How to Detect OS Remount in Android Apps

Last updated December 18, 2023 by Appdome

This Knowledge Base article describes how to use Appdome’s AI/ML in your CI/CD pipeline to continuously deliver plugins that Detect OS Remount in Android apps.

What is OS Remount?

In Android, OS Remount is used for changing the read/write permissions of the device’s file system. By default, Android mounts the file system as read-only to prevent accidental modification or deletion of critical system files. Nevertheless, in certain situations, you may want to use OS Remount for modifying or updating system files, such as when applying a software update or installing a custom ROM. Appdome’s Detect OS Remount protection ensures that OS remounts cannot be used for malicious reasons.

Why Should Developer Prevent OS Remount?

Preventing the file system from remounting on an Android device may be necessary in certain situations, such as when you want to prevent unauthorized changes to system files, or when you want to enforce a higher level of security on the device.
Malware can abuse the remount feature and potentially lead to various security threats, such as:
  • Data theft
    Attackers can use the remount feature to modify an Android device’s system files and steal sensitive information such as passwords and credit card numbers.
  • Remote access
    By injecting malware into the system files of an Android device, attackers can gain remote access and control of the device. By gaining remote control, attackers can perform malicious actions such as installing additional malware or stealing data.
  • Rooting the device
    If attackers gain access to the file system of an Android device, they can use the remount feature to gain root access. With root access, attackers have complete control over the device and can perform a variety of malicious actions.

Prerequisites for Using Appdome's Detect OS Remount Plugins:

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

How to Implement Detect OS Remount in Android Apps Using Appdome

On Appdome, follow these 3 simple steps to create self-defending Android Apps that Detect OS Remount without an SDK or gateway:

  1. Designate the Mobile App to be protected.

    1. Upload an app via the Appdome Mobile Defense platform GUI or via Appdome’s DEV-API or CI/CD Plugins.

    2. Android Formats: .apk or .aab
    3. Detect OS Remount is compatible with: Java, JS, C++, C#, Kotlin, Flutter, React Native, Unity, Xamarin, Cordova and other Android apps.
  2. Select the defense: Detect OS Remount.

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

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

      2. Follow the steps in Sections 2.2-2.2.2 of this article to add the Detect OS Remount feature to your Fusion Set via the Appdome Console.

      3. When you select the Detect OS Remount you'll notice that the Fusion Set you created in step 2.1 now bears the icon of the protection category that contains Detect OS Remount.

        Fusion Set applied Detect OS Remount

        Figure 2: Fusion Set that displays the newly added Detect OS Remount protection
        Note: Annotating the Fusion Set to identify the protection(s) selected is optional only (not mandatory).

      4. Open the Fusion Set Detail Summary by clicking the “...” symbol on the far-right corner of the Fusion Set. Copy the Fusion Set ID from the Fusion Set Detail Summary (as shown below): fusion Set Detail Summary image

        Figure 3: Fusion Set Detail Summary

      5. Follow the instructions below to use the Fusion Set ID inside any standard mobile DevOps or CI/CD toolkit like Bitrise, Jenkins, Travis, Team City, Circle CI or other system:
        1. Refer to the Appdome API Reference Guide for API building instructions.
        2. Look for sample APIs in Appdome’s GitHub Repository.
    1. Add the Detect OS Remount feature to your security template.

      1. Navigate to Build > Anti Fraud tab > Mobile Malware Prevention section in the Appdome Console.
      2. Toggle On > Detect OS Remount.

        (a) Choose to monitor this attack vector by checking the Threat Events checkbox associated with Detect OS Remount as shown below.

        (b) To receive mobile Threat Monitoring, check the ThreatScope™ box as shown below. For more details, see our knowledge base article on ThreatScope™ Mobile XDR.
        Detect OS Remount option

        Figure 4: Selecting Detect OS Remount

        Note: The Appdome Platform displays the Mobile Operation Systems supported by each defense in real-time. For more details, see our OS Support Policy KB.

      3. Select the Threat-Event™ in-app mobile Threat Defense and Intelligence policy for Detect OS Remount:
        1. Threat-Events™ OFF > In-App Defense

          If the Threat-Events™ setting is not selected. Appdome will detect and defend the user and app by enforcing OS Remount.

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

          When this setting is used, Appdome detects OS remount 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™ to Detect OS RemountDetect Intelligence and Control in Mobile Apps.

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

          When this setting is used, Appdome detects and defends against OS Remount (same as Appdome Enforce) and passes Appdome’s Threat-Event™ attack intelligence to 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 OS RemountDetect Intelligence and Control in Mobile Apps.

      4. Configure the User Experience Options for Detect OS Remount:
        With Threat-Events™ OFF, Appdome provides several user experience options for mobile brands and developers.
        1. App Compromise Notification: Customize the pop-up or toast Appdome uses to notify the user when a threat is present while using the protected mobile app.
        2. Short message Option. This is available for mobile devices that allow a banner notification for security events.
        3. Localized Message Option. Allows Appdome users to support global languages in security notifications.

          Localized Message

          Figure 5: Default User Experience Options for Appdome’s OS Remount

        4. Detect OS Remount Threat Code™. Appdome uses AI/ML to generate a unique code each time Detect OS Remount is triggered by an active threat on the mobile device. Use the code in Appdome Threat Resolution Center™ to help end users identify, find and resolve active threats on the personal mobile devices.
    2. Initiate the build command either by clicking Build My App at the bottom of the Build Workflow (shown in Figure 4) or via your CI/CD as described in Section 2.1.4.
    Congratulations!  The Detect OS Remount protection is now added to the mobile app
  3. Certify the Detect OS Remount feature in Android Apps

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

    Figure 6: 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 OS Remount has been added to each Android app. Certified Secure provides instant and in-line DevSecOps compliance certification that Detect OS Remount and other mobile app security features are in each build of the mobile app.

Using Threat-Events™ for OS Remount Intelligence and Control in Android Apps

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

The specifications and options for Threat-Events™ for OS Remount are:

Threat-Event™ Elements Detect OS Remount Method Detail
Appdome Feature Name Detect OS Remount
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 OS Remount Threat-Event™
Threat-Event NAME RewritableRoot
Threat-Event DATA reasonData
Threat-Event CODE reasonCode
Threat-Event REF 554
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
failSafeEnforce Timed enforcement against the identified threat
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. Only available for Android devices.
deviceID Current device ID
reasonCode Reason code of the occurred event
buildDate Appdome fusion date of the current application
devicePlatform OS name of the current device
carrierName Carrier name of the current device. Only available for Android.
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 longitude conditioned by location permission
locationLat Location latitude conditioned by location permission
locationState Location state conditioned by location permission
wifiSsid Wifi SSID
wifiSsidPermissionStatus Wifi SSID permission status
threatCode The last six characters of the threat code specify the OS, allowing the Threat Resolution Center to address the attack on the affected device.

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 OS Remount is detected.


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


Important! Replace all placeholder instances of <Context Key> with the specific name of your threat event context key across all language examples. This is crucial to ensure your code functions correctly with the intended event data. For example, The <Context Key> could be the message, externalID, OS Version, reason code, etc.



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

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:

Related Articles:

How Do I Learn More?

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

Thank you!

Thanks for visiting Appdome! Our mission is to secure every app on the planet by making mobile app security easy. We hope we’re living up to the mission with your project.

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