SAA-C03 Design Secure Architectures Practice Question
A startup runs an API on Amazon EC2. The instance must read items from one DynamoDB table and upload logs to one S3 bucket. Platform engineers also need a way to create new application roles, but those roles must never exceed a predefined set of permissions. Which three actions should the architect take? Select three.
⚠ Common exam trap
Many candidates think storing access keys in a config file with rotation is acceptable, but AWS explicitly recommends using IAM roles for EC2 to avoid the security risks of long-lived static credentials.
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
✓
Attach an IAM role to the EC2 instance profile and remove long-lived access keys from the server.
Option A is correct because attaching an IAM role to the EC2 instance profile lets the instance obtain temporary credentials from the instance metadata service (IMDS) via AWS STS, eliminating the need for long-lived access keys on the server. Option C is correct because least-privilege policies should scope permissions to the specific resources needed — the exact DynamoDB table ARN and the S3 bucket/prefix ARN — rather than granting broad access. Option E is correct because a permissions boundary sets the maximum permissions an IAM role can have, so even if the platform team creates new application roles, those roles can never exceed the predefined boundary. Option B is wrong because an IAM user with administrator access violates least privilege and embedding IAM user credentials on an instance is an anti-pattern. Option D is wrong because storing long-lived access keys in a configuration file is insecure and rotation does not remove the underlying risk that instance roles solve.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✓
Attach an IAM role to the EC2 instance profile and remove long-lived access keys from the server.
Why this is correct
An IAM role attached to the EC2 instance profile supplies temporary credentials via instance metadata, so the application reads DynamoDB and writes to S3 without embedded long-lived access keys. Removing those keys eliminates a persistent credential that could be leaked or rotated manually.
- ✗
Give the EC2 instance an IAM user with administrator access for simplicity.
Why it's wrong here
Administrator access on an IAM user attached to the instance grants far more than the DynamoDB read and S3 log upload the API needs, and IAM users cannot be constrained by the predefined ceiling. It is tempting for speed, but an instance profile role with a permissions boundary is correct.
- ✓
Scope the application policy to the exact DynamoDB table ARN and S3 bucket prefix.
Why this is correct
Scoping the policy to the specific DynamoDB table ARN and S3 bucket prefix enforces least privilege, granting only the exact resources the API needs. Broad wildcard permissions would violate the requirement that roles never exceed the predefined permission set.
- ✗
Store the access keys in the application configuration file and rotate them later.
Why it's wrong here
Long-lived access keys stored in a configuration file are static credentials that cannot enforce the predefined permission ceiling and risk leakage. It is tempting because embedding keys works for quick prototypes, but IAM roles with scoped policies and permissions boundaries satisfy the requirement.
- ✓
Use a permissions boundary for any IAM roles the platform team is allowed to create.
Why this is correct
A permissions boundary defines the maximum permissions any role the platform team creates can hold, even if their identity policies allow more. This enforces the constraint that newly created application roles never exceed the predefined permission ceiling.
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 SAA-C03 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 SAA-C03 exam.