How to Detect KernelSU

Last updated December 7, 2023 by Appdome

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

What is KernelSU?

KernelSU is a robust technique for rooting Android devices by working directly with the kernel. This approach grants root access to user space apps within the kernel space, providing extensive privileges not available in other rooting methods. This uniqueness gives KernelSU its considerable power. Within the kernel space, it becomes possible to intercept system calls, access various types of memory (both physical and virtual), utilize internal Android kernel tools, and access a range of advanced features. Notably, KernelSU accomplishes all this while remaining hidden because regular user-space apps cannot reach the kernel space where KernelSU operates.

Why Blocking KernelSU is Crucial for App Security?

Understanding the potential risks associated with the KernelSU root solution requires delving into why blocking its use is critical in enhancing app security. KernelSU, like Magisk, raises substantial security concerns that should not be taken lightly. When employed on a rooted Android device alongside your app, it exposes vulnerabilities that malicious actors can exploit. As a result, it is essential to emphasize the significance of integrating protective measures within your app to counter these threats effectively. KernelSU grants root access to user space applications within the kernel space, elevating privileges to an unprecedented level. This heightened access exposes apps to potential security breaches and enables utilizing tools and functionalities typically unavailable through other rooting methods.
Such privileges create an environment where unauthorized access, system manipulation, and data breaches become feasible. Furthermore, the very nature of KernelSU’s kernel-based root access makes it difficult to detect and counteract. Regular user-space applications lack the capability to interact with kernel space, where KernelSU operates, rendering them powerless in thwarting its actions. This stealthy operation allows KernelSU to bypass traditional security mechanisms, making it a preferred choice for cybercriminals seeking to compromise apps and devices. Given these inherent risks, taking a proactive stance by blocking KernelSU becomes a crucial defensive strategy. By preventing its usage, app developers can safeguard their applications from potential exploits, unauthorized access, and data breaches. This approach not only protects end-users but also preserves the integrity and reputation of the app itself.

Prerequisites for Using KernelSU :

To use Appdome’s mobile app security build system to Block KernelSU , you’ll need:

Block KernelSU on Android apps using Appdome

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

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

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

        Figure 1: Fusion Set that will contain the KernelSU 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 KernelSU feature via Appdome Console, to add the KernelSU 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, Circle 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 KernelSU feature via Appdome Console

      To build the KernelSU 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. When you select the KernelSU you'll notice that your Fusion Set you created in step 2.1.1 now bears the icon of the protection category that contains KernelSU

        Fusion Set applied KernelSU

        Figure 4: Fusion Set that displays the newly added KernelSU protection

      3. Select the Threat-Event™ in-app mobile Threat Defense and Intelligence policy for KernelSU :
        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 Block KernelSU .

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

          When this setting is used, Appdome detects Block KernelSU 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 KernelSU Intelligence and Control in Mobile Apps.

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

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

      4. Click Build My App at the bottom of the Build Workflow (shown in Figure 3).
    Congratulations!  The KernelSU protection is now added to the mobile app

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

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

The specifications and options for Threat-Events™ for KernelSU are:

Threat-Event™ Elements Block KernelSU Method Detail
Appdome Feature Name KernelSU
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 Blocking KernelSU Threat-Event™
Threat-Event NAME Block KernelSU
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 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

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 KernelSU is detected.

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

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

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:

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

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