The answer is to create an interface VPC endpoint for Secrets Manager and another interface VPC endpoint for KMS, enabling private DNS for both. This configuration is correct because it allows the EC2 instance in a private subnet, which lacks a NAT gateway, to access both services entirely over the AWS network using private IP addresses, keeping all traffic off the internet. Enabling private DNS ensures that the standard service endpoints for Secrets Manager and KMS resolve to the endpoint’s private IPs, so no route to the internet is needed. On the SAA-C03 exam, this scenario tests your understanding of VPC endpoints for private access to AWS services, and a common trap is to create only one endpoint for Secrets Manager while forgetting that the customer managed KMS key also requires its own interface endpoint. A useful memory tip is “two keys, two endpoints” — a customer managed KMS key always demands a separate VPC endpoint alongside the service it protects.
SAA-C03 Design Secure Architectures Practice Question
This SAA-C03 practice question tests your understanding of design secure architectures. Match the stated requirement to the specific cloud service, access model, or configuration option — many options are valid in isolation but not for this scenario. After answering, compare your reasoning against the explanation and wrong-answer breakdown below. Once you have made your selection, read the full explanation to reinforce the concept and understand why each distractor is designed to mislead on exam day.
Exhibit
VPC configuration:
- Subnet-Private-A route table: local 10.0.0.0/16 only
- Subnet-Private-B route table: local 10.0.0.0/16 only
- No 0.0.0.0/0 route to an Internet Gateway or NAT Gateway
Existing endpoints:
- com.amazonaws.us-east-1.s3 (Gateway endpoint)
Application log:
ERROR: Unable to retrieve secret arn:aws:secretsmanager:us-east-1:111122223333:secret:prod/api/db
ERROR: connect timeout to secretsmanager.us-east-1.amazonaws.com
ERROR: KMS Decrypt access not completed
Based on the exhibit, an EC2 application runs in private subnets with no NAT gateway and must retrieve a secret from AWS Secrets Manager. The secret uses a customer managed KMS key. Which change will allow the application to reach the service while keeping traffic off the internet?
VPC configuration:
- Subnet-Private-A route table: local 10.0.0.0/16 only
- Subnet-Private-B route table: local 10.0.0.0/16 only
- No 0.0.0.0/0 route to an Internet Gateway or NAT Gateway
Existing endpoints:
- com.amazonaws.us-east-1.s3 (Gateway endpoint)
Application log:
ERROR: Unable to retrieve secret arn:aws:secretsmanager:us-east-1:111122223333:secret:prod/api/db
ERROR: connect timeout to secretsmanager.us-east-1.amazonaws.com
ERROR: KMS Decrypt access not completed
A
Create an interface VPC endpoint for Secrets Manager and another interface VPC endpoint for KMS, and enable private DNS for both.
Secrets Manager is an interface endpoint service, and the customer managed KMS key means the application also needs private access to KMS for decrypt operations. Private DNS lets the SDK resolve standard service names to the VPC endpoints, keeping all traffic inside AWS private networking.
B
Create an S3 gateway endpoint for Secrets Manager and use the existing S3 gateway endpoint for both secret retrieval and KMS decryption.
Why wrong: Gateway endpoints are not used for Secrets Manager or KMS. They are specifically for supported services such as S3 and DynamoDB. The existing S3 endpoint does not provide network path or name resolution for the secret or decrypt operations.
C
Add a NAT gateway in a public subnet and route 0.0.0.0/0 from the private subnets to the NAT gateway.
Why wrong: A NAT gateway would allow outbound internet access, but the requirement says to keep traffic off the internet. It would also introduce additional cost and does not meet the private connectivity constraint. AWS PrivateLink endpoints are the correct design.
D
Move the application into a public subnet so it can call the public Secrets Manager endpoint directly.
Why wrong: Moving the workload to a public subnet increases exposure and violates the stated requirement to avoid internet egress. The goal is private service access from private subnets, not public internet connectivity.
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
Create an interface VPC endpoint for Secrets Manager and another interface VPC endpoint for KMS, and enable private DNS for both.
Option A is correct because it creates interface VPC endpoints for both Secrets Manager and KMS, which allows the EC2 instance in the private subnet to securely access these services over the AWS network without traversing the internet. Enabling private DNS ensures that the standard service endpoints resolve to the private IP addresses of the VPC endpoints, eliminating the need for a NATgateway or internet gateway.
Key principle: Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
✓
Create an interface VPC endpoint for Secrets Manager and another interface VPC endpoint for KMS, and enable private DNS for both.
Why this is correct
Secrets Manager is an interface endpoint service, and the customer managed KMS key means the application also needs private access to KMS for decrypt operations. Private DNS lets the SDK resolve standard service names to the VPC endpoints, keeping all traffic inside AWS private networking.
Related concept
Read the scenario before looking for a memorised answer.
✗
Create an S3 gateway endpoint for Secrets Manager and use the existing S3 gateway endpoint for both secret retrieval and KMS decryption.
Why it's wrong here
Gateway endpoints are not used for Secrets Manager or KMS. They are specifically for supported services such as S3 and DynamoDB. The existing S3 endpoint does not provide network path or name resolution for the secret or decrypt operations.
✗
Add a NAT gateway in a public subnet and route 0.0.0.0/0 from the private subnets to the NAT gateway.
Why it's wrong here
A NATgateway would allow outbound internet access, but the requirement says to keep traffic off the internet. It would also introduce additional cost and does not meet the private connectivity constraint. AWS PrivateLink endpoints are the correct design.
✗
Move the application into a public subnet so it can call the public Secrets Manager endpoint directly.
Why it's wrong here
Moving the workload to a public subnet increases exposure and violates the stated requirement to avoid internet egress. The goal is private service access from private subnets, not public internet connectivity.
Common exam traps
Common exam trap: answer the scenario, not the keyword
The trap here is that candidates often assume a single endpoint type (like a gateway endpoint) can serve all AWS services, but Secrets Manager and KMS specifically require interface endpoints, and forgetting the KMS endpoint is a common oversight.
Detailed technical explanation
How to think about this question
Interface VPC endpoints use AWS PrivateLink to provide private connectivity by creating an elastic network interface (ENI) in the subnet with a private IP address, allowing traffic to stay within the AWS network. Secrets Manager and KMS both require interface endpoints because they are not supported by gateway endpoints; gateway endpoints only work with S3 and DynamoDB. In a real-world scenario, if the KMS key is customer managed, the application must also call KMS to decrypt the secret, so both endpoints are necessary.
KKey Concepts to Remember
Read the scenario before looking for a memorised answer.
Find the constraint that changes the correct option.
Eliminate answers that are true in general but not in this case.
TExam Day Tips
→Watch for words such as best, first, most likely and least administrative effort.
→Review why wrong options are wrong, not only why the correct option is correct.
Key takeaway
Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
Real-world example
How this comes up in practice
A media company stores terabytes of video archives that are accessed once a year for audit purposes. Moving these objects to a cold storage tier (Azure Archive, S3 Glacier, or Google Nearline) costs a fraction of hot storage. Questions like this test whether you understand storage tiers, access frequency tradeoffs, and retrieval latency requirements.
What to study next
Got this wrong? Here's your next step.
Identify which exam domain this question belongs to, review the core concept, then practise similar questions from the same domain.
Design Secure Architectures — This question tests Design Secure Architectures — Read the scenario before looking for a memorised answer..
What is the correct answer to this question?
The correct answer is: Create an interface VPC endpoint for Secrets Manager and another interface VPC endpoint for KMS, and enable private DNS for both. — Option A is correct because it creates interface VPC endpoints for both Secrets Manager and KMS, which allows the EC2 instance in the private subnet to securely access these services over the AWS network without traversing the internet. Enabling private DNS ensures that the standard service endpoints resolve to the private IP addresses of the VPC endpoints, eliminating the need for a NAT gateway or internet gateway.
What should I do if I get this SAA-C03 question wrong?
Identify which exam domain this question belongs to, review the core concept, then practise similar questions from the same domain.
What is the key concept behind this question?
Read the scenario before looking for a memorised answer.
About these practice questions
Courseiva creates original exam-style practice questions with explanations and wrong-answer analysis. It does not publish real exam questions, exam dumps, or protected exam content. Learn why practice questions differ from exam dumps →
These questions test the same concept from different angles. Work through them to make sure you can recognise it however the exam phrases it.
Variation 1. Based on the exhibit, an application runs in private subnets without a NAT gateway and must retrieve a secret from AWS Secrets Manager. Security requires the traffic to stay on the AWS network and not traverse the public internet. What is the best solution?
hard
A.Add a NAT gateway to the private subnet route table and keep using the public Secrets Manager endpoint.
✓ B.Create an interface VPC endpoint for Secrets Manager and enable private DNS for the endpoint.
C.Create a gateway VPC endpoint for Secrets Manager and point the route table to it.
D.Use VPC peering to connect the application subnet to another VPC that already has internet access.
Why B: Option B is correct because an interface VPC endpoint for Secrets Manager allows the application in the private subnet to securely access Secrets Manager over the AWS network using private IP addresses, without needing a NAT gateway or internet gateway. Enabling private DNS ensures that the default Secrets Manager DNS name resolves to the endpoint's private IP addresses, keeping all traffic within the AWS backbone and satisfying the security requirement.
Last reviewed: Jun 11, 2026
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