SAA-C03 Design Secure Architectures Practice Question
A Lambda function for a mobile banking backend needs to read a database password. The password must rotate automatically every 30 days and should not be stored in environment variables. Which service should be used? The design must avoid adding custom operational scripts.
⚠ Common exam trap
It's easy for candidates to confuse AWS Systems Manager Parameter Store SecureString (which can store secrets but lacks automatic rotation) with Secrets Manager, or they assume that encrypting environment variables with KMS is sufficient for rotation, ignoring the need for automated lifecycle management.
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
✓
AWS Secrets Manager with rotation enabled
AWS Secrets Manager is the correct choice because it natively supports automatic rotation of secrets on a configurable schedule (e.g., every 30 days) without requiring custom scripts. It also provides fine-grained access control and integrates directly with Lambda via the AWS SDK, keeping the password out of environment variables and code.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
An encrypted object in Amazon S3
Why it's wrong here
An S3 object provides no native rotation mechanism and Lambda would need custom code to fetch and decrypt it, breaching the no-scripts requirement. S3 storage is correct for large unstructured datasets or static artefacts, not for credentials needing scheduled rotation.
- ✓
AWS Secrets Manager with rotation enabled
Why this is correct
Secrets Manager natively rotates credentials on a schedule using built-in Lambda rotation functions, satisfying the 30-day rotation requirement without custom scripts. It also keeps the password out of environment variables, unlike plain Lambda configuration or SSM Parameter Store without rotation logic.
- ✗
AWS Systems Manager Parameter Store SecureString without automation
Why it's wrong here
SecureString encrypts the value but Parameter Store performs no native rotation, so meeting the 30-day cycle requires custom automation, which the design forbids. Parameter Store is correct for static configuration and secrets where rotation is handled externally or not required.
- ✗
A KMS-encrypted Lambda environment variable
Why it's wrong here
A KMS-encrypted environment variable still stores the password in Lambda configuration, violating the requirement, and KMS alone cannot rotate it every 30 days without custom scripts. KMS encryption suits protecting static configuration data, not managing rotating database credentials.
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.