How to Prevent Vishing Fraud in Android & iOS Apps
Learn to Prevent Vishing Fraud in Mobile apps, in mobile CI/CD with a Data-Driven DevSecOps™ build system.
What is Vishing Fraud?
Preventing Vishing fraud focuses on identifying instances where a mobile app is used during an active phone call. While this concurrent use isn’t inherently fraudulent, it becomes significant in certain contexts, particularly during sensitive transactions. For example, if an individual engages in a mobile app activity while on an active call related to a sensitive transaction (such as discussing financial details, making a high-value purchase, or conducting a verification process), this parallel action could raise a security alert. The feature doesn’t automatically assume fraud per se but rather flags such scenarios for additional scrutiny. This is due to the potential risks associated with the simultaneous handling of sensitive activities, which might be indicative of suspicious behavior.
Why Detecting Vishing Fraud is Vital?
While using a mobile app during an active call is not inherently fraudulent, the context and the specific actions being performed simultaneously can raise alerts within fraud detection systems. This is done to protect users and organizations from potential fraudulent activities, identity theft, or security breaches. These alerts trigger further verification steps or investigation to ensure the legitimacy and security of transactions or interactions taking place. This becomes particularly critical when we examine real-world scenarios where such detection capabilities are essential such as:
Fraud Patterns: In some cases, fraudsters may use multiple channels simultaneously to perpetrate fraudulent activities. For example, they might attempt to social engineer a call center representative while using an app to manipulate or access accounts simultaneously. Such simultaneous activities could raise red flags in fraud detection systems.
Anomalous Behavior: Unusual behavior patterns detected by fraud detection systems, such as a sudden change in user behavior (like accessing a banking app during an ongoing call with a customer service representative for an account-related issue), might trigger alerts for potential fraudulent activities.
Risk Mitigation: For security reasons, certain organizations or financial institutions might set policies or algorithms that flag any deviation from standard user behavior, especially during sensitive transactions, to mitigate potential risks associated with fraud or data breaches.
How does Appdome Protect Mobile Apps Against Vishing Fraud?
To protect Android & iOS apps against Vishing Fraud, Appdome implements the following detection methods:
1. App In Use: Detects vishing attempts when the app is actively being used, during incoming calls.
2. App In Foreground: Scans for vishing attempts when the app is open and visible on the screen.
3. User Uses App and Call Together: Detects simultaneous app use and phone calls.
4. User Opens App after Call Starts: Detects if the app is launched after a phone call has begun, for vishing risk assessment.
All these protection measures are designed to provide an extra layer of security, alerting app developers to suspicious calls that could be attempting to steal app users personal details or financial information.”
Prerequisites for Using Vishing Fraud Prevention:
To use Appdome’s mobile app security build system to Prevent Vishing Fraud , you’ll need:
- Appdome account (create a free Appdome account here)
- A license for Vishing Fraud Prevention
- Mobile App (.ipa for iOS, or .apk or .aab for Android)
- Signing Credentials (see Signing Secure Android apps and Signing Secure iOS apps)
Prevent Vishing Fraud on Mobile apps using Appdome
On Appdome, follow these 3 simple steps to create self-defending Mobile Apps that Prevent Vishing Fraud without an SDK or gateway:
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Upload the Mobile App to Appdome.
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Upload an app to Appdome’s Mobile App Security Build System
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Upload Method: Appdome Console or DEV-API
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Mobile App Formats: .ipa for iOS, or .apk or .aab for Android
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Vishing Fraud Prevention Compatible With: Obj-C, Java, JS, C#, C++, Swift, Kotlin, Flutter, React Native, Unity, Xamarin, and more
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Build the feature: Vishing Fraud Prevention.
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Building Vishing Fraud Prevention by using Appdome’s DEV-API:
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Create and name the Fusion Set (security template) that will contain the Vishing Fraud Prevention feature as shown below:
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Follow the steps in Sections 2.2.1-2.2.2 of this article, Building the Vishing Fraud Prevention feature via Appdome Console, to add the Vishing Fraud Prevention feature to this Fusion Set.
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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):
Figure 2: Fusion Set Detail Summary
Note: Annotating the Fusion Set to identify the protection(s) selected is optional only (not mandatory). -
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:
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Build an API for the app – for instructions, see the tasks under Appdome API Reference Guide
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Look for sample APIs in Appdome’s GitHub Repository
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Figure 1: Fusion Set that will contain the Vishing Fraud Prevention feature
Note: Naming the Fusion Set to correspond to the protection(s) selected is for illustration purposes only (not required). -
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Building the Vishing Fraud Prevention feature via Appdome Console
To build the Vishing Fraud Prevention protection by using Appdome Console, follow the instructions below.
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Where: Inside the Appdome Console, go to Build > Anti Fraud Tab > Social Engineering Prevention section.
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How: Check whether is toggled On (enabled), otherwise enable it . The feature Vishing Fraud Prevention is enabled by default, as shown below. Toggle (turn ON) Vishing Fraud Prevention, 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 Prevents Vishing Fraud.
Figure 3: Prevent Vishing Fraud 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. -
When you select the Vishing Fraud Prevention you'll notice that your Fusion Set you created in step 2.1.1 now bears the icon of the protection category that contains Vishing Fraud Prevention
Figure 4: Fusion Set that displays the newly added Vishing Fraud Prevention protection
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Select the Threat-Event™ in-app mobile Threat Defense and Intelligence policy for Vishing Fraud Prevention:
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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 Vishing Fraud.
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Threat-Events™ ON > In-App Detection
When this setting is used, Appdome detects if a call is taking place while an application is open on the mobile device 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 Vishing Fraud Prevention Intelligence and Control in Mobile Apps.
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Threat-Events™ ON > In-App Defense
When this setting is used, Appdome detects and defends against Vishing Fraud (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 Vishing Fraud Prevention Intelligence and Control in Mobile Apps.
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Click Build My App at the bottom of the Build Workflow (shown in Figure 3).
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Congratulations! The Vishing Fraud Prevention protection is now added to the mobile app -
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Certify the Vishing Fraud Prevention feature in Mobile Apps
After building Vishing Fraud Prevention, Appdome generates a Certified Secure™ certificate to guarantee that the Vishing Fraud Prevention protection has been added and is protecting the app. To verify that the Vishing Fraud Prevention 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 Vishing Fraud Prevention has been added to each Mobile app. Certified Secure provides instant and in-line DevSecOps compliance certification that Vishing Fraud Prevention and other mobile app security features are in each build of the mobile app
Using Threat-Events™ for Vishing Fraud Intelligence and Control in Mobile Apps
Appdome Threat-Events™ provides consumable in-app mobile app attack intelligence and defense control when Vishing Fraud is detected. To consume and use Threat-Events™ for Vishing Fraud in Mobile Apps, use AddObserverForName in Notification Center, and the code samples for Threat-Events™ for Vishing Fraud shown below.
The specifications and options for Threat-Events™ for Vishing Fraud are:
| Threat-Event™ Elements | Prevent Vishing Fraud Method Detail |
|---|---|
| Appdome Feature Name | Vishing Fraud Prevention |
| 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 Preventing Vishing Fraud Threat-Event™ | |
| Threat-Event NAME | ActivePhoneCallDetected |
| 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 |
| 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 |
With Threat-Events™ enabled (turned ON), Mobile developers can get detailed attack intelligence and granular defense control in Mobile applications and create amazing user experiences for all mobile end users when Vishing Fraud is detected.
The following is a code sample for native Mobile apps, which uses all values in the specification above for Vishing Fraud Prevention:
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.
xxxxxxxxxxIntentFilter intentFilter = new IntentFilter();intentFilter.addAction("ActivePhoneCallDetected");BroadcastReceiver threatEventReceiver = new BroadcastReceiver() { 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 // Current threat event score String currentThreatEventScore = intent.getStringExtra("currentThreatEventScore"); // Total threat events score String threatEventsScore = intent.getStringExtra("threatEventsScore"); // Replace '<Context Key>' with your specific event context key // String variable = intent.getStringExtra("<Context Key>"); // Your logic goes here (Send data to Splunk/Dynatrace/Show Popup...) }};if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.TIRAMISU) { registerReceiver(threatEventReceiver, intentFilter, Context.RECEIVER_NOT_EXPORTED);} else { registerReceiver(threatEventReceiver, intentFilter);}xxxxxxxxxxval intentFilter = IntentFilter()intentFilter.addAction("ActivePhoneCallDetected")val threatEventReceiver = 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 // Current threat event score var currentThreatEventScore = intent?.getStringExtra("currentThreatEventScore") // Total threat events score var threatEventsScore = intent?.getStringExtra("threatEventsScore") // Replace '<Context Key>' with your specific event context key // var variable = intent?.getStringExtra("<Context Key>") // Your logic goes here (Send data to Splunk/Dynatrace/Show Popup...) }}if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.TIRAMISU) { registerReceiver(threatEventReceiver, intentFilter, Context.RECEIVER_NOT_EXPORTED)} else { registerReceiver(threatEventReceiver, intentFilter)}x
let center = NotificationCenter.defaultcenter.addObserver(forName: Notification.Name("ActivePhoneCallDetected"), object: nil, queue: nil) { (note) in guard let usrInf = note.userInfo else { return } let message = usrInf["message"]; // Message shown to the user let reasonData = usrInf["reasonData"]; // Threat detection cause let reasonCode = usrInf["reasonCode"]; // Event reason code // Current threat event score let currentThreatEventScore = usrInf["currentThreatEventScore"]; // Total threat events score let threatEventsScore = usrInf["threatEventsScore"]; // Replace '<Context Key>' with your specific event context key // let variable = usrInf["<Context Key>"]; // Your logic goes here (Send data to Splunk/Dynatrace/Show Popup...)}xxxxxxxxxx[[NSNotificationCenter defaultCenter] addObserverForName: @"ActivePhoneCallDetected" object:nil queue:nil usingBlock:^(NSNotification *org_note) { __block NSNotification *note = org_note; dispatch_async(dispatch_get_main_queue(), ^(void) { // Message shown to the user NSString *message = [[note userInfo] objectForKey:@"message"]; // Threat detection cause NSString *reasonData = [[note userInfo] objectForKey:@"reasonData"]; // Event reason code NSString *reasonCode = [[note userInfo] objectForKey:@"reasonCode"]; // Current threat event score NSString *currentThreatEventScore = [[note userInfo] objectForKey:@"currentThreatEventScore"]; // Total threat events score NSString *threatEventsScore = [[note userInfo] objectForKey:@"threatEventsScore"]; // Replace '<Context Key>' with your specific event context key // NSString *variable = [[note userInfo] objectForKey:@"<Context Key>"]; // Your logic goes here (Send data to Splunk/Dynatrace/Show Popup...) });}];xxxxxxxxxxconst { ADDevEvents } = NativeModules;const aDDevEvents = new NativeEventEmitter(ADDevEvents);function registerToDevEvent(action, callback) { NativeModules.ADDevEvents.registerForDevEvent(action); aDDevEvents.addListener(action, callback);}export function registerToAllEvents() { registerToDevEvent( "ActivePhoneCallDetected", (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 // Current threat event score var currentThreatEventScore = userinfo["currentThreatEventScore"] // Total threat events score var threatEventsScore = userinfo["threatEventsScore"] // Replace '<Context Key>' with your specific event context key // var variable = userinfo["<Context Key>"] // Your logic goes here (Send data to Splunk/Dynatrace/Show Popup...) );}x
RegisterReceiver(new ThreatEventReceiver(), new IntentFilter("ActivePhoneCallDetected")); class ThreatEventReceiver : BroadcastReceiver{ public override void OnReceive(Context context, Intent intent) { // Message shown to the user String message = intent.GetStringExtra("message"); // Threat detection cause String reasonData = intent.GetStringExtra("reasonData"); // Event reason code String reasonCode = intent.GetStringExtra("reasonCode"); // Current threat event score String currentThreatEventScore = intent.GetStringExtra("currentThreatEventScore"); // Total threat events score String threatEventsScore = intent.GetStringExtra("threatEventsScore"); // Replace '<Context Key>' with your specific event context key // String variable = intent.GetStringExtra("<Context Key>"); // Your logic goes here (Send data to Splunk/Dynatrace/Show Popup...) }}x
NSNotificationCenter.DefaultCenter.AddObserver( (NSString)"ActivePhoneCallDetected", // Threat-Event Identifier delegate (NSNotification notification) { // Message shown to the user var message = notification.UserInfo.ObjectForKey("message"); // Threat detection cause var reasonData = notification.UserInfo.ObjectForKey("reasonData"); // Event reason code var reasonCode = notification.UserInfo.ObjectForKey("reasonCode"); // Current threat event score var currentThreatEventScore = notification.UserInfo.ObjectForKey("currentThreatEventScore"); // Total threat events score var threatEventsScore = notification.UserInfo.ObjectForKey("threatEventsScore"); // Replace '<Context Key>' with your specific event context key // var variable = notification.UserInfo.ObjectForKey("<Context Keys>"); // Your logic goes here (Send data to Splunk/Dynatrace/Show Popup...) });xxxxxxxxxxwindow.broadcaster.addEventListener("ActivePhoneCallDetected", 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 // Current threat event score var currentThreatEventScore = userInfo.currentThreatEventScore // Total threat events score var threatEventsScore = userInfo.threatEventsScore // Replace '<Context Key>' with your specific event context key // var variable = userInfo.<Context Keys> // Your logic goes here (Send data to Splunk/Dynatrace/Show Popup...)});x
import 'dart:async';import 'package:flutter/material.dart';import 'package:flutter/services.dart';class PlatformChannel extends StatefulWidget { const PlatformChannel({super.key}); State<PlatformChannel> createState() => _PlatformChannelState();}class _PlatformChannelState extends State<PlatformChannel> { // Replace with your EventChannel name static const String _eventChannelName = "ActivePhoneCallDetected"; static const EventChannel _eventChannel = EventChannel(_eventChannelName); void initState() { super.initState(); _eventChannel.receiveBroadcastStream().listen(_onEvent, onError: _onError); } void _onEvent(Object? event) { setState(() { // Adapt this section based on your specific event data structure var eventData = event as Map; // Example: Accessing 'externalID' field from the event var externalID = eventData['externalID']; // Customize the rest of the fields based on your event structure String message = eventData['message']; // Message shown to the user String reasonData = eventData['reasonData']; // Threat detection cause String reasonCode = eventData['reasonCode']; // Event reason code // Current threat event score String currentThreatEventScore = eventData['currentThreatEventScore']; // Total threat events score String threatEventsScore = eventData['threatEventsScore']; // Replace '<Context Key>' with your specific event context key // String variable = eventData['<Context Keys>']; }); } // Your logic goes here (Send data to Splunk/Dynatrace/Show Popup...)}Using Appdome, there are no development or coding prerequisites to build secured Mobile Apps by using Vishing Fraud Prevention. 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 Vishing Fraud Prevention
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.
Related Articles:
- How to Block Team Viewer & Remote Desktop Exploits in iOS Apps
- How to Detect SIM Card Swapping in Android & iOS Apps
- How to Block Remote Desktop Exploits in Android Apps
- How to Detect Fake Location in Android Apps
- How to Implement VPN Detection for Android & iOS Apps
- How to Detect Fake GPS Location Inside Android & iOS Apps
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.
