The answer is Microsoft Defender for Cloud's Just-in-time (JIT) VM access. This solution directly addresses the need for just-in-time VM access for RDP security by keeping inbound ports like 3389 closed by default, then dynamically opening them only for a specified time window and approved source IP after a portal-based request. On the SC-900 exam, this scenario tests your understanding of how Microsoft Defender for Cloud reduces the attack surface through time-limited, request-driven port control, often appearing as a scenario where you must distinguish JIT from always-on solutions like network security groups or Azure Bastion. A common trap is confusing JIT with Bastion, but remember: Bastion provides persistent, browser-based RDP/SSH without opening any public ports, while JIT temporarily opens specific ports to specific IPs. Memory tip: think “JIT = Just In Time, just enough access, just for your IP, just for a few hours.”
SC-900 Practice Question: Describe the capabilities of Microsoft security solutions
This SC-900 practice question tests your understanding of describe the capabilities of microsoft security solutions. The scenario asks you to isolate a root cause — eliminate options that address a different problem before choosing. 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.
A company runs critical Windows virtual machines on Azure. To reduce the attack surface, the security team wants to block all inbound RDP (port 3389) traffic from the internet by default. When a security engineer needs to connect via RDP for troubleshooting, they must request access through a portal, and the RDP port will be opened for a limited time (e.g., 4 hours) only to their source IP address. Which Microsoft security solution should they use to implement this control?
Microsoft Defender for Cloud's Just-in-time (JIT) VM access
Defender for Cloud's JIT VM access provides exactly this capability: controls inbound traffic to VMs, reduces exposure, and grants temporary access with approval.
B
Microsoft Defender for Cloud Apps
Why wrong: Defender for Cloud Apps is for securing third-party cloud apps and SaaS applications, not for Azure VM network access.
C
Microsoft Defender for Endpoint
Why wrong: Defender for Endpoint is an endpoint security solution for EDR, not for managing VM network access.
D
Azure Network Security Groups (NSGs) with application security groups
Why wrong: NSGs can block traffic, but they do not provide the approval workflow, time-limited access, or automatic source IP restriction that JIT offers.
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
Microsoft Defender for Cloud's Just-in-time (JIT) VM access
Microsoft Defender for Cloud's Just-in-time (JIT) VM access is the correct solution because it specifically provides time-limited, request-based opening of inbound ports (such as RDP port 3389) to approved source IP addresses, reducing the attack surface by keeping ports closed by default. This aligns directly with the requirement to block all inbound RDP from the internet by default and allow temporary access only through a portal request.
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.
✓
Microsoft Defender for Cloud's Just-in-time (JIT) VM access
Why this is correct
Defender for Cloud's JIT VM access provides exactly this capability: controls inbound traffic to VMs, reduces exposure, and grants temporary access with approval.
Related concept
Read the scenario before looking for a memorised answer.
✗
Microsoft Defender for Cloud Apps
Why it's wrong here
Defender for Cloud Apps is for securing third-party cloud apps and SaaS applications, not for Azure VM network access.
✗
Microsoft Defender for Endpoint
Why it's wrong here
Defender for Endpoint is an endpoint security solution for EDR, not for managing VM network access.
✗
Azure Network Security Groups (NSGs) with application security groups
Why it's wrong here
NSGs can block traffic, but they do not provide the approval workflow, time-limited access, or automatic source IP restriction that JIT offers.
Common exam traps
Common exam trap: answer the scenario, not the keyword
The trap here is that candidates may confuse network-level controls (NSGs) with a managed security service that automates temporary access, leading them to choose Option D without realizing NSGs lack the time-limited, request-based workflow that JIT provides.
Detailed technical explanation
How to think about this question
JIT VM access works by integrating with Azure Network Security Groups (NSGs) and Azure Firewall policies to dynamically create and remove allow rules for specific source IPs and ports. When an engineer requests access, Defender for Cloud validates the request against policies (e.g., max allowed time, approved ports) and temporarily modifies the NSG rule to allow traffic, then automatically reverts the rule after the time expires. This ensures that even if an attacker scans the VM, port 3389 appears closed except during authorized sessions.
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 company's IT admin needs to give a contractor read-only access to production logs without sharing account credentials. Using role-based access control (RBAC) and temporary scoped permissions — not a permanent shared password — is the correct pattern. Questions like this test whether you can apply least-privilege access across cloud identity services.
Related glossary terms
Concepts from this question explained
These glossary pages explain the core terms tested in this SC-900 question in full detail.
Describe the capabilities of Microsoft security solutions — This question tests Describe the capabilities of Microsoft security solutions — Read the scenario before looking for a memorised answer..
What is the correct answer to this question?
The correct answer is: Microsoft Defender for Cloud's Just-in-time (JIT) VM access — Microsoft Defender for Cloud's Just-in-time (JIT) VM access is the correct solution because it specifically provides time-limited, request-based opening of inbound ports (such as RDP port 3389) to approved source IP addresses, reducing the attack surface by keeping ports closed by default. This aligns directly with the requirement to block all inbound RDP from the internet by default and allow temporary access only through a portal request.
What should I do if I get this SC-900 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.
About these practice questions
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Variation 1. A company uses Azure virtual machines for a production database. The security team wants to minimize the attack surface by blocking all inbound RDP (port 3389) traffic. However, administrators occasionally need to connect for maintenance. The team needs a solution that allows administrators to request temporary access to the RDP port, which is automatically revoked after a specified time. Which Microsoft Defender for Cloud feature should they use?
easy
A.Adaptive application controls
✓ B.Just-in-time (JIT) VM access
C.File Integrity Monitoring (FIM)
D.Security alerts
Why B: Just-in-time (JIT) VM access is the correct feature because it specifically addresses the need to block inbound RDP (port 3389) traffic by default while allowing administrators to request temporary, time-bound access. When a request is approved, JIT dynamically modifies the network security group (NSG) to open the port for a specified duration, then automatically reverts the rule to deny all inbound traffic after the time expires. This directly minimizes the attack surface by eliminating persistent open management ports.
Last reviewed: Jun 11, 2026
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This SC-900 practice question is part of Courseiva's free Microsoft 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 SC-900 exam.
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