How to Prevent Mods & Hacks that Require Re-Signing Mobile Apps

Last updated August 28, 2022 by Appdome

Learn to Prevent App Piracy in iOS apps, in mobile CI/CD with a Data-Driven DevSecOps™ build system.

What is App Piracy?

Fraudsters and other cyber-criminals routinely use jailbroken phones to copy, clone, or embed malware inside legitimate mobile apps. After that, they repackage, re-sign, and try either to send the apps that has been tampered with to another individual or to re-distribute these fake/malicious apps to an app store (Apple’s App Store or an alternative app store). These apps are sent or re-distributed for malicious uses, such as creating malware trojans and malicious versions for compromising and attacking mobile users.

How does Appdome Prevent App Piracy in iOS Apps ?

Appdome’s Secure App Signature feature validates the app signature to ensure the app has been signed by an authorized developer. When you build an iOS with Appdome’s Secure App Signature feature, Appdome saves the application identifier at the time the app is signed by the authorized developer.  If the application identifier has changed, Appdome will detect it and prevent the app from running.

Secure App Signature prevents mobile app piracy, as well as fakes, clones, mods, and tweaks by ensuring that only authorized developers can sign and distribute apps.

Preventing App Piracy on iOS apps by Using Appdome

On Appdome, follow these 3 simple steps to create self-defending iOS Apps that Prevent App Piracy 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 Protection: Secure App Signature.

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

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

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

      To build the Secure App Signature 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) Secure App Signature, as shown belowApp Piracy, If needed, Customize the Threat Notification to be displayed to the mobile end-user in a standard OS dialog notification when Appdome Prevents . Secure App Signature option

        Figure 3: Prevent App Piracy 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 Secure App Signature you'll notice that your Fusion Set you created in step 2.1.1 now bears the icon of the protection category that contains Secure App Signature

        Fusion Set applied Secure App Signature

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

      4. Select the Threat-Event™ in-app mobile Threat Defense and Intelligence policy for Secure App Signature:
        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 App Piracy.

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

          When this setting is used, Appdome detects if an iOS app has been resigned by non-authorized developer 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 Secure App Signature Intelligence and Control in Mobile Apps.

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

          When this setting is used, Appdome detects and defends against App Piracy (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 Secure App Signature Intelligence and Control in Mobile Apps.

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

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

    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 Secure App Signature has been added to each iOS app. Certified Secure provides instant and in-line DevSecOps compliance certification that Secure App Signature and other mobile app security features are in each build of the mobile app

Using Threat-Events™ for App Piracy Intelligence and Control in iOS Apps

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

The specifications and options for Threat-Events™ for App Piracy are:

Threat-Event™ Elements Prevent App Piracy Method Detail
Appdome Feature Name Secure App Signature
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 App Piracy Threat-Event™
Threat-Event NAME SecureSignatureAppResigned
Threat-Event DATA reasonData
Threat-Event CODE reasonCode
Threat-Event REF 6903
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 App Piracy is detected.

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

Prerequisites to Using Secure App Signature:

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

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

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.

Protections Similar to Secure App Signature

Here are a few related resources:

How to Prevent non-approved Android, iOS app store publishing

Runtime bundle validation

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.

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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