CCSP Cloud Platform and Infrastructure Security Practice Question
A cloud security team needs to ensure that an Amazon EC2 instance hosting a regulated workload cannot communicate with the public internet, but the instance must still be able to download OS patches from an internal repository and retrieve secrets from AWS Secrets Manager. The workload runs in a private subnet with no NAT gateway or internet gateway route. Which combination of configurations will meet these requirements with the LEAST operational overhead?
⚠ Common exam trap
The trap here is assuming that a NAT gateway or restrictive firewall rules satisfy a 'no public internet' requirement, when in fact any route to an internet gateway or NAT device still constitutes public internet connectivity.
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 VPC interface endpoints (AWS PrivateLink) for Secrets Manager and an S3 gateway endpoint for the patch repository, and associate the endpoints with the private subnet's route table and security group.
VPC interface endpoints (AWS PrivateLink) and S3 gateway endpoints let resources in private subnets reach AWS services entirely over the AWS private network, with no internet gateway, NAT, or public IP required. This satisfies the no-internet constraint, supports both patch retrieval and secret access, and requires minimal ongoing operational effort compared to firewall or NAT-based designs.
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 internet gateway to the VPC and use a security group that allows only outbound HTTPS to the patch server and Secrets Manager endpoints.
Why it's wrong here
An internet gateway provides bidirectional internet connectivity for resources with public IP addresses or an attached elastic IP, which directly violates the requirement that the instance cannot reach the public internet. Even with restrictive security group rules, the route to the internet gateway still exists and represents an unacceptable exposure for a regulated workload. A more controlled, private path is required instead.
- ✗
Place the instance in a public subnet and use an AWS Network Firewall policy to block all outbound traffic except the patch server and Secrets Manager IP ranges.
Why it's wrong here
Placing the instance in a public subnet exposes it to inbound internet routing and contradicts the private-subnet requirement. AWS Network Firewall adds significant cost and configuration complexity compared to VPC endpoints, and IP-based allowlisting is brittle because service IPs change. This approach increases operational overhead while still leaving the instance in a publicly routable subnet.
- ✗
Deploy a NAT gateway in a public subnet and update the private subnet route table to direct 0.0.0.0/0 through the NAT gateway, then restrict outbound traffic using network ACLs.
Why it's wrong here
A NAT gateway still provides outbound internet connectivity, which breaks the explicit requirement that the instance must not communicate with the public internet. Restricting traffic with network ACLs does not remove the route to the internet and introduces additional stateful/stateless rule management overhead. Regulated workloads needing private-only access should avoid NAT-based egress entirely.
- ✓
Create VPC interface endpoints (AWS PrivateLink) for Secrets Manager and an S3 gateway endpoint for the patch repository, and associate the endpoints with the private subnet's route table and security group.
Why this is correct
Interface endpoints for Secrets Manager and a gateway endpoint for S3 keep traffic on the AWS private network without any internet gateway or NAT device. Associating the endpoints with the subnet route table and allowing the endpoint security group to accept traffic from the instance satisfies both patch retrieval and secret access while eliminating public exposure. This is the lowest-overhead, most auditable design.
Visual reference
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 and reviewed by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
Last reviewed September 2026 · checked against the official ISC2 exam blueprint
This CCSP practice question is part of Courseiva's free ISC2 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 CCSP exam.