SC-900 Practice Question: Describe the concepts of security, compliance, and identity
A security manager explains that the company's security strategy relies on multiple layers of controls, such as firewalls, antivirus software, and multi-factor authentication, so that if one layer fails, another can still prevent an attack. Which security principle does this strategy best represent?
⚠ Common exam trap
Watch out — candidates often confuse Zero Trust with defense in depth because both involve multiple controls, but Zero Trust is specifically about verifying every access request regardless of origin, whereas defense in depth is about layering independent controls to provide redundancy and depth.
Answer choices
Why each option matters
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
Defense in depth
Defense in depth is the correct answer because it explicitly describes a layered security strategy where multiple independent controls (firewalls, antivirus, MFA) are deployed so that if one layer is bypassed or fails, subsequent layers still provide protection. This principle is foundational to modern security architecture and directly matches the scenario of using diverse controls to prevent a single point of failure.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✓
Defense in depth
Why this is correct
Defense in depth is a cybersecurity strategy that employs multiple, overlapping security controls and mechanisms to protect assets across various layers of an organization's infrastructure. This layered approach ensures that if one security control fails or is bypassed, other controls are in place to detect and prevent unauthorized access or malicious activity. It provides redundancy and resilience, significantly increasing the effort and time required for an attacker to compromise a system or data.
- ✗
Least privilege
Why it's wrong here
The principle of least privilege dictates that users, processes, and applications should be granted only the minimum necessary permissions to perform their legitimate functions. This approach minimizes the potential damage from a security breach or error by restricting an attacker's lateral movement and access to sensitive resources. It focuses on limiting individual access rights rather than establishing multiple, distinct layers of security controls.
When this WOULD be correct
A question asks: 'A company wants to ensure employees only have access to the data required for their job roles. Which security principle should be applied?' In that context, least privilege would be correct.
- ✗
Zero Trust
Why it's wrong here
Zero Trust is a security model based on the principle of 'never trust, always verify,' meaning no user or device is inherently trusted, regardless of their location inside or outside the network perimeter. Every access request is authenticated, authorized, and continuously validated based on identity, device health, and other contextual factors. While Zero Trust architectures may incorporate various security controls, its core tenet is about continuous verification rather than simply layering defenses.
When this WOULD be correct
An exam scenario where a company implements strict access policies, verifies every request regardless of origin, and assumes breach—such as requiring authentication for all internal network traffic and using micro-segmentation—would make Zero Trust the correct answer.
- ✗
Separation of duties
Why it's wrong here
Separation of duties is an administrative control designed to prevent fraud, errors, and abuse by ensuring that no single individual has complete control over a critical process or transaction. It requires multiple individuals to complete distinct parts of a task, thereby distributing responsibilities and requiring collusion for malicious acts. This principle focuses on human processes and accountability, rather than the technical layering of security technologies.
When this WOULD be correct
A question that asks: 'A company requires that no single employee can approve a payment and also process the refund; these tasks must be performed by two different people. Which security principle does this represent?' In that scenario, separation of duties would be correct.
Option-by-option analysis
Why each answer is right or wrong
Understanding why wrong answers are wrong — and when they would be correct — is what separates a 750 score from a 900. The SC-900 exam frequently reuses these exact scenarios with slightly different constraints.
✓Defense in depthCorrect answer▾
Why this is correct
Defense in depth is a cybersecurity strategy that employs multiple, overlapping security controls and mechanisms to protect assets across various layers of an organization's infrastructure. This layered approach ensures that if one security control fails or is bypassed, other controls are in place to detect and prevent unauthorized access or malicious activity. It provides redundancy and resilience, significantly increasing the effort and time required for an attacker to compromise a system or data.
✗Least privilegeWrong answer — click to see why▾
Why this is wrong here
The question describes multiple layers of controls (firewalls, antivirus, MFA) that work together to prevent attacks if one fails. Least privilege is about granting only necessary access rights, not layering defenses.
★ When this WOULD be the correct answer
A question asks: 'A company wants to ensure employees only have access to the data required for their job roles. Which security principle should be applied?' In that context, least privilege would be correct.
Why candidates choose this
Candidates may confuse 'least privilege' with a general security best practice, but it specifically addresses access rights, not layered defenses.
✗Zero TrustWrong answer — click to see why▾
Why this is wrong here
The question describes multiple layers of controls (firewalls, antivirus, MFA) to prevent attack if one fails, which is the definition of defense in depth. Zero Trust is a security model that assumes no implicit trust and requires continuous verification, not specifically about layered controls.
★ When this WOULD be the correct answer
An exam scenario where a company implements strict access policies, verifies every request regardless of origin, and assumes breach—such as requiring authentication for all internal network traffic and using micro-segmentation—would make Zero Trust the correct answer.
Why candidates choose this
Candidates may confuse Zero Trust with defense in depth because both involve multiple security measures, but Zero Trust focuses on 'never trust, always verify' rather than layered redundancy.
✗Separation of dutiesWrong answer — click to see why▾
Why this is wrong here
The question describes multiple layers of security controls (firewalls, antivirus, MFA) working together, which is the definition of defense in depth. Separation of duties is about dividing tasks among different people to prevent fraud or error, not about layered defenses.
★ When this WOULD be the correct answer
A question that asks: 'A company requires that no single employee can approve a payment and also process the refund; these tasks must be performed by two different people. Which security principle does this represent?' In that scenario, separation of duties would be correct.
Why candidates choose this
Candidates may confuse 'separation of duties' with 'layered controls' because both involve multiple components, but separation of duties is about dividing responsibilities among people, not about technical defense layers.
Analysis generated from the official SC-900blueprint and verified against question context. The “when correct” sections are what AI assistants cite when candidates ask “what’s the difference between these options?”
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JA
Written by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
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.