How to Harden Google SafetyNet Attestation in Android Apps

Last updated August 11, 2022 by Appdome

Learn to Add SafetyNet Attestation in Android apps, in mobile CI/CD with a Data-Driven DevSecOps™ build system.

What is Google SafetyNet Attestation API?

SafetyNet is a suite of features offered by Google to ensure and maintain the safety and integrity of all Android applications stored in the Google Play Store. The protection that SafetyNet provides for sensitive information stored within an application helps safekeeping the device integrity, as well as enhancing user trust. Users can trust Google SafetyNet, as it is not connected to any device manufacturer but is part of Google Play Services.

SafetyNet Attestation API is an anti-abuse API that allows app developers to assess the Android device on which their app is running. By providing a cryptographically signed attestation, assessing the device’s integrity, the API can be used for helping you determine whether your servers are interacting with your genuine app, running on a real Android device.

How does Appdome implement the SafetyNet Device Attestation API ?

Appdome implemented the SafetyNet Device Attestation API so that a SafetyNet Device Audit can be performed by Appdome on behalf of our customers. To use SafetyNet with Appdome, the Appdome admin/developer needs to insert their API key. Appdome will then perform the Attestation audit and sends the results back as a Threat Event.
For further details, see this article: https://developer.android.com/training/safetynet/attestation

Adding SafetyNet Attestation on Android apps by Using Appdome

On Appdome, follow these 3 simple steps to create self-defending Android Apps that Add SafetyNet Attestation without an SDK or gateway:

  1. Upload the Mobile App to Appdome.

    1. Upload an app to Appdome’s Mobile App Security Build System

    2. Upload Method: Appdome Console or DEV-API
    3. Android Formats: .apk or .aab
  2. Build the Protection: SafetyNet Attestation .

    1. Building SafetyNet Attestation by using Appdome’s DEV-API:

      1. Create and name the Fusion Set (security template) that will contain the SafetyNet Attestation feature as shown below:
      2. fusion set that contains SafetyNet Attestation

        Figure 1: Fusion Set that will contain the SafetyNet Attestation feature
        Note: Naming the Fusion Set to correspond to the protection(s) selected is for illustration purposes only (not required).

      3. Follow the steps in Sections 2.2.1-2.2.2 of this article, Building the SafetyNet Attestation feature via Appdome Console, to add the SafetyNet Attestation feature to this Fusion Set.

      4. Open the Fusion Set Detail Summary by clicking the “...” symbol on the far-right corner of the Fusion Set, as shown in Figure 1 above, and get the Fusion Set ID from the Fusion Set Detail Summary (as shown below): fusion Set Detail Summary image

        Figure 2: Fusion Set Detail Summary
        Note: Annotating the Fusion Set to identify the protection(s) selected is optional only (not mandatory).

      5. Follow the instructions below to use the Fusion Set ID inside any standard mobile DevOps or CI/CD toolkit like Bitrise, App Center, Jenkins, Travis, Team City, Cirlce CI or other system:
        1. Build an API for the app – for instructions, see the tasks under Appdome API Reference Guide
        2. Look for sample APIs in Appdome’s GitHub Repository
    2. Building the SafetyNet Attestation feature via Appdome Console

      To build the SafetyNet Attestation protection by using Appdome Console, follow the instructions below.

      1. Where: Inside the Appdome Console, go to Build > Anti Fraud Tab > Mobile Malware Prevention section
      2. How: Toggle (turn ON) SafetyNet Attestation , as shown below. SafetyNet Attestation  option

        Figure 3: Add SafetyNet Attestation option

      3. When you select the SafetyNet Attestation you'll notice that your Fusion Set you created in step 2.1.1 now bears the icon of the protection category that contains SafetyNet Attestation

        Fusion Set applied SafetyNet Attestation

        Figure 4: Fusion Set that displays the newly added SafetyNet Attestation protection

      4. Select the Threat-Event™ in-app mobile Threat Defense and Intelligence policy for SafetyNet Attestation :
        1. Threat-Events™ OFF > In-App Defense

          If the Threat-Events™ setting is cleared (not selected). Appdome will detect and defend the user and app by enforcing Add SafetyNet Attestation .

        2. Threat-Events™ ON > In-App Detection

          When this setting is used, Appdome detects an integrity issue in the device’s software or hardware environment and passes Appdome’s Threat-Event™ attack intelligence to the app’s business logic for processing, enforcement, and user notification. For more information on consuming and using Appdome Threat-Events™ in the app, see section Using Threat-Events™ for SafetyNet Attestation Intelligence and Control in Mobile Apps.

        3. Threat-Events™ ON > In-App Defense

          When this setting is used, Appdome detects and defends against SafetyNet Attestation (same as Appdome Enforce) and passes Appdome’s Threat-Event™ attack intelligence the app’s business logic for processing. For more information on consuming and using Appdome Threat-Events™ in the app, see section Using Threat-Events™ for SafetyNet Attestation Intelligence and Control in Mobile Apps.

      5. Extra Configuration with SafetyNet Attestation :
        1. Android Device Verification API Key

          Provide your unique Android Device Verification API Key from your Google APIs Console.

      6. Click Build My App at the bottom of the Build Workflow (shown in Figure 3).
    Congratulations!  The SafetyNet Attestation protection is now added to the mobile app
  3. Certify the SafetyNet Attestation feature in Android Apps.

    After building SafetyNet Attestation , Appdome generates a Certified Secure™ certificate to guarantee that the SafetyNet Attestation protection has been added and is protecting the app. To verify that the SafetyNet Attestation protection has been added to the mobile app, locate the protection in the Certified Secure™ certificate as shown below: SafetyNet Attestation  shown in Certificate secure

    Figure 5: Certified Secure™ certificate

    Each Certified Secure™ certificate provides DevOps and DevSecOps organizations the entire workflow summary, audit trail of each build, and proof of protection that SafetyNet Attestation has been added to each Android app. Certified Secure provides instant and in-line DevSecOps compliance certification that SafetyNet Attestation and other mobile app security features are in each build of the mobile app

Using Threat-Events™ for SafetyNet Attestation Intelligence and Control in Android Apps

Appdome Threat-Events™ provides consumable in-app mobile app attack intelligence and defense control when SafetyNet Attestation is detected. To consume and use Threat-Events™ for SafetyNet Attestation in Android Apps, use registerReceiver in the Application OnCreate, and the code samples for Threat-Events™ for SafetyNet Attestation shown below.

The specifications and options for Threat-Events™ for SafetyNet Attestation are:

Threat-Event™ Elements Add SafetyNet Attestation Method Detail
Appdome Feature Name SafetyNet Attestation
Threat-Event Mode
OFF, IN-APP DEFENSE Appdome detects, defends and notifies user (standard OS dialog) using customizable messaging.
ON, IN-APP DETECTON Appdome detects the attack or threat and passes the event in a standard format to the app for processing (app chooses how and when to enforce).
ON, IN-APP DEFENSE Uses Appdome Enforce mode for any attack or threat and passes the event in a standard format to the app for processing (gather intel on attacks and threats without losing any protection).
Certified Secure™ Threat Event Check
Visible in ThreatScope™
Developer Parameters for Adding SafetyNet Attestation Threat-Event™
Threat-Event NAME SafetyNetAttestationFailed
Threat-Event DATA reasonData
Threat-Event CODE reasonCode
Threat-Event REF 6923
Threat-Event SCORE
currentThreatEventScore Current Threat-Event score
threatEventsScore Total Threat-events score
Threat-Event Context Keys
messageMessage displayed for the user on event
externalIDThe external ID of the event which can be listened via Threat Events
osVersionOS version of the current device
deviceModelCurrent device model
deviceManufacturerThe manufacturer of the current device
fusedAppTokenThe task ID of the Appdome fusion of the currently running app
kernelInfoInfo about the kernel: system name, node name, release, version and machine.
carrierPlmnPLMN of the device
deviceIDCurrent device ID
reasonCodeReason code of the occured event
buildDateAppdome fusion date of the current application
devicePlatformOS name of the current device
carrierNameCarrier name of the current device
updatedOSVersionIs the OS version up to date
deviceBrandBrand of the device
deviceBoardBoard of the device
buildUserBuild user
buildHostBuild host
sdkVersionSdk version
timeZoneTime zone
deviceFaceDownIs the device face down
locationLongLocation long
locationLatLocation lat
locationStateLocation state
wifiSsidWifi SSID
wifiSsidPermissionStatusWifi SSID permission status
reasonThe advice and actions Google SafetyNet suggests upon failed attestation response from the SafetyNet API
ctsProfileMatchIs the profile of the device running your app matches the profile of a device that has passed Android compatibility testing and has been approved as a Google-certified Android device
basicIntegrityIf the check passes, the device running your app likely wasn't tampered with
evaluationTypeTypes of measurements that contributed to the current API response

With Threat-Events™ enabled (turned ON), Android developers can get detailed attack intelligence and granular defense control in Android applications and create amazing user experiences for all mobile end users when SafetyNet Attestation is detected.

The following is a code sample for native Android apps, which uses all values in the specification above for SafetyNet Attestation :

Prerequisites to Using SafetyNet Attestation :

To use Appdome’s mobile app security build system to Add SafetyNet Attestation , you’ll need:

Using Appdome, there are no development or coding prerequisites to build secured Apps by using SafetyNet Attestation . There is no SDK and no library to code or implement in the app and no gateway to deploy in your network. All protections are built into each app and the resulting app is self-defending and self-protecting.

Releasing and Publishing Mobile Apps with SafetyNet Attestation

After successfully securing your app by using Appdome, there are several available options to complete your project, depending on your app lifecycle or workflow. These include:

All apps protected by Appdome are fully compatible with any public app store, including Apple App Store, Google Play, Huawei App Gallery and more.

Protections Similar to SafetyNet Attestation

Here are a few related resources:

If you have any questions, please send them our way at support.appdome.com or via the chat window on the Appdome platform.

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