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Carwings JSON API Protocol

This protocol is a much simpler interface to the Carwings telematics information. The original protocol was an XML SOAP API and was a bit of a pain to work with. Requests to this protocol began failing in February 2016 signaling its decomissioning.

I have noticed that the API seems to be a bit inconsistent and vary in the data that makes any difference to the request, and in what data is returned for common responses. Please submit a pull-request with changes found during your empirical usage.

Every operation is executed as a HTTP POST request and responds with a JSON document. Parameters for the operation are x-www-form-urlencoded in the body.

The only operation that requires any kind of credentials is the User Login operation. All other operations take a custom_sessionid that is negotiate during a two-phase authentication exchange.

All of the response documents have a message and status property to signal operation success/failure. The status is a numerical value that is 200 on success, and message is (usually) a string that is success for successful operations. For unsuccessful operations the error message is contained in the ErrorMessage field.

The base URI for the API operations is https://gdcportalgw.its-mo.com/gworchest_160803A/gdc/.

Long Polled Operations

Operations that dispatch a request to the vehicle follow a long polling pattern. There are a pair of operations for these types of requests. The first is an operation to initiate the vehicle request. The result of these initiating operations is a resultKey. The value of this key can be used as a parameter to the matching *Result operation to poll for the operation completion and result.

These result operations return a document that contains a responseFlag property. When this property comes back 0, the vehicle response is still pending. When it returns 1, the vehicle request has been completed and the document contains the operation result properties.

Security Compromise

In February of 2016 it was found that the API actually ignored the assumed requirement to privide the proper DCMID in requests after the initial login. This resulted in the ability to send operations to any target vehicle having only its VIN. An update was subsequently released in March of the same year that resulted in the auth scheme described in the current version of this document.

In the update, the base path of the URI for API calls was changed from orchestration_1111 to gworchest_0307C. This is most likely a versioning scheme similar to other JSON APIs that use something like v1 to v2 to allow concurrent usage of different API versions. In the case of the Carwings API, the old version has been completely replaced by this new revision.

Finally, in the face of this compromise was that the requests were changed to use the HTTP POST method and data is x-www-form-urlencoded when previously they exclusively used GET with querystring parameters.

User Login

Security Changes

After the security flaw discovery there was a major change to the way API auth works. I think it is interesting to consider the changes that were made in the name of security.

Even though the API interactions are already covered by transport security, Nissan felt the need to obfuscate the user password using a two-phase exchange that involves encrypting the user's password using a key provide in phase 1.

Since the encryption key is provided in the same communication channel, this provides no additional security against MITM, downgrade, or data compromise attacks. As such I think we can only consider this particular dance to be, at the best, obfuscation.

However, the fact that it now seems to use unique cryptographically secure session keys and has moved to using POST are both definite wins for the security of the Carwings API and all of our vehicles.

The authentication scheme used by the API happens in two phases.

In addition to the steps described here, the auth system also requires an additional parameter to be included in all requests. This parameter currently has the value: initial_app_strings=geORNtsZe5I4lRGjG9GZiA.

Phase 1

The first phase of the exchange is to call the InitialApp operation and retrieve the baseprm value from the response. This value is the encryption key used to derive credentials for phase 2.

operation: InitialApp.php data: initial_app_strings=geORNtsZe5I4lRGjG9GZiA'

response:

{
    "status":200,
    "message":"success",
    "baseprm":"uyI5Dj9g8VCOFDnBRUbr3g"
}

NB: This operation's response currently specifies an incorrect Content-Type: text/html; charset=UTF8.

Phase 2

To call the phase 2 UserLoginRequest operation, the baseprm value is used to encrypt the user's password with Blowfish ECB encryption and PKCS5 padding. The resultant ciphertext is then provided as the Password parameter of the login operation in a base64 encoded format.

The owner's profile is included in response and has a list of their vehicles, each of their VINs and DCMIDs which you'll need to make requests directed at a specific vehicle.

The response list (vehicleInfo note the lowercase "v") also includes the custom_sessionid which is used for authorization and must be included as a parameter in all subsequent requests.

operation: UserLoginRequest.php data: RegionCode=NNA&UserId=<email>&Password=<base64_cipher_password>&initial_app_strings=geORNtsZe5I4lRGjG9GZiA

response:

{
    "CustomerInfo": {
        "Country": "US",
        "Language": "en-US",
        "Nickname": "<userid>",
        "OwnerId": "<redacted>",
        "RegionCode": "NNA",
        "Timezone": "America/Denver",
        "UserId": "<userid>",
        "UserVehicleBoundDurationSec": "946771200",
        "VehicleImage": "/content/language/default/images/img/ph_car.jpg",
        "VehicleInfo": {
            "DCMID": "<dcmid>",
            "EncryptedNAVIID": "<redacted>",
            "LastDCMUseTime": "Dec 12, 2016 05:26 PM",
            "LastVehicleLoginTime": "",
            "MSN": "<redacted>",
            "NAVIID": "<redacted>",
            "SIMID": "<redacted>",
            "UserVehicleBoundTime": "2014-07-04T20:42:40Z",
            "VIN": "<vin>"
        }
    },
    "EncAuthToken": "<redacted>",
    "UserInfoRevisionNo": "2",
    "VehicleInfoList": {
        "VehicleInfo": [
            {
                "charger20066": "false",
                "nickname": "<carName>",
                "telematicsEnabled": "true",
                "vin": "<vin>"
            }
        ],
        "vehicleInfo": [
            {
                "charger20066": "false",
                "custom_sessionid": "<custom_sessionid>",
                "nickname": "<carName>",
                "telematicsEnabled": "true",
                "vin": "<vin>"
            }
        ]
    },
    "sessionId": "<redacted>",
    "status": 200,
    "vehicle": {
        "profile": {
            "dcmId": "<dcmid>",
            "encAuthToken": "<redacted>",
            "gdcPassword": "",
            "gdcUserId": "",
            "nickname": "<userid>",
            "status": "ACCEPTED",
            "statusDate": "Jul  4, 2014 12:00 AM",
            "vin": "<vin>"
        }
    }
}

Get Cached Vehicle Status

This operation returns the status information that the service currently has cached for the requested vehicle, without dispatching a status update request.

endpoint: BatteryStatusRecordsRequest.php data: RegionCode=NNA&VIN=<vin>&custom_sessionid=<custom_sessionid>

response:

{
    "BatteryStatusRecords": {
        "BatteryStatus": {
            "BatteryCapacity": "12",
            "BatteryChargingStatus": "NORMAL_CHARGING",
            "BatteryRemainingAmount": "9",
            "BatteryRemainingAmountWH": "",
            "BatteryRemainingAmountkWH": ""
        },
        "CruisingRangeAcOff": "101904.0",
        "CruisingRangeAcOn": "94184.0",
        "NotificationDateAndTime": "2016/01/08 21:26",
        "OperationDateAndTime": "Jan  8, 2016 02:26 PM",
        "OperationResult": "START",
        "PluginState": "CONNECTED",
        "TargetDate": "2016/01/08 21:26",
        "TimeRequiredToFull200_6kW": {
            "HourRequiredToFull": "2",
            "MinutesRequiredToFull": "30"
        }
    },
    "message": "success",
    "status": 200
}

Initiate Status Update

The status data retreived for a vehicle is cached by the service. Call this operation to initiate a refresh of the vehicle's status.

long-poll request Use the Status Update Result operation to poll for results.

operation: BatteryStatusCheckRequest.php data: RegionCode=NNA&VIN=<vin>&custom_sessionid=<custom_sessionid>

response:

{
    "message": "success",
    "resultKey": "<key>", // Key can be used with update result check operation
    "status": 200,
    "userId": "<email>",
    "vin": "<vin>"
}

Status Update Result

As long as the responseFlag property is 0 in the response, the update request is still awaiting a response from the vehicle. When this value comes back 1, then the document will also be filled with the vehicle status properties.

operation: BatteryStatusCheckResultRequest.php data: RegionCode=NNA&VIN=<vin>&custom_sessionid=<custom_sessionid>&&resultKey=<key>

pending response:

{
    "message": "success",
    "responseFlag": "0",
    "status": 200
}

completed response:

{
    "batteryCapacity": "12",
    "batteryDegradation": "1",
    "chargeMode": "NOT_CHARGING",
    "chargeStatus": "CT",
    "charging": "NO",
    "cruisingRangeAcOff": "18104.0",
    "cruisingRangeAcOn": "17112.0",
    "currentChargeLevel": "0",
    "message": "success",
    "operationResult": "START",
    "pluginState": "NOT_CONNECTED",
    "responseFlag": "1",
    "status": 200,
    "timeRequiredToFull": {
        "hours": "",
        "minutes": ""
    },
    "timeRequiredToFull200": {
        "hours": "",
        "minutes": ""
    },
    "timeRequiredToFull200_6kW": {
        "hours": "",
        "minutes": ""
    },
    "timeStamp": "2016-02-07 21:58:21"
}

HVAC Status

To get the status of the HVAC (Climate Control), use the following request.

operation: RemoteACRecordsRequest.php data: RegionCode=NNA&DCMID=<dcmid>&VIN=<vin>&custom_sessionid=<custom_sessionid>

Response (when Climate Control is ON):

{
	"status": 200,
	"message": "success",
	"RemoteACRecords": {
		"OperationResult": "START",
		"OperationDateAndTime": "Feb 20, 2016 05:51 PM",
		"RemoteACOperation": "START",
		"ACStartStopDateAndTime": "Feb 20, 2016 05:52 PM",
		"CruisingRangeAcOn": "65520.0",
		"CruisingRangeAcOff": "90480.0",
		"ACStartStopURL": "",
		"PluginState": "CONNECTED",
		"ACDurationBatterySec": "900",
		"ACDurationPluggedSec": "7200"
	},
	"OperationDateAndTime": ""
}

Response (when Climate Control is OFF):

{
	"status": 200,
	"message": "success",
	"RemoteACRecords": {
		"OperationResult": "START",
		"OperationDateAndTime": "Feb 20, 2016 05:54 PM",
		"RemoteACOperation": "STOP",
		"ACStartStopDateAndTime": "Feb 20, 2016 05:55 PM",
		"CruisingRangeAcOn": "68880.0",
		"CruisingRangeAcOff": "95120.0",
		"ACStartStopURL": "",
		"PluginState": "CONNECTED",
		"ACDurationBatterySec": "900",
		"ACDurationPluggedSec": "7200"
	},
	"OperationDateAndTime": ""
}

Also available: Get Climate Control Timer Settings

operation: GetScheduledACRemoteRequest.php data: RegionCode=NNA&VIN=<vin>&custom_sessionid=<custom_sessionid>&tz=America/Denver

HVAC Remote Activate

This operation sends a command to turn the HVAC system on in the car.

long-poll operation Use the HVAC Remote Activate Result operation to poll for results.

operation: ACRemoteRequest.php data: RegionCode=NNA&VIN=<vin>&custom_sessionid=<custom_sessionid>

response:

{
    "message": "success",
    "resultKey": "<key>",
    "status": 200,
    "userId": "<email>",
    "vin": "<vin>"
}

HVAC Remote Activate Result

operation: ACRemoteResult.php data: RegionCode=NNA&VIN=<vin>&custom_sessionid=<custom_sessionid>&resultKey=<key>

pending response:

{
    "message": "success",
    "responseFlag": "0",
    "status": 200
}

completed response (with battery too low to activate):

{
    "hvacStatus": "0",
    "message": "success",
    "operationResult": "NG",
    "responseFlag": "1",
    "status": 200,
    "timeStamp": "2016-02-07 21:35:34"
}

HVAC Remote Deactivate

The URLs used to turn the HVAC off:

  • Request operation: ACRemoteOffRequest.php data: RegionCode=NNA&VIN=<vin>&custom_sessionid=<custom_sessionid>

  • Long-polling result operation: ACRemoteOffResult.php data: RegionCode=NNA&VIN=<vin>&custom_sessionid=<custom_sessionid>&resultKey=<key>

Start Charging

operation: BatteryRemoteChargingRequest.php data: RegionCode=NNA&VIN=<vin>&custom_sessionid=<custom_sessionid>&tz=America/Denver&ExecuteTime=2016-02-20

Value for ExecuteTime seems to be today's date.

RegionCode

For different regions you must use the proper regionCode. For example, in Canada the region code is NCI.

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