How to Detect Malware Privilege Escalation to AccessibilityService

Last updated August 11, 2022 by Appdome

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

What is Android AccessibilityService?

AccessibilityServices are OS settings/features in Android that are designed to help users with disabilities (for example: screen readers, speech to text, touch events). These features run in the background and receive callbacks by the system when accessibility events are fired, making them capable of reacting to a state transition in the UI (for example: focus has changed, button was clicked, or content in the active window was queried).

Why Prevent AccessibilityService abuse in Android Apps ?

AccessibilityServices features enabled in an app typically provide the app with permissions that can be abused, especially if the app is a clone, trojan, or malware app. Such malicious apps often request elevated permissions or trick users into enabling AccessibilityServices which the app will then abuse (at the expense of the user or your app). The malware might abuse the user or target application by using the Accessibility feature or associated permissions for malicious and unintended reasons. The potential malicious uses of AccessibilityServices services include performing click actions (for example, committing click fraud, inputting data into forms fraudulently, impersonating the real mobile user, or cheating in mobile games). Other potential abusive actions are reading and writing SMS messages and emails, intercepting and reading 2FA codes, stealing cryptocurrency keys, and remotely controlling mobile devices or apps.
For these reasons, it is advisable to be aware that the AccessibilityServices services are enabled for a malicious app and protect the target application (your app) from being abused or compromised.

Preventing AccessibilityService abuse on Android apps by Using Appdome

On Appdome, follow these 3 simple steps to create self-defending Android Apps that Prevent AccessibilityService abuse without an SDK or gateway:

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
Build the Protection: Detect Accessibility Abuse.
1. Building Detect Accessibility Abuse by using Appdome’s DEV-API:
  1. Create and name the Fusion Set (security template) that will contain the Detect Accessibility Abuse feature as shown below:
  2. Follow the steps in Sections 2.2.1-2.2.2 of this article, Building the Detect Accessibility Abuse feature via Appdome Console, to add the Detect Accessibility Abuse feature to this Fusion Set.
  3. 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):
    
    Figure 2: Fusion Set Detail Summary
    Note: Annotating the Fusion Set to identify the protection(s) selected is optional only (not mandatory).
  4. 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:
    
    Build an API for the app – for instructions, see the tasks under Appdome API Reference Guide
    
    Look for sample APIs in Appdome’s GitHub Repository
2. Building the Detect Accessibility Abuse feature via Appdome Console
  
  To build the Detect Accessibility Abuse protection by using Appdome Console, follow the instructions below.
  1. Where: Inside the Appdome Console, go to Build > Anti Fraud Tab > Mobile Fraud Prevention section
  2. How: Toggle (turn ON) Detect Accessibility Abuse, as shown below.
    
    Figure 3: Prevent AccessibilityService abuse option
  3. When you select the Detect Accessibility Abuse 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 Accessibility Abuse
    
    Figure 4: Fusion Set that displays the newly added Detect Accessibility Abuse protection
  4. Select the Threat-Event™ in-app mobile Threat Defense and Intelligence policy for Detect Accessibility Abuse:
    
    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 Prevent AccessibilityService abuse.
    
    Threat-Events™ ON > In-App Detection
    When this setting is used, Appdome detects that the AccessibilityServices services are enabled 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 Accessibility Abuse Intelligence and Control in Mobile Apps.
    
    Threat-Events™ ON > In-App Defense
    When this setting is used, Appdome detects and defends against AccessibilityService abuse (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 Accessibility Abuse Intelligence and Control in Mobile Apps.
  5. Optional Configuration with Detect Accessibility Abuse:
    Allow Accessibility with Specified Apps
    Allows adding one or more apps that have been approved to enable and use Android AccessibilityService.
  6. Click Build My App at the bottom of the Build Workflow (shown in Figure 3).
Congratulations! The Detect Accessibility Abuse protection is now added to the mobile app
Certify the Detect Accessibility Abuse feature in Android Apps.

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

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

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

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

The specifications and options for Threat-Events™ for AccessibilityService abuse are:

Threat-Event™ Elements	Prevent AccessibilityService abuse Method Detail
Appdome Feature Name	Detect Accessibility Abuse
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 Preventing AccessibilityService abuse Threat-Event™
Threat-Event NAME	AccessibilityServiceDetected
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
blocked	was the keyboard blocked (True/False)
buildHost	build server of the ROM (for Android devices)
deviceBoard	the board upon which the mobile device is based (for Android devices)
carrierPlmn	carrier identity number (PLMN code)
defaultMessage	the message that would be shown to the user in enforcement mode
deviceBrand	brand of the mobile device
deviceID	unique mobile installation identifier
deviceManufacturer	manufacturer of the mobile device
deviceModel	mobile device model
extendedMessageText	allows receiving extended metadata about threat events. Available only if the option
fusedAppToken	Appdome Built ID App Token
kernelInfo	Kernel information and details
Keyboard	package ID of the unauthorized keyboard to which the user tried to switch
osVersion	The mobile device OS version
sdkversion	Android SDK Version
timestamp	UNIX timestamp when event happened
OS Platform(s) Method	Android (registerReceiver)

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 AccessibilityService abuse is detected.

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

IntentFilter intentFilter = new IntentFilter();
                    intentFilter.addAction("AccessibilityServiceDetected");
                    registerReceiver(new BroadcastReceiver() {
                            @Override
                            public void onReceive(Context context, Intent intent) {
                                String message = intent.getStringExtra("message"); // Message shown to the user
                                String reasonData = intent.getStringExtra("reasonData"); // Threat detection cause
                                String reasonCode = intent.getStringExtra("reasonCode"); // Event reason code
                                String currentThreatEventScore = intent.getStringExtra("currentThreatEventScore"); // Current threat event score
                                String threatEventsScore = intent.getStringExtra("threatEventsScore"); // Total threat events score
                                String variable = intent.getStringExtra("<Context Key>"); // Any other event specific context key

                                // Your logic goes here (Send data to Splunk/Dynatrace/Show Popup...)
                            }
                        }, intentFilter);

                        
                        Java
                    
​x
 
IntentFilter intentFilter = new IntentFilter();
intentFilter.addAction("AccessibilityServiceDetected");
registerReceiver(new BroadcastReceiver() {
        @Override
        public void onReceive(Context context, Intent intent) {
            String message = intent.getStringExtra("message"); // Message shown to the user
            String reasonData = intent.getStringExtra("reasonData"); // Threat detection cause
            String reasonCode = intent.getStringExtra("reasonCode"); // Event reason code
            String currentThreatEventScore = intent.getStringExtra("currentThreatEventScore"); // Current threat event score
            String threatEventsScore = intent.getStringExtra("threatEventsScore"); // Total threat events score
            String variable = intent.getStringExtra("<Context Key>"); // Any other event specific context key
​
            // Your logic goes here (Send data to Splunk/Dynatrace/Show Popup...)
        }
    }, intentFilter);

val intentFilter = IntentFilter()
                intentFilter.addAction("AccessibilityServiceDetected")
                registerReceiver(object : BroadcastReceiver() {
                    override fun onReceive(context: Context?, intent: Intent?) {
                        var message = intent.getStringExtra("message") // Message shown to the user
                        var reasonData = intent.getStringExtra("reasonData") // Threat detection cause
                        var reasonCode = intent.getStringExtra("reasonCode") // Event reason code
                        var currentThreatEventScore = intent.getStringExtra("currentThreatEventScore") // Current threat event score
                        var threatEventsScore = intent.getStringExtra("threatEventsScore") // Total threat events score
                        var variable = intent.getStringExtra("<Context Key>") // Any other event specific context key

                        // Your logic goes here (Send data to Splunk/Dynatrace/Show Popup...)
                    }
                }, intentFilter)

                         
                        Kotlin
                    
​x
 
val intentFilter = IntentFilter()
intentFilter.addAction("AccessibilityServiceDetected")
registerReceiver(object : BroadcastReceiver() {
    override fun onReceive(context: Context?, intent: Intent?) {
        var message = intent.getStringExtra("message") // Message shown to the user
        var reasonData = intent.getStringExtra("reasonData") // Threat detection cause
        var reasonCode = intent.getStringExtra("reasonCode") // Event reason code
        var currentThreatEventScore = intent.getStringExtra("currentThreatEventScore") // Current threat event score
        var threatEventsScore = intent.getStringExtra("threatEventsScore") // Total threat events score
        var variable = intent.getStringExtra("<Context Key>") // Any other event specific context key
​
        // Your logic goes here (Send data to Splunk/Dynatrace/Show Popup...)
    }
}, intentFilter)

const { ADDevEvents } = NativeModules;
                const aDDevEvents = new NativeEventEmitter(ADDevEvents);

                function registerToDevEvent(action, callback) {
                    NativeModules.ADDevEvents.registerForDevEvent(action);
                    aDDevEvents.addListener(action, callback);
                }

                export function registerToAllEvents() {
                    registerToDevEvent(
                        "AccessibilityServiceDetected",
                        (userinfo) => Alert.alert(JSON.stringify(userinfo))

                        var message = userinfo["message"] // Message shown to the user
                        var reasonData = userinfo["reasonData"] // Threat detection cause
                        var reasonCode = userinfo["reasonCode"] // Event reason code
                        var currentThreatEventScore = userinfo["currentThreatEventScore"] // Current threat event score
                        var threatEventsScore = userinfo["threatEventsScore"] // Total threat events score
                        var variable = userinfo["<Context Key>"] // Any other event specific context key

                        // Your logic goes here (Send data to Splunk/Dynatrace/Show Popup...)
                    );
                }

                     
                    React Native
                
​x
 
const { ADDevEvents } = NativeModules;
const aDDevEvents = new NativeEventEmitter(ADDevEvents);
​
function registerToDevEvent(action, callback) {
    NativeModules.ADDevEvents.registerForDevEvent(action);
    aDDevEvents.addListener(action, callback);
}
​
export function registerToAllEvents() {
    registerToDevEvent(
        "AccessibilityServiceDetected",
        (userinfo) => Alert.alert(JSON.stringify(userinfo))
​
        var message = userinfo["message"] // Message shown to the user
        var reasonData = userinfo["reasonData"] // Threat detection cause
        var reasonCode = userinfo["reasonCode"] // Event reason code
        var currentThreatEventScore = userinfo["currentThreatEventScore"] // Current threat event score
        var threatEventsScore = userinfo["threatEventsScore"] // Total threat events score
        var variable = userinfo["<Context Key>"] // Any other event specific context key
​
        // Your logic goes here (Send data to Splunk/Dynatrace/Show Popup...)
    );
}
​

RegisterReceiver(new ThreatEventReceiver(), new IntentFilter("AccessibilityServiceDetected"));
                class ThreatEventReceiver : BroadcastReceiver
                {
                public override void OnReceive(Context context, Intent intent)
                {
                    String message = intent.getStringExtra("message"); // Message shown to the user
                    String reasonData = intent.getStringExtra("reasonData"); // Threat detection cause
                    String reasonCode = intent.getStringExtra("reasonCode"); // Event reason code
                    String currentThreatEventScore = intent.getStringExtra("currentThreatEventScore"); // Current threat event score
                    String threatEventsScore = intent.getStringExtra("threatEventsScore"); // Total threat events score
                    String variable = intent.getStringExtra("<Context Key>"); // Any other event specific context key

                    // Your logic goes here (Send data to Splunk/Dynatrace/Show Popup...)
                }
                }

                    
                    Xamarin
                
​x
 
RegisterReceiver(new ThreatEventReceiver(), new IntentFilter("AccessibilityServiceDetected"));
​
class ThreatEventReceiver : BroadcastReceiver
{
  public override void OnReceive(Context context, Intent intent)
  {
    String message = intent.getStringExtra("message"); // Message shown to the user
    String reasonData = intent.getStringExtra("reasonData"); // Threat detection cause
    String reasonCode = intent.getStringExtra("reasonCode"); // Event reason code
    String currentThreatEventScore = intent.getStringExtra("currentThreatEventScore"); // Current threat event score
    String threatEventsScore = intent.getStringExtra("threatEventsScore"); // Total threat events score
    String variable = intent.getStringExtra("<Context Key>"); // Any other event specific context key
​
    // Your logic goes here (Send data to Splunk/Dynatrace/Show Popup...)
  }
}

window.broadcaster.addEventListener("AccessibilityServiceDetected", function(userInfo) {
        var message = userInfo.message // Message shown to the user
        var reasonData = userInfo.reasonData // Threat detection cause
        var reasonCode = userInfo.reasonCode // Event reason code
        var currentThreatEventScore = userInfo.currentThreatEventScore // Current threat event score
        var threatEventsScore = userInfo.threatEventsScore // Total threat events score
        var variable = userInfo.<Context Key> // Any other event specific context key

        // Your logic goes here (Send data to Splunk/Dynatrace/Show Popup...)
            });

                    
                    Cordova
                
​x
 
window.broadcaster.addEventListener("AccessibilityServiceDetected", function(userInfo) {
        var message = userInfo.message // Message shown to the user
        var reasonData = userInfo.reasonData // Threat detection cause
        var reasonCode = userInfo.reasonCode // Event reason code
        var currentThreatEventScore = userInfo.currentThreatEventScore // Current threat event score
        var threatEventsScore = userInfo.threatEventsScore // Total threat events score
        var variable = userInfo.<Context Key> // Any other event specific context key
​
        // Your logic goes here (Send data to Splunk/Dynatrace/Show Popup...)
});

Prerequisites to Using Detect Accessibility Abuse:

To use Appdome’s mobile app security build system to Prevent AccessibilityService abuse , you’ll need:

Appdome account (create a free Appdome account here)
A license for Detect Accessibility Abuse
Mobile App (.apk or .aab For Android)
Signing Credentials (see Signing Secure iOS and Android apps)

Using Appdome, there are no development or coding prerequisites to build secured Apps by using Detect Accessibility Abuse. 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 Accessibility Abuse

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:

Customizing, Configuring & Branding Secure Mobile Apps
Deploying/Publishing Secure mobile apps to Public or Private app stores
Releasing Secured Android & iOS Apps built on Appdome.

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 Detect Accessibility Abuse

Here are a few related resources:

How to Prevent abuse of Android AccessibilityService for compromising Android apps
How to Prevent non-approved Android, iOS app store publishing
Check out the Appdome Mobile Fraud Preventionsolution page or request a demo at any time.

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.

How to Detect Malware Privilege Escalation to AccessibilityService

What is Android AccessibilityService?

Why Prevent AccessibilityService abuse in Android Apps ?

Preventing AccessibilityService abuse on Android apps by Using Appdome

Upload the Mobile App to Appdome.

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

Build the Protection: Detect Accessibility Abuse.

Building Detect Accessibility Abuse by using Appdome’s DEV-API:

Building the Detect Accessibility Abuse feature via Appdome Console

Certify the Detect Accessibility Abuse feature in Android Apps.

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

Prerequisites to Using Detect Accessibility Abuse:

Thank you!