SAP-C02 Design for New Solutions Practice Question

A company wants to provide temporary, limited-privilege credentials to its application running on an EC2 instance so that the application can access an S3 bucket. What is the BEST practice for achieving this?

⚠ Common exam trap

Watch out — candidates often think storing credentials in user data or code is acceptable for automation, but AWS explicitly prohibits this in favor of IAM roles for EC2 to avoid long-term credential 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

✓

Create an IAM role with the necessary permissions and attach it to the EC2 instance

The best practice is to use an IAM role, which provides temporary security credentials via the EC2 instance metadata service (IMDS). The application automatically retrieves these credentials without hardcoding secrets, and the credentials are rotated automatically by AWS. This approach follows the principle of least privilege and eliminates the security risks of long-term access keys.

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 to allow access from the EC2 instance's public IP
Why it's wrong here
Bucket policies control access from IPs, but do not provide credentials; also, IPs can change.
✗
Create an IAM user and store the credentials in the EC2 instance user data
Why it's wrong here
IAM user credentials are long-term and should not be stored on instances; they are not temporary.
✗
Store AWS access keys in the application code
Why it's wrong here
Storing access keys in code is insecure and not a best practice; they can be exposed.
✓
Create an IAM role with the necessary permissions and attach it to the EC2 instance
Why this is correct
An IAM role provides temporary credentials that are automatically rotated, which is secure and best practice.

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

SAP-C02 Design for New Solutions Practice Question

Why each option matters

Option-by-option breakdown

AWS S3 Storage Class Comparison

Related to this question