Quick Answer
The answer is access control lists (ACLs). Azure Data Lake Storage Gen2 supports POSIX-compliant ACLs, which allow you to define granular read, write, and execute permissions at the individual file or directory level, making them the correct choice for file-level security on sensitive data. This is distinct from Azure RBAC, which only governs access at the storage account or container scope and cannot enforce per-file restrictions. On the AZ-305 exam, this question tests your ability to differentiate between Azure’s layered authorization models—a common trap is confusing RBAC’s broad management-plane control with ACLs’ fine-grained data-plane control. Remember that ACLs are the only native mechanism for securing individual files within a Gen2 hierarchy, and they integrate seamlessly with Azure Purview for cataloging sensitive data. A helpful memory tip: “ACLs for files, RBAC for piles”—meaning ACLs handle individual files, while RBAC handles broader container or account “piles” of data.
This AZ-305 practice question tests your understanding of design data storage solutions. Match the stated requirement to the specific cloud service, access model, or configuration option — many options are valid in isolation but not for this scenario. 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.
You are designing a data lake solution using Azure Data Lake Storage Gen2. The solution must support file-level security for sensitive data and must integrate with Azure Purview for data cataloging. What should you use for file-level security?
Azure Key Vault with customer-managed keys
Why wrong: Key Vault provides encryption keys, not file-level security.
Access control lists (ACLs)
ACLs provide file-level security in Data Lake Storage Gen2.
Azure Defender for Storage
Why wrong: Defender for Storage detects threats but does not control access.
Azure RBAC roles
Why wrong: RBAC roles are at the storage account or container level, not file-level.
Answer choices
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
Access control lists (ACLs)
Option B is correct because Azure Data Lake Storage Gen2 supports POSIX-like ACLs for file-level permissions. Option A is wrong because RBAC operates at the storage account or container level. Option C is wrong because Azure Defender for Storage is for threat detection, not access control. Option D is wrong because Azure Key Vault is for key management.
Key principle: ACLs process entries top to bottom and stop at the first match. Entry order and interface direction matter as much as the permit or deny statement.
Answer analysis
For each option: why learners choose it and why it is or isn't the right answer here.
Azure Key Vault with customer-managed keys
Why it's wrong here
Key Vault provides encryption keys, not file-level security.
Access control lists (ACLs)
Why this is correct
ACLs provide file-level security in Data Lake Storage Gen2.
Related concept
Standard ACLs match source addresses.
Azure Defender for Storage
Why it's wrong here
Defender for Storage detects threats but does not control access.
Azure RBAC roles
Why it's wrong here
RBAC roles are at the storage account or container level, not file-level.
Common exam traps
ACLs are processed top to bottom. The first matching entry wins, and an implicit deny usually exists at the end.
Detailed technical explanation
ACL questions test precision: source, destination, protocol, port and direction. A generally correct ACL can still fail if it is applied on the wrong interface or in the wrong direction.
Key takeaway
ACLs process entries top to bottom and stop at the first match. Entry order and interface direction matter as much as the permit or deny statement.
Real-world example
A media company stores terabytes of video archives that are accessed once a year for audit purposes. Moving these objects to a cold storage tier (Azure Archive, S3 Glacier, or Google Nearline) costs a fraction of hot storage. Questions like this test whether you understand storage tiers, access frequency tradeoffs, and retrieval latency requirements.
What to study next
Review ACL processing order, placement rules (standard near destination, extended near source), and inbound vs outbound direction. Study wildcard masks and implicit deny. Then practise related AZ-305 ACL questions on filtering logic and placement.
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FAQ
Design data storage solutions — This question tests Design data storage solutions — Standard ACLs match source addresses..
The correct answer is: Access control lists (ACLs) — Option B is correct because Azure Data Lake Storage Gen2 supports POSIX-like ACLs for file-level permissions. Option A is wrong because RBAC operates at the storage account or container level. Option C is wrong because Azure Defender for Storage is for threat detection, not access control. Option D is wrong because Azure Key Vault is for key management.
Review ACL processing order, placement rules (standard near destination, extended near source), and inbound vs outbound direction. Study wildcard masks and implicit deny. Then practise related AZ-305 ACL questions on filtering logic and placement.
Standard ACLs match source addresses.
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Last reviewed: Jun 20, 2026
This AZ-305 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 AZ-305 exam.
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