How to Detect Unlocked Bootloader in Android Apps

Last updated June 12, 2023 by Appdome

Learn to Detect Unlocked Bootloader in Android apps, in mobile CI/CD with a Data-Driven DevSecOps™ build system.

What is an Unlocked Bootloader ?

The Android operating system provides several security features that can help ensure that an application is running on a verified device. One of them specifically checks a device to ensure that the bootloader integrity has been maintained. An unlocked bootloader on an Android device creates state in which the device’s bootloader can been modified to allow the installation malicious firmware or operating systems.

One of Android’s primary mechanisms is the Root of Trust, a set of secure hardware and software components that form the foundation of the Android OS security model. The root of trust includes components designed to establish and maintain a chain of trust throughout the device, including the bootloader.

How does Appdome Detect an Unlocked Bootloader?

Device Attestation detects signs of a compromised environment, such as an unlocked/replaced boot loader or an unverified boot image.

If such signs are detected, Device Attestation prevents any attempt to run an Appdome-protected app on a device whose ROM is other than the one installed by the device manufacturer.

Detect Unlocked Bootloader on Android apps using Appdome

On Appdome, follow these 3 simple steps to create self-defending Android Apps that Detect Unlocked Bootloader 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
    4. Detect Unlocked Bootloader Compatible With: Java, JS, C++, C#, Kotlin, Flutter, React Native, Unity, Xamarin, Cordova and more
  2. Build the feature: Detect Unlocked Bootloader .

    1. Building Detect Unlocked Bootloader by using Appdome’s DEV-API:

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

        Figure 1: Fusion Set that will contain the Detect Unlocked Bootloader 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 Detect Unlocked Bootloader feature via Appdome Console, to add the Detect Unlocked Bootloader 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 Detect Unlocked Bootloader feature via Appdome Console

      To build the Detect Unlocked Bootloader 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) Detect Unlocked Bootloader , as shown below.
        If needed, Customize the Threat Notification to be displayed to the mobile end-user in a standard OS dialog notification when Appdome Detects Unlocked Bootloader . Detect Unlocked Bootloader  option

        Figure 3: Detect Unlocked Bootloader option
        Note: The App Compromise Notification contains an easy to follow default remediation path for the mobile app end user. You can customize this message as required to achieve brand specific support, workflow or other messaging.

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

        Fusion Set applied Detect Unlocked Bootloader

        Figure 4: Fusion Set that displays the newly added Detect Unlocked Bootloader protection

      4. Select the Threat-Event™ in-app mobile Threat Defense and Intelligence policy for Detect Unlocked Bootloader :
        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 Detect Unlocked Bootloader .

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

          When this setting is used, Appdome detects if the bootloader has been unlocked on an Android device on which the protected app is running 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 Detect Unlocked Bootloader Intelligence and Control in Mobile Apps.

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

          When this setting is used, Appdome detects and defends against Unlocked Bootloader (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 Detect Unlocked Bootloader Intelligence and Control in Mobile Apps.

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

    After building Detect Unlocked Bootloader , Appdome generates a Certified Secure™ certificate to guarantee that the Detect Unlocked Bootloader protection has been added and is protecting the app. To verify that the Detect Unlocked Bootloader protection has been added to the mobile app, locate the protection in the Certified Secure™ certificate as shown below: Detect Unlocked Bootloader  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 Detect Unlocked Bootloader has been added to each Android app. Certified Secure provides instant and in-line DevSecOps compliance certification that Detect Unlocked Bootloader and other mobile app security features are in each build of the mobile app

Using Threat-Events™ for Unlocked Bootloader Intelligence and Control in Android Apps

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

The specifications and options for Threat-Events™ for Unlocked Bootloader are:

Threat-Event™ Elements Detect Unlocked Bootloader Method Detail
Appdome Feature Name Detect Unlocked Bootloader
Threat-Event Mode
OFF, IN-APP DEFENSE Appdome detects, defends and notifies user (standard OS dialog) using customizable messaging.
ON, IN-APP DETECTION 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 Detecting Unlocked Bootloader Threat-Event™
Threat-Event NAME DetectUnlockedBootloader
Threat-Event DATA reasonData
Threat-Event CODE reasonCode
Threat-Event REF 6801
Threat-Event SCORE
currentThreatEventScore Current Threat-Event score
threatEventsScore Total Threat-events score
Threat-Event Context Keys
message Message displayed for the user on event
externalID The external ID of the event which can be listened via Threat Events
osVersion OS version of the current device
deviceModel Current device model
deviceManufacturer The manufacturer of the current device
fusedAppToken The task ID of the Appdome fusion of the currently running app
kernelInfo Info about the kernel: system name, node name, release, version and machine.
carrierPlmn PLMN of the device
deviceID Current device ID
reasonCode Reason code of the occured event
buildDate Appdome fusion date of the current application
devicePlatform OS name of the current device
carrierName Carrier name of the current device
updatedOSVersion Is the OS version up to date
deviceBrand Brand of the device
deviceBoard Board of the device
buildUser Build user
buildHost Build host
sdkVersion Sdk version
timeZone Time zone
deviceFaceDown Is the device face down
locationLong Location long
locationLat Location lat
locationState Location state
wifiSsid Wifi SSID
wifiSsidPermissionStatus Wifi SSID permission status

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 Unlocked Bootloader is detected.

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

Prerequisites to Using Detect Unlocked Bootloader :

To use Appdome’s mobile app security build system to Detect Unlocked Bootloader , you’ll need:

Using Appdome, there are no development or coding prerequisites to build secured Android Apps by using Detect Unlocked Bootloader . 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 Detect Unlocked Bootloader

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.

Related Articles:

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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