SC-100 Practice Question: Design security solutions for applications and data
Your organization is deploying a new line-of-business application on Azure App Service. The app must authenticate users from Microsoft Entra ID and also access a downstream API that requires a client secret. You need to recommend the most secure method for managing the client secret. What should you use?
⚠ Common exam trap
SC-100 often tests the misconception that App Service application settings are secure because they are 'encrypted' — candidates may pick option B, but the exam expects Key Vault with managed identity as the only answer that provides centralized, auditable, rotatable secret management.
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
✓
Store the secret in Azure Key Vault and use a Key Vault reference in App Service.
Storing the client secret in Azure Key Vault and referencing it from App Service via a Key Vault reference is the most secure method. Key Vault provides centralized secret management, access control via Entra ID, auditing, rotation capabilities, and hardware-backed protection (HSM) for keys. App Service can resolve Key Vault references at runtime using its managed identity, so the secret never appears in application settings or code.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
Store the secret in the Microsoft Entra ID app registration manifest.
Why it's wrong here
Storing the secret in the Microsoft Entra ID app registration manifest is insecure because the manifest is a configuration file that can be exported or exposed, and it does not provide the same security controls as a dedicated secret store.
- ✗
Store the secret in an App Service application setting.
Why it's wrong here
App Service application settings are stored in plain text within the Azure environment and can be accessed through the portal, APIs, or configuration management tools, making them less secure than using Key Vault with managed identity.
- ✓
Store the secret in Azure Key Vault and use a Key Vault reference in App Service.
Why this is correct
Correct. Azure Key Vault provides secure, centralized storage for secrets with encryption and access auditing. App Service can reference Key Vault secrets via Key Vault references, using a managed identity to authenticate without exposing the secret.
- ✗
Store the secret in the application code as a constant.
Why it's wrong here
Hard-coding a secret as a constant is insecure because the plaintext value becomes part of the source code and compiled binary. It can be exposed through source control history, decompilation, debug dumps, or logging, and it persists on disk in deployment artifacts. Any code review, leak of a repo, or compromise of a build pipeline immediately reveals the secret, and rotating it requires a full application redeployment rather than a centralized update.
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JA
Written and reviewed by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
Last reviewed September 2026 · checked against the official Microsoft exam blueprint
This SC-100 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-100 exam.