ECR Repository should use customer managed keys to allow more control

Images in the ECR repository are encrypted by default using AWS managed encryption keys. To increase control of the encryption and control the management of factors like key rotation, use a Customer Managed Key.

Impact

Using AWS managed keys does not allow for fine grained control

Recommended Actions

Follow the appropriate remediation steps below to resolve the issue.

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---
AWSTemplateFormatVersion: "2010-09-09"
Description: A sample template
Resources:
  GoodExample:
    Type: AWS::ECR::Repository
    Properties:
      RepositoryName: "test-repository"
      ImageTagImmutability: IMMUTABLE
      ImageScanningConfiguration:
        ScanOnPush: false
      EncryptionConfiguration:
        EncryptionType: KMS
        KmsKey: "alias/ecr-key"

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resource "aws_kms_key" "ecr_kms" {
  enable_key_rotation = true
}

resource "aws_ecr_repository" "good_example" {
  name                 = "bar"
  image_tag_mutability = "MUTABLE"
  
  image_scanning_configuration {
    scan_on_push = true
  }
  
  encryption_configuration {
    encryption_type = "KMS"
    kms_key = aws_kms_key.ecr_kms.key_id
  }
}

Links

• https://docs.aws.amazon.com/AmazonECR/latest/userguide/encryption-at-rest.html