Explanation
Log validation should be activated on Cloudtrail logs to prevent the tampering of the underlying data in the S3 bucket. It is feasible that a rogue actor compromising an AWS account might want to modify the log data to remove trace of their actions.
Insecure Example
The following example will fail the AWS064 check.
resource "aws_cloudtrail" "bad_example" {
is_multi_region_trail = true
event_selector {
read_write_type = "All"
include_management_events = true
data_resource {
type = "AWS::S3::Object"
values = ["${data.aws_s3_bucket.important-bucket.arn}/"]
}
}
}Secure Example
The following example will pass the AWS064 check.
resource "aws_cloudtrail" "good_example" {
is_multi_region_trail = true
enable_log_file_validation = true
event_selector {
read_write_type = "All"
include_management_events = true
data_resource {
type = "AWS::S3::Object"
values = ["${data.aws_s3_bucket.important-bucket.arn}/"]
}
}
}