How to Detect Joker Trojan Attacks Using AI

Last updated February 9, 2025 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 Joker Trojan in Android apps.

What is Joker?

Joker malware is a type of Android Trojan primarily designed to steal sensitive information and subscribe users to premium services without their consent. It operates by simulating user interaction with ads and signing up for premium services, leading to financial loss for victims. Joker uses techniques like SMS interception and stealthily interacting with webpages to complete fraudulent subscriptions. This malware often hides within seemingly legitimate apps distributed on Google Play, evading detection by employing dynamic code execution and heavy obfuscation. With Joker malware constantly evolving, attackers have integrated new evasion techniques, making it harder to detect, and increasing the risk it poses to mobile apps, login credentials, and transaction data. As Joker malware evolves, AI-based agents or frameworks could be used by attackers to further enhance its evasion techniques. AI could enable the malware to autonomously adjust its behavior based on detection patterns or adapt its interactions with subscription services to avoid being flagged, making future variants harder to detect and mitigate.

How Appdome Protects Against Joker Trojan in Android Apps

Appdome’s dynamic Detect Joker Trojan plugin for Android combines advanced protections for overlay attacks, accessibility service abuse, keyloggers and screen recording malware.It detects and blocks SMS interception and unauthorized accessibility service use, prevents malicious overlays, and stops ATS malware from hijacking transactions. Protections like screen-sharing prevention safeguard user interactions and sensitive data. Combined, these protections ensure dynamic and continous protection against Joker’s diverse attack vectors without requiring developers to write or change code. Mobile developers can leverage Appdome’s Threat-Events™ to collect detailed data and implement tailored in-app responses based on detected threats.

Prerequisites for Using Appdome's Detect Joker Trojan Plugins:

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

How to Implement Detect Joker Trojan in Android Apps Using Appdome

On Appdome, follow these 3 simple steps to create self-defending Android Apps that Detect Joker Trojan 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 Joker Trojan is compatible with: Java, JS, C++, C#, Kotlin, Flutter, React Native, Unity, Xamarin, Cordova and other Android apps.
  2. Select the defense: Detect Joker Trojan.

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

        Figure 1: Fusion Set that will contain the Detect Joker Trojan feature

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

      3. When you enable Detect Bank Trojan Apps you'll notice that the Fusion Set you created in step 2.1 now bears the icon of the protection category that contains Detect Joker Trojan.

        Fusion Set applied Detect Joker Trojan

        Figure 2: Fusion Set that displays the newly added Detect Joker Trojan 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 Joker Trojan feature to your security template.

      1. Navigate to Build > Anti ATO tab > Android Trojans section in the Appdome Console.
      2. Toggle On Detect Bank Trojan Apps > Detect Joker Trojan.
        Detect Joker Trojan option

        Figure 4: Selecting Detect Joker Trojan

        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. Configure the User Experience Options for Detect Joker Trojan:
        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 Joker Trojan

        4. Detect Joker Trojan Threat Code™. Appdome uses AI/ML to generate a unique code each time Detect Joker Trojan 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 Joker Trojan protection is now added to the mobile app
  3. Certify the Detect Joker Trojan feature in Android Apps

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

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

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

The specifications and options for Threat-Events™ for Joker Trojan are:

Threat-Event™ Elements Detect Joker Trojan Method Detail
Appdome Feature Name Detect Joker Trojan
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 x
Visible in ThreatScope™ x
Developer Parameters for Detecting Joker Trojan Threat-Event™
Threat-Event NAME
Threat-Event DATA reasonData
Threat-Event CODE reasonCode
Threat-Event REF
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 Joker Trojan is detected.


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


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 Apps by using Detect Joker Trojan. 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 Joker Trojan

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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