How to Detect SIM Card Swapping in Android & iOS Apps

Last updated April 18, 2024 by Appdome

Learn to Detect SimStateInfo in Mobile apps, in mobile CI/CD with a Data-Driven DevSecOps™ build system.

What is a SIM Swap Attack?

A SIM swap attack is a form of identity theft where cybercriminals trick a cellular service provider into transferring a victim’s service to a SIM card under their control. This allows the attacker to hijack the victim’s phone number and intercept texts and calls, including crucial password recovery and account verification codes. The primary objective of SIM swapping is to exploit two-factor authentication to gain unauthorized access to sensitive accounts like banking or social media.


Why Detecting SIM Card Swapping is Vital ?

Each SIM card has a unique identifier, which mobile networks use to deliver services and communications to the correct device. In a SIM swap scenario, the victim’s cellular account gets linked to a different SIM card, diverting all incoming network traffic to the attacker. This kind of attack is a significant threat because it can bypass two-factor authentication, rendering standard security measures ineffective. Appdome’s ‘Detect SIM Swap’ feature is designed to detect the presence of a SIM swap within a mobile application and send a threat event notification to the app developer. This early detection is fundamental in enabling a prompt response to potential security breaches. This is especially important for apps that handle financial transactions or personal data, where the consequences of unauthorized access can be severe. Detecting SIM swaps in real time helps maintain the integrity of the user’s mobile experience and trust in the application’s security protocols.

Note: If you receive the following message, please ensure that your app is running on the correct Appdome engine version.

App Without Read Phone State Permission

Prerequisites for Using Detect SIM Swap:

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

Detect SimStateInfo on Mobile apps using Appdome

On Appdome, follow these 3 simple steps to create self-defending Mobile Apps that Detect SimStateInfo 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. Mobile App Formats: .ipa for iOS, or .apk or .aab for Android
    4. Detect SIM Swap Compatible With: Obj-C, C+, Java, JS, C#, C++, Swift, Kotlin, Flutter, React Native, Unity, Xamarin, and more
  2. Build the feature: Detect SIM Swap.

    1. Building Detect SIM Swap by using Appdome’s DEV-API:

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

        Figure 1: Fusion Set that will contain the Detect SIM Swap 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 Detect SIM Swap feature via Appdome Console, to add the Detect SIM Swap 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, Cirlce 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 Detect SIM Swap feature via Appdome Console

      To build the Detect SIM Swap protection by using Appdome Console, follow the instructions below.

      1. Where: Inside the Appdome Console, go to Build > Anti Fraud Tab > Social Engineering Prevention section.
      2. When you select the Detect SIM Swap 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 SIM Swap

        Fusion Set applied Detect SIM Swap

        Figure 4: Fusion Set that displays the newly added Detect SIM Swap protection

      3. Select the Threat-Event™ in-app mobile Threat Defense and Intelligence policy for Detect SIM Swap:
        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 Detect SimStateInfo.

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

          When this setting is used, Appdome detects the presence of SIM card swapping 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 SIM Swap Intelligence and Control in Mobile Apps.

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

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

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

Using Threat-Events™ for SimStateInfo Intelligence and Control in Mobile Apps

Appdome Threat-Events™ provides consumable in-app mobile app attack intelligence and defense control when SimStateInfo is detected. To consume and use Threat-Events™ for SimStateInfo in Mobile Apps, use AddObserverForName in Notification Center, and the code samples for Threat-Events™ for SimStateInfo shown below.

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

Threat-Event™ Elements Detect SimStateInfo Method Detail
Appdome Feature Name Detect SIM Swap
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 SimStateInfo Threat-Event™
Threat-Event NAME SimStateInfo
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), 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 SimStateInfo is detected.

The following is a code sample for native Mobile apps, which uses all values in the specification above for Detect SIM Swap:

Using Appdome, there are no development or coding prerequisites to build secured Mobile Apps by using Detect SIM Swap. 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 SIM Swap

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 to Prevent Social Engineering Attacks in Android & iOS Apps

How to Prevent Vishing Fraud in Android & iOS Apps

How to Block Remote Desktop Exploits in iOS Apps

How to Block Remote Desktop Exploits in Android Apps

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

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