exam, this concept tests your understanding of how to reduce noise in detection systems—a common trap is to choose baselining during off-peak hours, which would miss the high-volume patterns that trigger most false alarms. Remember that a baseline must capture the busiest, most variable periods to be effective. A useful memory tip is “Peak for Peace”: baseline during peak hours to keep false positives from peaking.
ISC2 CC Network Security Practice Question
This CC practice question tests your understanding of network security. Match the stated requirement to the specific cloud service, access model, or configuration option — many options are valid in isolation but not for this scenario. 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 engineer is configuring a network intrusion detection system (NIDS) to monitor traffic on a critical subnet. To minimize false positives, which of the following should the engineer baseline first?
Clue words in this question
Noticing these words before you look at the options changes how you read each choice.
Clue: "first"
Why it matters: Order matters here. You are being tested on which action comes before the others — not which action is generally useful.
Clue: "minimum / minimize"
Why it matters: Asks for the least resource use — fewest addresses, smallest subnet, lowest overhead. Eliminate over-provisioned options even if they would technically work.
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
The normal traffic patterns during peak business hours
Baselining normal traffic patterns during peak business hours establishes a reference of legitimate network behavior, which is essential for a NIDS to distinguish benign anomalies from actual threats. Without this baseline, the NIDS may generate false positives by flagging legitimate peak-hour traffic spikes as malicious. This aligns with the principle that anomaly-based detection relies on a statistical model of normal activity to reduce noise.
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.
✗
The results of a recent vulnerability scan
Why it's wrong here
Vulnerability scans identify weaknesses, not traffic patterns.
✓
The normal traffic patterns during peak business hours
Why this is correct
Baseline normal traffic to identify anomalies.
Clue confirmation
The clue words "first", "minimum / minimize" in the question point toward this answer.
Related concept
Read the scenario before looking for a memorised answer.
✗
The latest attack signatures from the vendor
Why it's wrong here
Signatures detect known attacks but don't establish a baseline.
✗
The firewall logs from the past 24 hours
Why it's wrong here
Firewall logs show blocked traffic, not necessarily normal patterns.
Common exam traps
Common exam trap: answer the scenario, not the keyword
ISC2 often tests the distinction between anomaly-based and signature-based detection, and the trap here is that candidates mistakenly think vulnerability scans or firewall logs provide a sufficient baseline, when in fact only observed normal traffic patterns during representative periods (like peak hours) can minimize false positives in an anomaly-based NIDS.
Trap categories for this question
Command / output trap
Firewall logs show blocked traffic, not necessarily normal patterns.
Detailed technical explanation
How to think about this question
Anomaly-based NIDS, such as those using statistical profiling or machine learning, require a baseline of normal traffic metrics like bandwidth utilization, packet rates, and protocol distributions (e.g., TCP SYN rates, DNS query frequencies). For example, a sudden 300% increase in HTTP requests during a flash sale could be flagged as a DDoS attack if the baseline only includes off-peak hours, but with a peak-hour baseline, the NIDS can correlate the spike with legitimate business activity. Real-world deployments often use a sliding window of 7–30 days of traffic data to account for weekly and seasonal variations.
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 security team runs a vulnerability scan on a web application and discovers an unpatched SQL injection flaw. The team prioritises remediation by CVSS score — critical flaws are patched within 24 hours, high within 7 days. Questions like this test whether you understand vulnerability management processes, scanning tools, and remediation prioritisation.
Related glossary terms
Concepts from this question explained
These glossary pages explain the core terms tested in this CC question in full detail.
Network Security — This question tests Network Security — Read the scenario before looking for a memorised answer..
What is the correct answer to this question?
The correct answer is: The normal traffic patterns during peak business hours — Baselining normal traffic patterns during peak business hours establishes a reference of legitimate network behavior, which is essential for a NIDS to distinguish benign anomalies from actual threats. Without this baseline, the NIDS may generate false positives by flagging legitimate peak-hour traffic spikes as malicious. This aligns with the principle that anomaly-based detection relies on a statistical model of normal activity to reduce noise.
What should I do if I get this CC 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: "first", "minimum / minimize". Order matters here. You are being tested on which action comes before the others — not which action is generally useful.
What is the key concept behind this question?
Read the scenario before looking for a memorised answer.
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