Finding aliases in AWS CloudTrail logs

You can use an alias to represent an AWS KMS key in an AWS KMS API operation. When you do, the alias and the key ARN of the KMS key are recorded in the AWS CloudTrail log entry for the event. The alias appears in the requestParameters field. The key ARN appears in the resources field. This is true even when an AWS service uses an AWS managed key in your account.

For example, the following GenerateDataKey request uses the project-key alias to represent a KMS key.

$ aws kms generate-data-key --key-id alias/project-key --key-spec AES_256

When this request is recorded in the CloudTrail log, the log entry includes both the alias and the key ARN of the actual KMS key that was used.

{
    "eventVersion": "1.05",
    "userIdentity": {
        "type": "IAMUser",
        "principalId": "ABCDE",
        "arn": "arn:aws:iam::111122223333:role/ProjectDev",
        "accountId": "111122223333",
        "accessKeyId": "FFHIJ",
        "userName": "example-dev"
    },
    "eventTime": "2020-06-29T23:36:41Z",
    "eventSource": "kms.amazonaws.com",
    "eventName": "GenerateDataKey",
    "awsRegion": "us-west-2",
    "sourceIPAddress": "205.205.123.000",
    "userAgent": "aws-cli/1.18.89 Python/3.6.10 Linux/4.9.217-0.1.ac.205.84.332.metal1.x86_64 botocore/1.17.12",
    "requestParameters": {
        "keyId": "alias/project-key",
        "keySpec": "AES_256"
    },
    "responseElements": null,
    "requestID": "d93f57f5-d4c5-4bab-8139-5a1f7824a363",
    "eventID": "d63001e2-dbc6-4aae-90cb-e5370aca7125",
    "readOnly": true,
    "resources": [
        {
            "accountId": "111122223333",
            "type": "AWS::KMS::Key",
            "ARN": "arn:aws:kms:us-west-2:111122223333:key/1234abcd-12ab-34cd-56ef-1234567890ab"
        }
    ],
    "eventType": "AwsApiCall",
    "recipientAccountId": "111122223333"
}

For details about logging AWS KMS operations in CloudTrail logs, see Logging AWS KMS API calls with AWS CloudTrail.