SC-900 Practice Question: Describe the concepts of security, compliance, and identity
A company secures its network by deploying a firewall at the perimeter, an intrusion prevention system on internal segments, endpoint antivirus on all workstations, and encrypting sensitive data at rest and in transit. This layered approach ensures that if one control fails, others still provide protection. Which security concept does this strategy best represent?
⚠ Common exam trap
A common mix-up: candidates confuse Zero Trust with defense in depth because both involve multiple controls, but Zero Trust specifically requires identity-based verification and micro-segmentation rather than relying on layered perimeter defenses.
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
The strategy described uses multiple independent security controls—firewall, IPS, endpoint antivirus, and encryption—so that if one layer fails, others continue to protect the asset. This is the core definition of defense in depth, which creates overlapping layers of protection rather than relying on 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.
- ✗
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 required functions, and no more. While crucial for reducing the attack surface by limiting potential damage from compromised accounts, this principle primarily addresses access rights and authorization management. It does not describe the deployment of a firewall as a *layered technical control* to create multiple defensive barriers against external threats.
When this WOULD be correct
A question that asks: 'A company configures user accounts so that employees can only access files necessary for their job roles. Which security concept does this represent?' would make least privilege the correct answer.
- ✓
Defense in depth
Why this is correct
Defense in depth is a comprehensive cybersecurity strategy that employs multiple, overlapping security controls to protect assets and data. By deploying a firewall, the company is establishing a perimeter defense, which constitutes one critical layer in a multi-layered security architecture. This approach ensures that if one security control fails or is bypassed, other controls are already in place to prevent or detect an intrusion, significantly enhancing overall resilience against various threats.
- ✗
Zero Trust
Why it's wrong here
Zero Trust is a security model based on 'never trust, always verify' and assumes breach. It focuses on continuous verification of every access request, not just deploying layered controls. While defense in depth can be part of a Zero Trust architecture, the scenario describes only the layered approach, not the full Zero Trust model.
- ✗
Separation of duties
Why it's wrong here
Separation of duties prevents a single person from having too much control over a critical process (e.g., one person requests a purchase, another approves). The scenario describes technical security layers, not task separation among people.
When this WOULD be correct
A question that asks: 'A company requires that no single employee can approve a payment and also initiate it; two different employees must perform these tasks. Which security concept does this represent?' Then 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 comprehensive cybersecurity strategy that employs multiple, overlapping security controls to protect assets and data. By deploying a firewall, the company is establishing a perimeter defense, which constitutes one critical layer in a multi-layered security architecture. This approach ensures that if one security control fails or is bypassed, other controls are already in place to prevent or detect an intrusion, significantly enhancing overall resilience against various threats.
✗Least privilegeWrong answer — click to see why▾
Why this is wrong here
The question describes multiple overlapping security controls (firewall, IPS, antivirus, encryption), which is the essence of defense in depth, not least privilege. Least privilege focuses on limiting user access rights, not layering defenses.
★ When this WOULD be the correct answer
A question that asks: 'A company configures user accounts so that employees can only access files necessary for their job roles. Which security concept does this represent?' would make least privilege the correct answer.
Why candidates choose this
Candidates may confuse least privilege with defense in depth because both are fundamental security principles, but least privilege is about access control, not layered defenses.
✗Separation of dutiesWrong answer — click to see why▾
Why this is wrong here
The question describes a layered security approach with multiple controls, which is defense in depth, not separation of duties. Separation of duties is about dividing tasks among multiple people to prevent fraud or error, not about overlapping security controls.
★ When this WOULD be the correct answer
A question that asks: 'A company requires that no single employee can approve a payment and also initiate it; two different employees must perform these tasks. Which security concept does this represent?' Then separation of duties would be correct.
Why candidates choose this
Candidates may confuse 'separation of duties' with 'defense in depth' because both involve multiple layers or divisions, but separation of duties is about dividing responsibilities among people, not about overlapping technical controls.
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
IPS
An Intrusion Prevention System (IPS) is a network security device that monitors traffic in real time and automatically blocks threats before they reach your systems.
Key term
Encryption
Encryption is the process of converting readable data into a secret code to prevent unauthorized access.
About these practice questions
This SC-900 question is part of Courseiva's 1,250-question bank — original exam-style content with full explanations and wrong-answer analysis, never real exam questions or exam dumps. Learn why practice questions differ from exam dumps →
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.