AWS Certified Security – Specialty (SCS-C02) — Question 174

A company has a batch-processing system that uses Amazon S3, Amazon EC2, and AWS Key Management Service (AWS KMS). The system uses two AWS accounts: Account A and Account B.

Account A hosts an S3 bucket that stores the objects that will be processed. The S3 bucket also stores the results of the processing. All the S3 bucket objects are encrypted by a KMS key that is managed in Account A.

Account B hosts a VPC that has a fleet of EC2 instances that access the S3 bucket in Account A by using statements in the bucket policy. The VPC was created with DNS hostnames enabled and DNS resolution enabled.

A security engineer needs to update the design of the system without changing any of the system's code. No AWS API calls from the batch-processing EC2 instances can travel over the internet.

Which combination of steps will meet these requirements? (Choose two.)

Answer options

• A. In the Account B VPC, create a gateway VPC endpoint for Amazon S3. For the gateway VPC endpoint, create a resource policy that allows the s3:GetObject, s3:ListBucket, s3:PutObject, and s3:PutObjectAcl actions for the S3 bucket.
• B. In the Account B VPC, create an interface VPC endpoint for Amazon S3. For the interface VPC endpoint, create a resource policy that allows the s3:GetObject, s3:ListBucket, s3:PutObject, and s3:PutObjectAcl actions for the S3 bucket.
• C. In the Account B VPC, create an interface VPC endpoint for AWS KMS. For the interface VPC endpoint, create a resource policy that allows the kms:Encrypt, kms:Decrypt, and kms:GenerateDataKey actions for the KMS key. Ensure that private DNS is turned on for the endpoint.
• D. In the Account B VPC, create an interface VPC endpoint for AWS KMS. For the interface VPC endpoint, create a resource policy that allows the kms:Encrypt, kms:Decrypt, and kms:GenerateDataKey actions for the KMS key. Ensure that private DNS is turned off for the endpoint.
• E. In the Account B VPC, verify that the S3 bucket policy allows the s3:PutObjectAcl action for cross-account use. In the Account B VPC, create a gateway VPC endpoint for Amazon S3. For the gateway VPC endpoint, create a resource policy that allows the s3:GetObject, s3:ListBucket, and s3:PutObject actions for the S3 bucket.

Correct answer: A, C

Explanation

The correct steps are A and C. Option A correctly sets up a gateway VPC endpoint for Amazon S3, ensuring that access to the S3 bucket remains within the AWS network. Option C is necessary for allowing EC2 instances to utilize the KMS key in Account A securely. The other options either utilize the wrong type of VPC endpoint or do not ensure proper DNS settings for KMS usage.