Q50 — AWS SCS-C02 Ch.1

Question 50 of 100 | ← Chapter 1

A security engineer for a large company is managing a data processing application used by 1,500 subsidiary companies. The parent and subsidiary companies all use AWS. The application uses TCP port 443 and runs on Amazon C2 behind a Network Load Balancer (NLB). For compliance reasons, the application should only be accessible to the subsidiaries and should not be available on the public internet. To meet the compliance requirements for restricted access, the engineer has received the public and private CIDR block ranges for each subsidiary. What solution should the engineer use to implement the appropriate access restrictions for the application?

• A. Create a NACL to allow access on TCP port 443 from the 1,500 subsidiary CIDR block ranges. Associate the NACL to both the NLB and EC2 instances.
• B. Create an AWS security group to allow access on TCP port 443 from the 1,500 subsidiary CIDR block ranges. Associate the security group to the NLCreate a second security group for EC2 instances with access on TCP port 443 from the NLB security group.
• C. Create an AWS PrivateLink endpoint service in the parent company account attached to the NLB. Create an AWS security group for the instances to allow access on TCP port 443 from the AWS PrivateLink endpoint. Use AWS PrivateLink interface endpoints in the 1,500 subsidiary AWS accounts to connect to the data processing application. ✓
• D. Create an AWS security group to allow access on TCP port 443 from the 1,500 subsidiary CIDR block ranges. Associate the security group with EC2 instances.

Correct Answer: C. Create an AWS PrivateLink endpoint service in the parent company account attached to the NLB. Create an AWS security group for the instances to allow access on TCP port 443 from the AWS PrivateLink endpoint. Use AWS PrivateLink interface endpoints in the 1,500 subsidiary AWS accounts to connect to the data processing application.

Explanation

该题涉及在AWS环境中限制应用程序访问权限以满足合规性要求。AWS安全最佳实践推荐使用VPC端点服务（如PrivateLink）实现私有连接，避免公开暴露于互联网。AWS文档指出，PrivateLink允许在不同账户和VPC之间通过私有网络流量访问服务，无需通过公共互联网。选项C通过创建PrivateLink端点服务并关联到NLB，结合安全组限制仅允许来自该端点的流量，确保子公司通过私有接口端点连接，满足仅内部访问的需求。其他选项或错误使用NACL（不适合动态NLB环境），或误将安全组关联到不支持安全组的NLB，或在管理大量CIDR时存在维护难题。