DEA-C01 Data Security and Governance Practice Question

A data engineer needs to grant an IAM user read-only access to an S3 bucket named 'data-lake'. Which IAM policy statement should be used?

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

✓

{"Effect":"Allow","Action":["s3:ListBucket","s3:GetObject"],"Resource":["arn:aws:s3:::data-lake","arn:aws:s3:::data-lake/*"]}

It allows ListBucket on the bucket and GetObject on objects, enabling read-only access. Option A is wrong because it grants write actions (PutObject, DeleteObject). Option B is wrong because it allows all S3 actions (s3:*). Option D is wrong because it only allows ListBucket, not GetObject.

Answer analysis

Option-by-option breakdown

For each option: why learners choose it and why it is or isn't the right answer here.

✗
{"Effect":"Allow","Action":["s3:PutObject","s3:DeleteObject"],"Resource":"arn:aws:s3:::data-lake/*"}
Why it's wrong here
Allows write actions (PutObject, DeleteObject), so it is not read-only.
✗
{"Effect":"Allow","Action":"s3:*","Resource":"*"}
Why it's wrong here
Allows all S3 actions (s3:*), granting full access, not read-only.
✓
{"Effect":"Allow","Action":["s3:ListBucket","s3:GetObject"],"Resource":["arn:aws:s3:::data-lake","arn:aws:s3:::data-lake/*"]}
Why this is correct
Correctly allows ListBucket (list objects) and GetObject (read objects), providing read-only access.
✗
{"Effect":"Allow","Action":"s3:ListBucket","Resource":"arn:aws:s3:::data-lake"}
Why it's wrong here
Only allows ListBucket, so the user cannot read object contents.

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

DEA-C01 Data Security and Governance Practice Question

Why each option matters

Option-by-option breakdown

AWS S3 Storage Class Comparison

Related to this question