Quick Answer
The correct answer is to configure the 'Client apps' condition under 'Conditions' in a Conditional Access policy to block legacy authentication. This is because legacy protocols like POP3, IMAP4, and SMTP do not support modern authentication methods such as MFA or device compliance, making them a primary vector for credential-based attacks. By targeting the 'Client apps' condition, administrators can enforce a blanket block on all non-modern authentication attempts across Microsoft Entra ID, effectively closing this security gap. On the SC-900 exam, this concept tests your understanding of how Conditional Access policies granularly control sign-in risks; a common trap is confusing the 'Client apps' condition with the 'Grant' or 'Assignments' sections. Remember the memory tip: "Legacy apps get blocked in the Conditions—not the Grants."
This SC-900 practice question tests your understanding of describe the capabilities of microsoft security solutions. 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.
A security administrator needs to block legacy authentication protocols across all applications in Microsoft Entra ID. Which conditional access policy setting should they configure?
Under 'Grant', select 'Block access'
Why wrong: Blocks all access, not just legacy auth.
Under 'Conditions', configure 'Locations' to block all locations
Why wrong: Controls geographic access, not authentication protocols.
Set 'Sign-in frequency' to 1 hour
Why wrong: Controls how often reauthentication is required.
Under 'Conditions', configure 'Client apps' to block legacy authentication
Specifically targets legacy authentication protocols.
Answer choices
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
Under 'Conditions', configure 'Client apps' to block legacy authentication
Option D is correct because legacy authentication protocols (such as POP3, IMAP4, SMTP, and older Office clients) do not support modern authentication methods like MFA or conditional access. By configuring the 'Client apps' condition in a Conditional Access policy to block legacy authentication, the administrator can prevent these insecure sign-in attempts across all applications in Microsoft Entra ID.
Key principle: Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
Answer analysis
For each option: why learners choose it and why it is or isn't the right answer here.
Under 'Grant', select 'Block access'
Why it's wrong here
Blocks all access, not just legacy auth.
Under 'Conditions', configure 'Locations' to block all locations
Why it's wrong here
Controls geographic access, not authentication protocols.
Set 'Sign-in frequency' to 1 hour
Why it's wrong here
Controls how often reauthentication is required.
Under 'Conditions', configure 'Client apps' to block legacy authentication
Why this is correct
Specifically targets legacy authentication protocols.
Related concept
Read the scenario before looking for a memorised answer.
Common exam traps
The trap here is that candidates may confuse 'Block access' under 'Grant' (which is a general block) with the specific condition needed to target legacy protocols, or they may think that location or sign-in frequency settings can address protocol-level restrictions.
Detailed technical explanation
Legacy authentication protocols such as POP3, IMAP4, SMTP, and Exchange ActiveSync (without modern auth) rely on basic authentication, which sends credentials in plaintext and cannot enforce MFA or device compliance. Conditional Access policies evaluate the 'Client apps' condition to detect these protocols via the 'Exchange ActiveSync clients' and 'Other clients' options, allowing administrators to block them while still permitting modern OAuth 2.0-based clients. In real-world scenarios, organizations often combine this with a policy that grants access only to compliant devices or requires MFA for modern clients, ensuring a layered security approach.
Key takeaway
Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
Real-world example
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.
What to study next
Identify which exam domain this question belongs to, review the core concept, then practise similar questions from the same domain.
Describe the capabilities of Microsoft security solutions — study guide chapter
Learn the concepts, then practise the questions
Describe the capabilities of Microsoft security solutions practice questions
Targeted practice on this topic area only
All SC-900 questions
1,411 questions across all exam domains
Microsoft Security, Compliance, and Identity Fundamentals SC-900 study guide
Full concept coverage aligned to exam objectives
SC-900 practice test guide
How to use practice tests most effectively before exam day
Related practice questions
Use these pages to review the topic behind this question. This is how one missed question becomes focused revision.
Practise SC-900 questions linked to Describe the capabilities of Microsoft Entra.
Practise SC-900 questions linked to Describe the capabilities of Microsoft security solutions.
Practise SC-900 questions linked to Describe the capabilities of Microsoft compliance solutions.
Practise SC-900 questions linked to Describe the concepts of security, compliance, and identity.
Practise SC-900 questions linked to SC-900 fundamentals.
Practise SC-900 questions linked to SC-900 scenario.
Practise SC-900 questions linked to SC-900 troubleshooting.
Practice this exam
Short sessions build daily habit. Longer sessions build exam-day stamina. Try a timed session to simulate real conditions.
FAQ
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..
The correct answer is: Under 'Conditions', configure 'Client apps' to block legacy authentication — Option D is correct because legacy authentication protocols (such as POP3, IMAP4, SMTP, and older Office clients) do not support modern authentication methods like MFA or conditional access. By configuring the 'Client apps' condition in a Conditional Access policy to block legacy authentication, the administrator can prevent these insecure sign-in attempts across all applications in Microsoft Entra ID.
Identify which exam domain this question belongs to, review the core concept, then practise similar questions from the same domain.
Read the scenario before looking for a memorised answer.
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 →
Last reviewed: Jun 24, 2026
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.
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.