This CS0-003 practice question tests your understanding of security operations. Read the scenario carefully and evaluate each option against the stated constraints before committing to an answer. A key principle to apply: dGA detection often relies on statistical analysis of DNS queries.. 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 SOC analyst reviews DNS telemetry and sees a workstation resolving hundreds of algorithmically generated domains at fixed intervals, with most responses returning NXDOMAIN. What evidence should the analyst prioritize to validate command-and-control beaconing? In the root-cause analysis phase, Which finding would most directly explain the activity?
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
Correlate DNS query logs with endpoint process and network connection telemetry
Option C is correct because correlating DNS query logs with endpoint process and network connection telemetry provides direct evidence of command-and-control (C2) beaconing. The algorithmically generated domains (DGA) and NXDOMAIN responses are characteristic of malware that generates many domains to evade static blocklists, but only a few are actually registered by the attacker. By mapping the DNS queries to the specific process that initiated them (via endpoint telemetry) and the subsequent network connections (e.g., to the resolved IP of a successful DGA domain), the analyst can confirm C2 activity rather than just anomalous DNS traffic.
Key principle: DGA detection often relies on statistical analysis of DNS queries.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
✗
Block all DNS traffic from the subnet
Why it's wrong here
Immediate blanket blocking may disrupt operations and does not validate the source process.
✗
Search only for successful HTTP 200 responses
Why it's wrong here
DGA activity may fail resolution frequently, so HTTP status codes alone miss the behaviour.
✓
Correlate DNS query logs with endpoint process and network connection telemetry
Why this is correct
The pattern is suspicious, but process and connection context shows whether a host process is repeatedly attempting outbound C2 communication.
Related concept
DGA detection often relies on statistical analysis of DNS queries.
✗
Delete the host from the SIEM asset inventory
Why it's wrong here
Removing context makes investigation harder and does not contain the threat.
Common exam traps
Common exam trap: answer the scenario, not the keyword
The trap here is that candidates focus on the NXDOMAIN responses as a sign of failure and assume the activity is benign or that blocking DNS is the solution, rather than recognizing that the fixed-interval DGA pattern itself is the key indicator of C2 beaconing that requires cross-telemetry correlation.
Detailed technical explanation
How to think about this question
DGA-based malware, such as the Conficker or Gameover Zeus variants, uses a seed (e.g., current date) to generate hundreds of pseudo-random domains per day, attempting to resolve each until one returns a valid A record. The NXDOMAIN responses are expected for unregistered domains, but the fixed-interval query pattern (e.g., every 5 minutes) is a behavioral signature. Correlating with endpoint process telemetry (e.g., Sysmon Event ID 22 for DNS queries) and network connections (e.g., NetFlow to the resolved IP) allows the analyst to identify the malicious process and its C2 channel, even if the traffic is encrypted.
KKey Concepts to Remember
DGA detection often relies on statistical analysis of DNS queries.
Endpoint Detection and Response (EDR) provides process and network connection telemetry.
Correlation of disparate logs is fundamental to advanced threat hunting.
NXDOMAIN responses are common in DGA as many generated domains are unregistered.
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
DGA detection often relies on statistical analysis of DNS queries.
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 CS0-003 question in full detail.
Review dGA detection often relies on statistical analysis of DNS queries., then practise related CS0-003 questions on the same topic to reinforce the concept.
Security Operations — This question tests Security Operations — DGA detection often relies on statistical analysis of DNS queries..
What is the correct answer to this question?
The correct answer is: Correlate DNS query logs with endpoint process and network connection telemetry — Option C is correct because correlating DNS query logs with endpoint process and network connection telemetry provides direct evidence of command-and-control (C2) beaconing. The algorithmically generated domains (DGA) and NXDOMAIN responses are characteristic of malware that generates many domains to evade static blocklists, but only a few are actually registered by the attacker. By mapping the DNS queries to the specific process that initiated them (via endpoint telemetry) and the subsequent network connections (e.g., to the resolved IP of a successful DGA domain), the analyst can confirm C2 activity rather than just anomalous DNS traffic.
What should I do if I get this CS0-003 question wrong?
Review dGA detection often relies on statistical analysis of DNS queries., then practise related CS0-003 questions on the same topic to reinforce the concept.
What is the key concept behind this question?
DGA detection often relies on statistical analysis of DNS queries.
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