The answer is automated investigation and response (AIR) capabilities in Microsoft Defender XDR. This is the correct feature because AIR contains built-in, automated playbooks that, upon detecting a malicious file, can execute a device isolation action to immediately cut the affected endpoint off from the network, preventing lateral movement while the investigation runs. On the Microsoft Cybersecurity Architect exam, this scenario tests your understanding of how Defender XDR’s automation engine handles response actions without manual intervention, often appearing in questions that contrast AIR with manual incident response or conditional access policies. A common trap is confusing device isolation with a block action on a file; remember that isolation targets the entire device, not just the file. A helpful memory tip is “AIR isolates the host, not the ghost”—the automation isolates the physical or virtual machine, not the malicious process itself.
SC-100 Practice Question: Design solutions that align with security best practices and priorities
This SC-100 practice question tests your understanding of design solutions that align with security best practices and priorities. This is a configuration task: choose the command set that satisfies every stated requirement. Small differences — like 'secret' vs 'password' or 'transport input ssh' vs 'all' — change whether the answer is correct. 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 company uses Microsoft Defender XDR to protect endpoints. The security team wants to implement automated response actions when a malicious file is detected on a device. Which Microsoft security feature should you configure to automatically isolate the affected device from the network?
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
Automated investigation and response (AIR) capabilities
Automated investigation and response (AIR) in Microsoft Defender XDR is the correct feature because it includes built-in playbooks that can automatically isolate a device from the network when a malicious file is detected. AIR leverages the Microsoft 365 Defender portal's automation capabilities to run investigation steps and execute response actions, such as device isolation, without manual intervention. This directly meets the requirement for automated response upon file detection.
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.
✓
Automated investigation and response (AIR) capabilities
Why this is correct
AIR in Microsoft Defender XDR can automatically isolate devices upon detection of malicious activity.
Related concept
Read the scenario before looking for a memorised answer.
✗
Microsoft Sentinel automation rules
Why it's wrong here
Microsoft Sentinel automation rules can trigger playbooks but are not native for endpoint isolation.
✗
Attack surface reduction rules
Why it's wrong here
Attack surface reduction rules reduce exploit vectors but do not perform automated device isolation.
✗
Microsoft Intune compliance policies
Why it's wrong here
Intune compliance policies mark devices as non-compliant but do not trigger automatic isolation.
Common exam traps
Common exam trap: answer the scenario, not the keyword
The trap here is that candidates often confuse the proactive prevention capabilities of Attack surface reduction rules with the automated response capabilities of AIR, or they overestimate the real-time response abilities of Intune compliance policies, which are designed for configuration enforcement rather than incident response actions like network isolation.
Detailed technical explanation
How to think about this question
Under the hood, AIR in Defender XDR uses a set of predefined playbooks that run on the Microsoft 365 backend, leveraging the Common Event Format (CEF) and the Microsoft Defender for Endpoint APIs to execute actions like 'Isolate device' (which sends a command to the endpoint via the Defender sensor to block all network traffic except to the Defender cloud service). In a real-world scenario, if a device triggers a high-confidence malware alert, AIR can automatically isolate it within seconds, preventing lateral movement while the investigation continues, and the isolation can be lifted manually or automatically after remediation.
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 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-100 question in full detail.
Design solutions that align with security best practices and priorities — This question tests Design solutions that align with security best practices and priorities — Read the scenario before looking for a memorised answer..
What is the correct answer to this question?
The correct answer is: Automated investigation and response (AIR) capabilities — Automated investigation and response (AIR) in Microsoft Defender XDR is the correct feature because it includes built-in playbooks that can automatically isolate a device from the network when a malicious file is detected. AIR leverages the Microsoft 365 Defender portal's automation capabilities to run investigation steps and execute response actions, such as device isolation, without manual intervention. This directly meets the requirement for automated response upon file detection.
What should I do if I get this SC-100 question wrong?
Identify which exam domain this question belongs to, review the core concept, then practise similar questions from the same domain.
What is the key concept behind this question?
Read the scenario before looking for a memorised answer.
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