What is the MOST operationally efficient solution that meets these requirements?

A company asks a SysOps administrator to ensure that AWS CloudTrail files are not tampered with after they are created. Currently, the company uses AWS Identity and Access Management (IAM) to restrict access to specific trails. The company’s security team needs the ability to trace the integrity of each file.

What is the MOST operationally efficient solution that meets these requirements?
A . Create an Amazon EventBridge (Amazon CloudWatch Events) rule that invokes an AWS Lambda function when a new file is delivered. Configure the Lambda function to compute an MD5 hash check on the file and store the result in an Amazon DynamoDB table. The security team can use the values that are stored in DynamoDB to verify the integrity of the delivered files.
B. Create an AWS Lambda function that is invoked each time a new file is delivered to the CloudTrail bucket. Configure the Lambda function to compute an MD5 hash check on the file and store the result as a tag in an Amazon S3 object. The security team can use the information in the tag to verify the integrity of the delivered files.
C. Enable the CloudTrail file integrity feature on an Amazon S3 bucket. Create an IAM policy that grants the security team access to the file integrity logs that are stored in the S3 bucket.
D. Enable the CloudTrail file integrity feature on the trail. The security team can use the digest file that is created by CloudTrail to verify the integrity of the delivered files.

View Answer

Answer: D

Explanation:

https://docs.aws.amazon.com/awscloudtrail/latest/userguide/cloudtrail-log-file-validation-intro.html

"When you enable log file integrity validation, CloudTrail creates a hash for every log file that it delivers. Every hour, CloudTrail also creates and delivers a file that references the log files for the last hour and contains a hash of each. This file is called a digest file. Validated log files are invaluable in security and forensic investigations"