The answer is Just-In-Time (JIT) VM access in Microsoft Defender for Cloud. This feature directly reduces the attack surface of management ports by keeping inbound traffic to your virtual machines locked down by default, only opening specific ports like RDP (3389) or SSH (22) when an authorized user requests access and for a limited, approved time window. On the Azure AZ-900 exam, this concept tests your understanding of how Defender for Cloud provides proactive security controls beyond just monitoring—it’s a key example of a workload protection service that enforces the principle of least privilege. A common trap is confusing JIT with Azure Bastion; remember that Bastion provides a secure jump box without exposing public IPs, while JIT dynamically opens and closes ports on existing VMs. For a quick memory tip, think “JIT = Just In Time, Just In Case—ports open only when you need them, then they vanish.”
AZ-900 Describe Azure architecture and services Practice Question
This AZ-900 practice question tests your understanding of describe azure architecture and services. Match the stated requirement to the specific cloud service, access model, or configuration option — many options are valid in isolation but not for this scenario. 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.
Which Azure feature provides Just-In-Time (JIT) VM access to reduce the attack surface of management ports?
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
JIT VM Access in Microsoft Defender for Cloud
Just-In-Time (JIT) VM access in Microsoft Defender for Cloud reduces the attack surface by locking down inbound traffic to VMs, only opening management ports (e.g., RDP port 3389 or SSH port 22) when requested and for a specific time window. This is the correct feature because it directly implements JIT access to management ports, as described in the question.
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.
✗
Azure Bastion
Why it's wrong here
Bastion provides browser-based RDP/SSH without public IPs; JIT reduces NSG rules opening on private ports.
✓
JIT VM Access in Microsoft Defender for Cloud
Why this is correct
JIT VM Access temporarily opens management ports only when needed, closing them automatically after the session.
Related concept
Read the scenario before looking for a memorised answer.
✗
Azure AD Privileged Identity Management
Why it's wrong here
PIM manages privileged identity activation; JIT manages network port access for VM management.
✗
Azure Key Vault Certificate access
Why it's wrong here
Key Vault certificates manage SSL certificates; JIT manages time-limited VM port access.
Common exam traps
Common exam trap: answer the scenario, not the keyword
The trap here is confusing Azure Bastion (which provides persistent secure access) with JIT VM Access (which dynamically opens and closes ports on demand), as both relate to securing VM management but solve different problems.
Detailed technical explanation
How to think about this question
JIT VM Access works by creating network security group (NSG) rules that deny inbound traffic to management ports by default; when a user requests access, Defender for Cloud temporarily creates an allow rule for their IP address and specified port, then automatically removes it after the configured duration (default 3 hours). This leverages Azure Resource Manager templates and NSG flow logs to audit all access requests, and can be integrated with Azure Policy to enforce JIT across all VMs in a subscription.
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 AZ-900 question in full detail.
Describe Azure architecture and services — This question tests Describe Azure architecture and services — Read the scenario before looking for a memorised answer..
What is the correct answer to this question?
The correct answer is: JIT VM Access in Microsoft Defender for Cloud — Just-In-Time (JIT) VM access in Microsoft Defender for Cloud reduces the attack surface by locking down inbound traffic to VMs, only opening management ports (e.g., RDP port 3389 or SSH port 22) when requested and for a specific time window. This is the correct feature because it directly implements JIT access to management ports, as described in the question.
What should I do if I get this AZ-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.
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Question Discussion
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