DVA-C02 Security Practice Question
A developer needs to prevent accidental public access to all S3 buckets in an account. Which account-level control should be enabled?
⚠ Common exam trap
Candidates often confuse bucket-level controls (like bucket policies or ACLs) with account-level controls, or mistakenly think features like Transfer Acceleration or Inventory provide security, when only S3 Block Public Access offers a centralized, account-wide safeguard against public exposure.
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
✓
S3 Block Public Access
S3 Block Public Access is an account-level control that provides a centralized way to enforce that no S3 buckets or objects in the account can be made publicly accessible, regardless of individual bucket policies or ACLs. This setting overrides any bucket-level public access settings, effectively preventing accidental exposure of data to the internet.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
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S3 Transfer Acceleration
Why it's wrong here
S3 Transfer Acceleration is a feature designed to speed up data transfers to and from S3 buckets over long distances by utilizing Amazon CloudFront's globally distributed edge locations. It optimizes the network path between the client and the S3 bucket, reducing latency and improving throughput. However, this feature is solely focused on performance enhancement for data ingress and egress, and it provides no mechanisms or controls to prevent or block public access to S3 buckets or their objects.
- ✓
S3 Block Public Access
Why this is correct
S3 Block Public Access is the correct and most effective service for preventing accidental public access to S3 buckets and objects across an entire AWS account or specific buckets. It offers four distinct settings that can be applied at the account or bucket level: blocking new public ACLs, ignoring existing public ACLs, blocking new public bucket policies, and blocking public and cross-account access to buckets with public policies. These controls override other access configurations, ensuring strong protection against unintended public exposure.
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S3 Inventory
Why it's wrong here
S3 Inventory is a tool that generates daily or weekly reports listing objects and their corresponding metadata for a bucket or a shared prefix. These reports can include details such as object size, storage class, encryption status, and replication status, which are useful for auditing and managing storage. However, S3 Inventory is purely an analytical and reporting feature; it does not provide any active controls or enforcement mechanisms to prevent or block public access to S3 resources.
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S3 Object Lambda
Why it's wrong here
S3 Object Lambda allows developers to add custom code to process data retrieved from S3 before it is returned to an application. This enables on-the-fly transformations like redacting sensitive information, resizing images, or converting data formats. While it can modify the content of an object during retrieval, S3 Object Lambda is not designed to prevent public access to the underlying S3 objects or enforce bucket-level access policies. It operates on the data stream, not on the access control layer.
Quick reference
AWS S3 Storage Class Comparison
| Storage Class | Min Duration | Retrieval | Use Case |
|---|---|---|---|
| S3 Standard | None | Immediate | Frequently accessed data |
| S3 Standard-IA | 30 days | Immediate | Infrequent access, rapid retrieval |
| S3 One Zone-IA | 30 days | Immediate | Non-critical infrequent data |
| S3 Intelligent-Tiering | None | Immediate–hours | Unknown or changing access patterns |
| S3 Glacier Instant | 90 days | Milliseconds | Archive with instant retrieval |
| S3 Glacier Flexible | 90 days | Minutes–hours | Archive, flexible retrieval |
| S3 Glacier Deep Archive | 180 days | Hours | Long-term compliance archive |
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JA
Written by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
This DVA-C02 practice question is part of Courseiva's free Amazon Web Services 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 DVA-C02 exam.