SC-900 Practice Question: Describe the concepts of security, compliance, and identity
A company implements multiple layers of security controls: firewalls at the perimeter, intrusion detection systems on internal segments, antivirus software on all workstations, and encryption for sensitive data at rest and in transit. This strategy is intended to ensure that if one control fails, others still provide protection. Which security concept does this approach represent?
⚠ Common exam trap
Candidates often confuse defense in depth with zero trust, mistakenly thinking that multiple layers automatically imply a zero-trust architecture, but zero trust specifically requires explicit verification per request rather than just layered controls.
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 concept because it involves implementing multiple layers of security controls (e.g., firewalls, IDS, antivirus, encryption) so that if one layer fails, subsequent layers continue to provide protection. This layered approach ensures redundancy and mitigates the risk of a single point of failure, aligning with the scenario described.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
Least privilege
Why it's wrong here
The principle of least privilege dictates that users, programs, or processes should be granted only the minimum necessary permissions to perform their specific functions and nothing more. This fundamental security practice limits the potential damage an attacker can inflict if an account or system is compromised, as the compromised entity will only have restricted access to resources. It is an access control mechanism focused on minimizing the attack surface of individual entities and limiting the blast radius, not a strategy for layering diverse security technologies across an environment.
When this WOULD be correct
A scenario where a company restricts user access rights so that employees can only access the data and systems required for their job roles, with no unnecessary permissions. The question would ask about minimizing exposure to sensitive data.
- ✓
Defense in depth
Why this is correct
Defense in depth is a comprehensive cybersecurity strategy that employs a series of diverse and overlapping security mechanisms and controls to protect valuable assets. By implementing multiple layers—such as physical security, network segmentation, firewalls, intrusion detection systems, endpoint protection, and data encryption—organizations create a robust and resilient defense. This multi-layered approach ensures that if one security control fails or is bypassed, subsequent layers are still in place to detect and prevent a breach, significantly increasing the effort and time required for an attacker to succeed.
- ✗
Separation of duties
Why it's wrong here
Separation of duties is an administrative control designed to prevent fraud, error, or unauthorized actions by requiring multiple individuals to complete distinct parts of a critical task or process. This principle ensures that no single person has complete control over a sensitive operation, thereby reducing the risk of malicious activity or honest mistakes going undetected. It focuses on distributing responsibilities among personnel to mitigate insider threats, rather than establishing technical layers of security controls within a system architecture.
When this WOULD be correct
A company requires that no single employee can approve a purchase order and also process the payment. This ensures that two people must collaborate to complete a financial transaction, reducing the risk of embezzlement. This scenario tests separation of duties.
- ✗
Zero trust
Why it's wrong here
Zero Trust is a security model that operates on the principle of 'never trust, always verify,' meaning no user, device, or application is implicitly trusted, regardless of its location inside or outside the network perimeter. Every access request is rigorously authenticated, authorized, and continuously validated based on context, such as user identity, device health, and the sensitivity of the service being accessed. While a Zero Trust architecture may incorporate various security controls, its core tenet is continuous verification and granular access control, rather than the mere presence of multiple, static security layers as its defining characteristic.
When this WOULD be correct
A question describing a network architecture where no device or user is trusted by default, even if inside the corporate perimeter, and every access request must be authenticated and authorized regardless of location. For example: 'A company implements micro-segmentation, requires multi-factor authentication for all internal resource access, and continuously validates device health before granting access.'
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 comprehensive cybersecurity strategy that employs a series of diverse and overlapping security mechanisms and controls to protect valuable assets. By implementing multiple layers—such as physical security, network segmentation, firewalls, intrusion detection systems, endpoint protection, and data encryption—organizations create a robust and resilient defense. This multi-layered approach ensures that if one security control fails or is bypassed, subsequent layers are still in place to detect and prevent a breach, significantly increasing the effort and time required for an attacker to succeed.
✗Least privilegeWrong answer — click to see why▾
Why this is wrong here
The question describes multiple layers of security controls (firewalls, IDS, antivirus, encryption) working together to provide protection even if one fails. This is the definition of defense in depth, not least privilege, which focuses on granting only necessary permissions.
★ When this WOULD be the correct answer
A scenario where a company restricts user access rights so that employees can only access the data and systems required for their job roles, with no unnecessary permissions. The question would ask about minimizing exposure to sensitive data.
Why candidates choose this
Candidates may confuse 'least privilege' with the layered approach because both involve security controls, but least privilege is about access rights, not overlapping defenses.
✗Separation of dutiesWrong answer — click to see why▾
Why this is wrong here
Separation of duties prevents fraud or error by dividing critical tasks among multiple people, not by layering security controls. The question describes multiple overlapping security layers, which is defense in depth, not separation of duties.
★ When this WOULD be the correct answer
A company requires that no single employee can approve a purchase order and also process the payment. This ensures that two people must collaborate to complete a financial transaction, reducing the risk of embezzlement. This scenario tests separation of duties.
Why candidates choose this
Candidates may confuse 'separation of duties' with 'multiple layers of defense' because both involve multiple components, but separation of duties is about dividing responsibilities among people, not layering technical controls.
✗Zero trustWrong answer — click to see why▾
Why this is wrong here
Zero trust is a security model that assumes no implicit trust and requires continuous verification of every access request, not a layered defense strategy. The question describes multiple overlapping controls, which is defense in depth, not zero trust.
★ When this WOULD be the correct answer
A question describing a network architecture where no device or user is trusted by default, even if inside the corporate perimeter, and every access request must be authenticated and authorized regardless of location. For example: 'A company implements micro-segmentation, requires multi-factor authentication for all internal resource access, and continuously validates device health before granting access.'
Why candidates choose this
Candidates may confuse zero trust with defense in depth because both involve multiple security controls, but zero trust specifically focuses on eliminating implicit trust and verifying every access, not on layered protection against failure of a single control.
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?”
Go deeper
Related to this question
Learn chapter
Core Security Concepts
Key term
Redundancy
Redundancy is the practice of adding extra components or systems so that if one fails, another can take over without interruption.
Key term
Antivirus
Antivirus is software that detects, prevents, and removes malicious software (malware) from a computer or network.
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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.