ANS-C01 Network Security, Compliance and Governance Practice Question
Which THREE of the following are valid ways to restrict access to an S3 bucket that is accessed by EC2 instances in a VPC?
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
✓
Use an S3 bucket policy that restricts access to the VPC or VPC endpoint.
Options A, C, and D are correct. Option A: S3 bucket policies can restrict access based on source VPC or VPC endpoint. Option C: VPC endpoint policies can specify which S3 buckets can be accessed through the endpoint. Option D: IAM roles (instance profiles) grant permissions to EC2 instances to access S3 buckets. Option B is incorrect because network ACLs operate at the subnet level and do not filter by S3 bucket; they only filter based on IP addresses. Option E is incorrect because security groups do not apply to S3 bucket access; they control traffic to/from EC2 instances.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✓
Use an S3 bucket policy that restricts access to the VPC or VPC endpoint.
Why this is correct
S3 bucket policies can use aws:SourceVpc or aws:SourceVpce conditions.
- ✗
Use a network ACL to restrict access to the S3 prefix list.
Why it's wrong here
NACLs can allow S3 prefix list IPs, but not restrict to a specific bucket.
- ✓
Use a VPC endpoint policy to allow access only to the specific S3 bucket.
Why this is correct
VPC endpoint policies can limit access to specific buckets.
- ✓
Use an IAM role (instance profile) attached to the EC2 instance with permissions for the S3 bucket.
Why this is correct
Instance profiles provide credentials that can be used to access S3.
- ✗
Use a security group to allow outbound traffic from the EC2 instance to the S3 bucket.
Why it's wrong here
Security groups do not filter by S3 bucket; they filter by IP.
Visual reference
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 |
Go deeper
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JA
Written by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
This ANS-C01 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 ANS-C01 exam.