AWS Certified Security – Specialty SCS-C01 – Question146

An Application team has requested a new AWS KMS master key for use with Amazon S3, but the organizational security policy requires separate master keys for different AWS services to limit blast radius.
How can an AWS KMS customer master key (CMK) be constrained to work with only Amazon S3?

A.
Configure the CMK key policy to allow only the Amazon S3 service to use the kms:Encrypt action.
B. Configure the CMK key policy to allow AWS KMS actions only when the kms:ViaService condition matches the Amazon S3 service name.
C. Configure the IAM user’s policy to allow KMS to pass a role to Amazon S3.
D. Configure the IAM user’s policy to allow only Amazon S3 operations when they are combined with the CMK.

Correct Answer: B

Explanation: