The correct actions are to isolate the device from the network and block the file hash of the malware in Microsoft Defender for Endpoint indicators. Device isolation immediately cuts off network communication, preventing the compromised endpoint from spreading the threat to other systems, while blocking the file hash in indicators of compromise (IoC) stops the malware from executing on any other device, effectively containing lateral movement. On the SC-200 exam, this scenario tests your understanding of Microsoft Defender for Endpoint’s response capabilities, specifically the difference between reactive containment (isolation) and proactive prevention (hash blocking). A common trap is choosing to run a full scan or reset passwords, but these do not instantly stop lateral spread. Remember the memory tip: “Isolate the host, block the ghost”—the host is the device, and the ghost is the malicious file hash.
SC-200 Respond to security incidents Practice Question
This SC-200 practice question tests your understanding of respond to security incidents. 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.
Your organization uses Microsoft 365 Defender. You are investigating a potential malware outbreak on several endpoints. Which TWO actions should you take to isolate affected devices and prevent lateral movement?
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
Use Microsoft Defender for Endpoint to initiate device isolation on affected devices.
Options B and D are correct. Isolating devices from the network (B) prevents communication with other devices, and blocking the malicious file hash (D) prevents execution on other endpoints. Option A is wrong because resetting passwords does not stop lateral movement. Option C is wrong because running a full scan takes time and does not immediately isolate. Option E is wrong because deleting user accounts is too drastic and not focused on lateral movement.
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.
✓
Use Microsoft Defender for Endpoint to initiate device isolation on affected devices.
Read the scenario before looking for a memorised answer.
✗
Run a full antivirus scan on all endpoints.
Why it's wrong here
Scanning is reactive and does not immediately stop lateral movement.
✗
Reset the passwords of all users on the affected devices.
Why it's wrong here
Password reset does not prevent lateral movement via malware.
✗
Delete the user accounts that logged into the affected devices.
Why it's wrong here
Deleting accounts is excessive and not focused on malware containment.
✓
Block the file hash of the malware in Microsoft Defender for Endpoint indicators.
Why this is correct
Blocking the hash prevents execution on other endpoints.
Related concept
Read the scenario before looking for a memorised answer.
Common exam traps
Common exam trap: answer the scenario, not the keyword
Many certification questions include familiar terms but test a specific constraint. Read the exact wording before choosing an answer that is generally true but wrong for this case.
Detailed technical explanation
How to think about this question
This question should be treated as a scenario, not a definition check. Identify the problem, the constraint and the best action. Then compare each option against those facts.
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.
Use explanations to understand the rule behind the answer.
TExam Day Tips
→Underline the problem statement mentally.
→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 healthcare organisation deploys an application with a public-facing web tier and a private database tier. The database subnet has no public IP and only accepts connections from the web tier's security group. Questions like this test whether you can design cloud network isolation using VNets/VPCs, subnets, and security group rules.
Related glossary terms
Concepts from this question explained
These glossary pages explain the core terms tested in this SC-200 question in full detail.
Identify which SC-200 exam domain this question belongs to, then review the specific concept being tested. Practise related questions in that domain and focus on understanding why each wrong answer is tempting — not just why the correct answer is right.
Respond to security incidents — This question tests Respond to security incidents — Read the scenario before looking for a memorised answer..
What is the correct answer to this question?
The correct answer is: Use Microsoft Defender for Endpoint to initiate device isolation on affected devices. — Options B and D are correct. Isolating devices from the network (B) prevents communication with other devices, and blocking the malicious file hash (D) prevents execution on other endpoints. Option A is wrong because resetting passwords does not stop lateral movement. Option C is wrong because running a full scan takes time and does not immediately isolate. Option E is wrong because deleting user accounts is too drastic and not focused on lateral movement.
What should I do if I get this SC-200 question wrong?
Identify which SC-200 exam domain this question belongs to, then review the specific concept being tested. Practise related questions in that domain and focus on understanding why each wrong answer is tempting — not just why the correct answer is right.
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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