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: network isolation severs C2 without losing volatile data.. 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 endpoint is actively beaconing to a known malicious IP and spawning credential-dumping tools. The business owner wants evidence preserved. What is the BEST containment action? In the root-cause analysis phase, Which finding would most directly explain the activity?
Clue words in this question
Noticing these words before you look at the options changes how you read each choice.
Clue: "best"
Why it matters: Signals that multiple options may be partially correct. Choose the option that most directly solves the exact problem described, not the one that sounds most complete.
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
Network-isolate the endpoint through EDR while preserving disk and memory evidence
Network-isolating the endpoint through EDR (option B) is the best containment action because it immediately stops the beaconing to the malicious IP and prevents further credential dumping while preserving both disk and memory evidence for forensic analysis. This aligns with incident response best practices where containment must not destroy volatile data (e.g., memory artifacts of running credential-dumping processes) or persistent evidence on disk. EDR isolation typically uses a host-based firewall rule to block all inbound/outbound traffic except to the EDR management channel, ensuring the host is quarantined without powering it off or altering the file system.
Key principle: Network isolation severs C2 without losing volatile data.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
✗
Allow the host to run until the next maintenance window
Why it's wrong here
Confirmed active compromise requires timely containment.
✓
Network-isolate the endpoint through EDR while preserving disk and memory evidence
Why this is correct
EDR isolation limits attacker communication without immediately destroying volatile forensic context.
Clue confirmation
The clue word "best" in the question point toward this answer.
Related concept
Network isolation severs C2 without losing volatile data.
✗
Run disk cleanup to remove temporary files
Why it's wrong here
Cleanup can destroy evidence and does not contain the threat.
✗
Power off the machine immediately in every case
Why it's wrong here
Powering off can destroy memory evidence and may not be the best first action when controlled isolation exists.
Common exam traps
Common exam trap: answer the scenario, not the keyword
Cisco often tests the misconception that 'preserving evidence' means you should not touch the host at all, leading candidates to choose 'allow the host to run' (option A), but the correct priority is to contain the threat immediately while using EDR's isolation feature to preserve both disk and memory evidence without powering down.
Detailed technical explanation
How to think about this question
EDR network isolation works by deploying a local firewall rule (e.g., via Windows Filtering Platform or iptables) that drops all packets except those to the EDR's management IP and port, effectively quarantining the host while allowing remote forensic collection. In a real-world scenario, credential-dumping tools like Mimikatz or lsass.exe process dumps leave artifacts in memory (e.g., plaintext credentials in the Windows Local Security Authority Subsystem Service) that are lost upon reboot, making live memory acquisition critical before any containment action that powers off the system.
KKey Concepts to Remember
Network isolation severs C2 without losing volatile data.
Memory forensics requires the system to remain powered on.
Containment balances threat mitigation with evidence preservation.
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
Network isolation severs C2 without losing volatile data.
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.
Security Operations — This question tests Security Operations — Network isolation severs C2 without losing volatile data..
What is the correct answer to this question?
The correct answer is: Network-isolate the endpoint through EDR while preserving disk and memory evidence — Network-isolating the endpoint through EDR (option B) is the best containment action because it immediately stops the beaconing to the malicious IP and prevents further credential dumping while preserving both disk and memory evidence for forensic analysis. This aligns with incident response best practices where containment must not destroy volatile data (e.g., memory artifacts of running credential-dumping processes) or persistent evidence on disk. EDR isolation typically uses a host-based firewall rule to block all inbound/outbound traffic except to the EDR management channel, ensuring the host is quarantined without powering it off or altering the file system.
What should I do if I get this CS0-003 question wrong?
Review network isolation severs C2 without losing volatile data., then practise related CS0-003 questions on the same topic to reinforce the concept.
Are there clue words in this question I should notice?
Yes — watch for: "best". Signals that multiple options may be partially correct. Choose the option that most directly solves the exact problem described, not the one that sounds most complete.
What is the key concept behind this question?
Network isolation severs C2 without losing volatile data.
About these practice questions
Courseiva creates original exam-style practice questions with explanations and wrong-answer analysis. It does not publish real exam questions, exam dumps, or protected exam content. Learn why practice questions differ from exam dumps →
Share a tip, memory trick, or ask about the reasoning behind this question. Do not post real exam questions, leaked content, braindumps, or copyrighted exam material. Comments are moderated and may be removed without notice.
This CS0-003 practice question is part of Courseiva's free CompTIA certification practice question bank. Courseiva provides original exam-style practice questions with explanations, topic-based practice, mock exams, readiness tracking, and study analytics to help learners prepare for the CS0-003 exam.
Question Discussion
Share a tip, memory trick, or ask about the reasoning behind this question. Do not post real exam questions, leaked content, braindumps, or copyrighted exam material. Comments are moderated and may be removed without notice.
Sign in to join the discussion.