externalId

The external ID to specify in the trust policy for the IAM role to assume when retrieving sensitive data from affected S3 objects (roleName). This value is null if the value for retrievalMode is CALLER_CREDENTIALS.

This ID is a unique alphanumeric string that Amazon Macie generates automatically after you configure it to assume an IAM role. For a Macie administrator to retrieve sensitive data from an affected S3 object for a member account, the trust policy for the role in the member account must include an sts:ExternalId condition that requires this ID.