No Public Log Access

The S3 Bucket backing Cloudtrail should be private

CloudTrail logs a record of every API call made in your account. These log files are stored in an S3 bucket. CIS recommends that the S3 bucket policy, or access control list (ACL), applied to the S3 bucket that CloudTrail logs to prevents public access to the CloudTrail logs. Allowing public access to CloudTrail log content might aid an adversary in identifying weaknesses in the affected account’s use or configuration.

Impact

CloudTrail logs will be publicly exposed, potentially containing sensitive information

Recommended Actions

Follow the appropriate remediation steps below to resolve the issue.

 1
 2
 3
 4
 5
 6
 7
 8
 9
10
11
12
13

Resources:
  GoodExampleTrail:
    Type: AWS::CloudTrail::Trail
    Properties:
      IsLogging: true
      S3BucketName: "my-bucket"
      TrailName: "Cloudtrail"
  GoodExampleBucket:
    Type: AWS::S3::Bucket
    Properties:
      BucketName: "my-bucket"
      AccessControl: Private

 1
 2
 3
 4
 5
 6
 7
 8
 9
10
11
12
13
14
15
16
17
18
19
20

 resource "aws_cloudtrail" "good_example" {
   is_multi_region_trail = true
   s3_bucket_name = "abcdefgh"
 
   event_selector {
     read_write_type           = "All"
     include_management_events = true
 
     data_resource {
       type = "AWS::S3::Object"
       values = ["${data.aws_s3_bucket.important-bucket.arn}/"]
     }
   }
 }

resource "aws_s3_bucket" "good_example" {
	bucket = "abcdefgh"
	acl = "private"
}
 

Links

• https://docs.aws.amazon.com/AmazonS3/latest/userguide/configuring-block-public-access-bucket.html