The answer is DNS query logs from internal DNS servers, as they represent the least critical logs for SIEM archiving when storage is constrained. This is because DNS query logs are high-volume, low-signal data primarily containing routine name resolution requests, which are not essential for real-time alerting or immediate incident response, unlike firewall denies, IDS alerts, or authentication failures. On the ISC2 Certified in Cybersecurity CC exam, this scenario tests your understanding of log prioritization and data retention policies, often appearing as a practical question about balancing security monitoring with storage limits. A common trap is assuming all logs are equally critical, but the key is recognizing that DNS queries, while useful for forensic analysis of C2 traffic, are less actionable for ongoing security operations. Remember the memory tip: DNS stands for “Do Not Store first” when space is tight.
ISC2 CC Security Operations Practice Question
This CC practice question tests your understanding of security operations. 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.
An organization's security policy requires that all network traffic logs be retained for at least one year. The SIEM system is running low on storage, and the administrator must decide which data to archive first. Which data set is the least critical for ongoing security monitoring and can be archived earliest?
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: "least"
Why it matters: You want the option with minimum overhead, fewest steps, or lowest impact — not the most feature-rich or comprehensive answer.
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
DNS query logs from internal DNS servers
DNS query logs from internal DNS servers are the least critical for ongoing security monitoring because they primarily contain name resolution requests, which are high-volume and low-signal data. While they can be useful for threat hunting or forensic analysis of malware command-and-control (C2) traffic, they are not essential for real-time alerting or immediate incident response. Archiving them first preserves storage for more actionable logs like IDS alerts, firewall denies, and authentication failures.
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.
✗
Intrusion detection system alerts
Why it's wrong here
IDS alerts are high-priority for security monitoring and should be retained for analysis.
✓
DNS query logs from internal DNS servers
Why this is correct
DNS logs are less frequently used for real-time security monitoring and can be archived with lower priority.
Clue confirmation
The clue words "first", "least" in the question point toward this answer.
Related concept
Read the scenario before looking for a memorised answer.
✗
Firewall deny logs
Why it's wrong here
Firewall deny logs are essential for identifying scanning and attack attempts.
✗
Authentication logs from domain controllers
Why it's wrong here
Authentication logs are critical for detecting unauthorized access and must be retained for immediate analysis.
Common exam traps
Common exam trap: answer the scenario, not the keyword
ISC2 often tests the misconception that DNS logs are critical for security monitoring because they can reveal C2 traffic, but the trap is that they are high-volume, low-signal data best suited for archival after more immediate security event sources are preserved.
Detailed technical explanation
How to think about this question
DNS query logs typically contain fields like timestamp, source IP, queried domain, and response code. Under the hood, a single compromised host can generate thousands of DNS queries per hour to random domains (DGA), making raw logs noisy but valuable for post-compromise analysis. In a real-world scenario, a SOC might retain DNS logs for 30–90 days for threat hunting, while keeping IDS and firewall deny logs for the full year due to their direct security relevance.
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 SOC analyst notices unusual lateral movement in the network at 2 AM. The IR playbook dictates: identify and contain (isolate the affected machine), then eradicate (remove the malware), then recover (restore from backup), then document. Skipping containment before eradication risks the attacker regaining access. Questions like this test the sequence and rationale of incident response phases.
Related glossary terms
Concepts from this question explained
These glossary pages explain the core terms tested in this CC question in full detail.
Security Operations — This question tests Security Operations — Read the scenario before looking for a memorised answer..
What is the correct answer to this question?
The correct answer is: DNS query logs from internal DNS servers — DNS query logs from internal DNS servers are the least critical for ongoing security monitoring because they primarily contain name resolution requests, which are high-volume and low-signal data. While they can be useful for threat hunting or forensic analysis of malware command-and-control (C2) traffic, they are not essential for real-time alerting or immediate incident response. Archiving them first preserves storage for more actionable logs like IDS alerts, firewall denies, and authentication failures.
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", "least". 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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