How to Prevent Fake iOS Apps using Signature Validation

Last updated January 29, 2023 by Appdome

Learn to Prevent the running of non-authorized apps in iOS apps, in mobile CI/CD with a Data-Driven DevSecOps™ build system.

Why Should Developers Prevent the Running of non-authorized apps?

Fraudsters and other cyber-criminals often use various methods and techniques to create fake apps by copying or cloning existing popular apps and then repackaging, re-signing, and re-distributing those apps on alternative, malicious or non-approved app stores. it is fairly easy for malicious actors to publish fake, malicious or pirated apps on app stores other than Apple’s App Store.  They only need to download a target app (such as your app) on a Jailbroken mobile device, modify the app, and then repackage, re-sign, and re-distribute the fake or pirated mobile app to any app store they want.

For additional information, see Top Reasons Cyber-criminals Publish Mobile Apps on Alternative App Stores.

How does Appdome Prevent the Running of non-Authorized Apps?

Appdome App Store Validation validates that apps signed for Apple App Store cannot be distributed through any other app stores. If the original app was signed for Apple’s App Store, Appdome prevents the app from being re-signed with a different application identifier. If the app was originally published to the app store, and the application identifier is different than the originally signed app, Appdome detects the difference and prevents the app from running.

Preventing the running of non-authorized apps on iOS apps by Using Appdome

On Appdome, follow these 3 simple steps to create self-defending iOS Apps that Prevent the running of non-authorized apps 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. iOS Formats: .ipa
  2. Build the feature: App Store Signature Validation.

    1. Building App Store Signature Validation by using Appdome’s DEV-API:

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

        Figure 1: Fusion Set that will contain the App Store Signature Validation 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 App Store Signature Validation feature via Appdome Console, to add the App Store Signature Validation 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 App Store Signature Validation feature via Appdome Console

      To build the App Store Signature Validation protection by using Appdome Console, follow the instructions below.

      1. Where: Inside the Appdome Console, go to Build > Anti Fraud Tab > Mobile Cheat Prevention section
      2. How: Toggle (turn ON) App Store Signature Validation, 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 the running of non-authorized apps. App Store Signature Validation option

        Figure 3: Prevent the running of non-authorized apps 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.

      3. When you select the App Store Signature Validation you'll notice that your Fusion Set you created in step 2.1.1 now bears the icon of the protection category that contains App Store Signature Validation

        Fusion Set applied App Store Signature Validation

        Figure 4: Fusion Set that displays the newly added App Store Signature Validation protection

      4. Select the Threat-Event™ in-app mobile Threat Defense and Intelligence policy for App Store Signature Validation:
        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 Prevent the running of non-authorized apps.

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

          When this setting is used, Appdome detects an attempt to install an app from a non-official App Store. 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 App Store Signature Validation Intelligence and Control in Mobile Apps.

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

          When this setting is used, Appdome detects and defends against the running of non-authorized apps (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 App Store Signature Validation Intelligence and Control in Mobile Apps.

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

Using Threat-Events™ for the running of non-authorized apps Intelligence and Control in iOS Apps

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

The specifications and options for Threat-Events™ for the running of non-authorized apps are:

Threat-Event™ Elements Prevent the running of non-authorized apps Method Detail
Appdome Feature Name App Store Signature Validation
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 the running of non-authorized apps Threat-Event™
Threat-Event NAME This app cannot be installed from unofficial app stores. For your protection, the app will close. Please contact support
Threat-Event DATA reasonData
Threat-Event CODE reasonCode
Threat-Event REF 6902
Threat-Event SCORE
currentThreatEventScore Current Threat-Event score
threatEventsScore Total Threat-events score
Threat-Event Context Keys
blocked was the keyboard blocked (True/False)
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 iOS SDK Version
timestamp UNIX timestamp when event happened
OS Platform(s) Method iOS (registerReceiver)

With Threat-Events™ enabled (turned ON), iOS developers can get detailed attack intelligence and granular defense control in iOS applications and create amazing user experiences for all mobile end users when the running of non-authorized apps is detected.

The following is a code sample for native iOS apps, which uses all values in the specification above for App Store Signature Validation:

Prerequisites to Using App Store Signature Validation:

To use Appdome’s mobile app security build system to Prevent the running of non-authorized apps , you’ll need:

Using Appdome, there are no development or coding prerequisites to build secured Apps by using App Store Signature Validation. 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 App Store Signature Validation

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:

All apps protected by Appdome are fully compatible with any public app store, including Apple App Store, Google Play, Huawei App Gallery and more.

Features Similar to App Store Signature Validation

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.

NEED HELP?

let's solve it together

AnanyaMaking your security project a success!
By filling out this form, you opt-in to recieve emails from us.