Understanding AWS sign-in events for smart card users

AWS CloudTrail logs successful and unsuccessful sign-in events for smart card users. This includes sign-in events that are captured each time a user is prompted to solve a specific credential challenge or factor, as well as the status of that particular credential verification request. A user is signed in only after completing all required credential challenges, which results in a UserAuthentication event being logged.

The following table captures each of the sign-in CloudTrail event names and their purposes.

Event name	Event purpose
CredentialChallenge	Notifies that AWS sign-in has requested that the user solve a specific credential challenge and specifies the CredentialType that is required (for example, SMARTCARD).
CredentialVerification	Notifies that the user has attempted to solve a specific CredentialChallenge request, and specifies whether that credential has succeeded or failed.
UserAuthentication	Notifies that all authentication requirements that the user was challenged with have been successfully completed and that the user was successfully signed in. When users fail to successfully complete the required credential challenges, no UserAuthentication event is logged.

The following table captures additional useful event data fields contained within specific sign-in CloudTrail events.

Event name	Event purpose	Sign-in event applicability	Example values
AuthWorkflowID	Correlates all events emitted across an entire sign-in sequence. For each user sign-in, multiple events can be emitted by AWS sign-in.	CredentialChallenge, CredentialVerification, UserAuthentication	"AuthWorkflowID": "9de74b32-8362-4a01-a524-de21df59fd83"
CredentialType	Notifies that the user has attempted to solve a specific CredentialChallenge request and specifies whether that credential has succeeded or failed.	CredentialChallenge, CredentialVerification, UserAuthentication	CredentialType": "SMARTCARD" (possible values today: SMARTCARD)
LoginTo	Notifies that all authentication requirements that the user was challenged with have been successfully completed and that the user was successfully signed in. When users fail to successfully complete the required credential challenges, no UserAuthentication event is logged.	UserAuthentication	"LoginTo": "https://skylight.local“

Example events for AWS sign-in scenarios

The following examples show the expected sequence of CloudTrail events for different sign-in scenarios.

Successful sign-in when authenticating with smart card

The following sequence of events captures an example of a successful smart card sign-in.

CredentialChallenge

{
    "eventVersion": "1.08",
    "userIdentity": {
        "type": "Unknown",
        "principalId": "509318101470",
        "arn": "",
        "accountId": "509318101470",
        "accessKeyId": ""
    },
    "eventTime": "2021-07-30T17:23:29Z",
    "eventSource": "signin.amazonaws.com",
    "eventName": "CredentialChallenge", 
    "awsRegion": "us-east-1", 
    "sourceIPAddress": "AWS Internal", 
    "userAgent": "Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/91.0.4472.164 Safari/537.36",
    "requestParameters": null,
    "responseElements": null,
    "additionalEventData": {
        "AuthWorkflowID": "6602f256-3b76-4977-96dc-306a7283269e",
        "CredentialType": "SMARTCARD"
    },
    "requestID": "65551a6d-654a-4be8-90b5-bbfef7187d3a",
    "eventID": "fb603838-f119-4304-9fdc-c0f947a82116",
    "readOnly": false,
    "eventType": "AwsServiceEvent",
    "managementEvent": true,
    "eventCategory": "Management", 
    "recipientAccountId": "509318101470", 
    "serviceEventDetails": {
        CredentialChallenge": "Success"
    }
}
                            

Successful CredentialVerification

{
    "eventVersion": "1.08",
    "userIdentity": {
        "type": "Unknown",
        "principalId": "509318101470",
        "arn": "",
        "accountId": "509318101470",
        "accessKeyId": ""
    },
    "eventTime": "2021-07-30T17:23:39Z",
    "eventSource": "signin.amazonaws.com",
    "eventName": "CredentialVerification",
    "awsRegion": "us-east-1",
    "sourceIPAddress": "AWS Internal",
    "userAgent": "Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/91.0.4472.164 Safari/537.36",
    "requestParameters": null,
    "responseElements": null,
    "additionalEventData": {
        "AuthWorkflowID": "6602f256-3b76-4977-96dc-306a7283269e",
        "CredentialType": "SMARTCARD"
    },
    "requestID": "81869203-1404-4bf2-a1a4-3d30aa08d8d5",
    "eventID": "84c0a2ff-413f-4d0f-9108-f72c90a41b6c",
    "readOnly": false,
    "eventType": "AwsServiceEvent",
    "managementEvent": true,
    "eventCategory": "Management",
    "recipientAccountId": "509318101470",
    "serviceEventDetails": {
        CredentialVerification": "Success"
    }
}
                            

Successful UserAuthentication

{
    "eventVersion": "1.08",
    "userIdentity": {
        "type": "Unknown",
        "principalId": "509318101470",
        "arn": "",
        "accountId": "509318101470",
        "accessKeyId": ""
    },
    "eventTime": "2021-07-30T17:23:39Z",
    "eventSource": "signin.amazonaws.com",
    "eventName": "UserAuthentication", 
    "awsRegion": "us-east-1", 
    "sourceIPAddress": "AWS Internal", 
    "userAgent": "Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/91.0.4472.164 Safari/537.36",
    "requestParameters": null,
    "responseElements": null,
    "additionalEventData": {
        "AuthWorkflowID": "6602f256-3b76-4977-96dc-306a7283269e", 
        "LoginTo": "https://skylight.local", 
        "CredentialType": "SMARTCARD"
    },
    "requestID": "81869203-1404-4bf2-a1a4-3d30aa08d8d5", 
    "eventID": "acc0dba8-8e8b-414b-a52d-6b7cd51d38f6", 
    "readOnly": false,
    "eventType": "AwsServiceEvent", 
    "managementEvent": true,
    "eventCategory": "Management", 
    "recipientAccountId": "509318101470", 
    "serviceEventDetails": {
        UserAuthentication": "Success"
    }
}
                            

Failed sign-in when authenticating with only a smart card

The following sequence of events captures an example of failed smart card sign-in.

CredentialChallenge

{
    "eventVersion": "1.08",
    "userIdentity": {
        "type": "Unknown",
        "principalId": "509318101470",
        "arn": "",
        "accountId": "509318101470",
        "accessKeyId": ""
    },
    "eventTime": "2021-07-30T17:23:06Z",
    "eventSource": "signin.amazonaws.com",
    "eventName": "CredentialChallenge", 
    "awaRegion": "us-east-1", 
    "sourceIPAddress": "AWS Internal", 
    "userAgent": "Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/91.0.4472.164 Safari/537.36",
    "requestParameters": null,
    "responseElements": null,
    "additionalEventData": {
        "AuthWorkflowID": "73dfd26b-f812-4bd2-82e9-0b2abb358cdb",
        "CredentialType": "SMARTCARD"
    },
    "requestID": "73eb499d-91a8-4c18-9c5d-281fd45ab50a",
    "eventID": "f30a50ec-71cf-415a-a5ab-e287edc800da",
    "readOnly": false,
    "eventType": "AwsServiceEvent",
    "managementEvent": true,
    "eventCategory": "Management", 
    "recipientAccountId": "509318101470", 
    "serviceEventDetails": {
        CredentialChallenge": "Success"
    }
}
                            

Failed CredentialVerification

{
    "eventVersion": "1.08",
    "userIdentity": {
        "type": "Unknown",
        "principalId": "509318101470",
        "arn": "",
        "accountId": "509318101470",
        "accessKeyId": ""
    },
    "eventTime": "2021-07-30T17:23:13Z",
    "eventSource": "signin.amazonaws.com",
    "eventName": "CredentialVerification",
    "awsRegion": "us-east-1",
    "sourceIPAddress": "AWS Internal",
    "userAgent": "Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/91.0.4472.164 Safari/537.36",
    "requestParameters": null,
    "responseElements": null,
    "additionalEventData": {
        "AuthWorkflowID": "73dfd26b-f812-4bd2-82e9-0b2abb358cdb",
        "CredentialType": "SMARTCARD"
    },
    "requestID": "051ca316-0b0d-4d38-940b-5fe5794fda03",
    "eventID": "4e6fbfc7-0479-48da-b7dc-e875155a8177",
    "readOnly": false,
    "eventType": "AwsServiceEvent",
    "managementEvent": true,
    "eventCategory": "Management", 
    "recipientAccountId": "509318101470", 
    "serviceEventDetails": {
        CredentialVerification": "Failure"
    }
}