Description

EFS data should be encrypted at rest using AWS KMS (Key Management Service).

Rationale

Data should be encrypted at rest to reduce the risk of a data breach via direct access to the storage device.

Audit

From Console

1. Log in to the AWS Management Console and navigate to the Elastic File System (EFS) dashboard.
2. Select File Systems from the left navigation panel.
3. Each item on the list has a visible Encrypted field that displays the data-at-rest encryption status.
4. Validate that this field reads Encrypted for all EFS file systems in all AWS regions.

From Command Line

1. Run the describe-file-systems command using custom query filters to list the identifiers of all AWS EFS file systems currently available within the selected region:

   aws efs describe-file-systems --region {{region-name}} --output table --query 'FileSystems[*].FileSystemId'

2. The command output should return a table with the requested file system IDs.

3. Run the describe-file-systems command using the ID of the file system that you want to examine as the identifier and the necessary query filters:

   aws efs describe-file-systems --region {{region-name}} --file-system-id {{file-system-id}} --query 'FileSystems[*].Encrypted'

4. The command output should return the file system encryption status true or false. If the returned value is false, the selected AWS EFS file system is not encrypted. If the returned value is true, the selected AWS EFS file system is encrypted.

Default Value

EFS file system data is encrypted at rest by default when creating a file system via the Console. Encryption at rest is not enabled by default when creating a new file system using the AWS CLI, API, and SDKs.

References

1. https://docs.aws.amazon.com/efs/latest/ug/encryption-at-rest.html
2. https://awscli.amazonaws.com/v2/documentation/api/latest/reference/efs/index.html#efs