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Version: 4.2.0

How to Find AWS CloudTrail Trails Not Encrypted with KMS Keys

By default, the log files delivered by CloudTrail to your bucket are encrypted by Amazon server-side encryption with Amazon S3-managed encryption keys (SSE-S3). To provide a security layer that is directly manageable, you can instead use server-side encryption with AWS KMS–managed keys (SSE-KMS) for your CloudTrail log files.

info

This security check is part of the CIS Amazon Web Services Benchmarks and is rated severity medium.

Prerequisites​

This guide assumes that you have already installed and configured Fix Inventory to collect your AWS resources.

Directions​

  1. Execute the following search command in Fix Inventory Shell:

    > search is(aws_cloud_trail) and trail_kms_key_id==null
    ​kind=aws_cloud_trail, ..., region=fixinventory-poweruser
    ​kind=aws_cloud_trail, ..., account=poweruser-team

  2. Pipe the search command into the dump command:

    > search is(aws_cloud_trail) and trail_kms_key_id==null | dump
    ​reported:
    ​  id: /aws/cloudtrail/123
    ​  name: some-name
    ​  ctime: '2022-12-05T22:53:14Z'
    ​  kind: aws_cloud_trail
    ​  age: 2mo28d

    The command output will list the details of all non-compliant aws_cloud_trail resources.

Remediation​

  • Create and manage the CMK encryption keys.
  • Use a single CMK to encrypt and decrypt log files for multiple accounts across all regions.
  • Control who can use your key for encrypting and decrypting CloudTrail log files.
  • Assign permissions for the key to the users.
note

Please refer to the AWS CloudTrail documentation for details.

Further Reading​