How to Protect iOS Apps from FlyJB Jailbreak Detection Bypass

Last updated August 11, 2022 by Appdome

Learn to Block FlyJB Jailbreak Detection Bypass in iOS apps, in mobile CI/CD with a Data-Driven DevSecOps™ build system.

What is FlyJB?

FlyJB is a jailbreak detection bypass tool that allows users to bypass in-app jailbreak detection mechanisms. It also claims to allow bypassing the built-in DRM (Digital Rights Management) of App Store applications to prevent them from checking whether or not your device is jailbroken. Finally, it claims to disable Substitute or Cydia Substrate, thereby preventing tweaks from hooking into an app.

Jailbreaking is the process of unlocking the iOS operating system on an Apple mobile device. A successful jailbreaking operation is a form of administrative privilege escalation, which bypasses Apple’s restrictions, resulting in full administrative control over the OS (the highest level of administrative privilege possible). Hackers often manage to perform jailbreaking by exploiting bugs in Apple’s software/firmware or modifying system kernels to allow read and write access to the file system.

Why Block FlyJB ?

Hackers use Jailbreak Bypass tools like FlyJB to evade Jailbreak detection/protections. Jailbreaking makes it easier to hack iOS apps and to compromise the mobile security model. So if a mobile app is protected with Jailbreak detection or Jailbreak protection, hackers will try to either bypass the protection or hide the fact that the device is Jailbroken and can continue to do whatever activity they used Jailbreak to achieve over a longer period of time and without being noticed.

To avoid detection, hackers combine Jailbreak tools with Jailbreak detection bypass tools to kill two birds with one stone. For example, hackers combine the use of Jailbreak tools such as CheckRa1n,Unc0ver, Zylon, PlankFilza, and Chimera, with Jailbreak Bypass or Jailbreak hiding tools like FlyJB.

Blocking FlyJB in iOS apps is automatically enabled when Block Jailbreak Detection Bypass is enabled in the Fusion Set.

Blocking FlyJB Jailbreak Detection Bypass on iOS apps by Using Appdome

On Appdome, follow these 3 simple steps to create self-defending iOS Apps that Block FlyJB Jailbreak Detection Bypass 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: Block Jailbreak Bypass Tools.

    1. Building Block Jailbreak Bypass Tools by using Appdome’s DEV-API:

      1. Create and name the Fusion Set (security template) that will contain the Block Jailbreak Bypass Tools feature as shown below:
      2. fusion set that contains Block Jailbreak Bypass Tools

        Figure 1: Fusion Set that will contain the Block Jailbreak Bypass Tools 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 Block Jailbreak Bypass Tools feature via Appdome Console, to add the Block Jailbreak Bypass Tools 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 Block Jailbreak Bypass Tools feature via Appdome Console

      To build the Block Jailbreak Bypass Tools protection by using Appdome Console, follow the instructions below.

      1. Where: Inside the Appdome Console, go to Build > Anti Fraud Tab > Mobile Malware Prevention section
      2. How: Toggle (turn ON) Block Jailbreak Bypass Tools, as shown below. Block Jailbreak Bypass Tools option

        Figure 3: Block FlyJB Jailbreak Detection Bypass option

      3. When you select the Block Jailbreak Bypass Tools you'll notice that your Fusion Set you created in step 2.1.1 now bears the icon of the protection category that contains Block Jailbreak Bypass Tools

        Fusion Set applied Block Jailbreak Bypass Tools

        Figure 4: Fusion Set that displays the newly added Block Jailbreak Bypass Tools protection

      4. Select the Threat-Event™ in-app mobile Threat Defense and Intelligence policy for Block Jailbreak Bypass Tools:
        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 Block FlyJB Jailbreak Detection Bypass .

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

          When this setting is used, Appdome detects the use of FlyJB 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 Block Jailbreak Bypass Tools Intelligence and Control in Mobile Apps.

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

          When this setting is used, Appdome detects and defends against FlyJB Jailbreak Detection Bypass (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 Block Jailbreak Bypass Tools Intelligence and Control in Mobile Apps.

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

    After building Block Jailbreak Bypass Tools, Appdome generates a Certified Secure™ certificate to guarantee that the Block Jailbreak Bypass Tools protection has been added and is protecting the app. To verify that the Block Jailbreak Bypass Tools protection has been added to the mobile app, locate the protection in the Certified Secure™ certificate as shown below: Block Jailbreak Bypass Tools 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 Block Jailbreak Bypass Tools has been added to each iOS app. Certified Secure provides instant and in-line DevSecOps compliance certification that Block Jailbreak Bypass Tools and other mobile app security features are in each build of the mobile app

Using Threat-Events™ for FlyJB Jailbreak Detection Bypass Intelligence and Control in iOS Apps

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

The specifications and options for Threat-Events™ for FlyJB Jailbreak Detection Bypass are:

Threat-Event™ Elements Block FlyJB Jailbreak Detection Bypass Method Detail
Appdome Feature Name Block Jailbreak Bypass Tools
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 Blocking FlyJB Jailbreak Detection Bypass Threat-Event™
Threat-Event NAME JailbreakBypassDetected
Threat-Event DATA reasonData
Threat-Event CODE reasonCode
Threat-Event REF 6924
Threat-Event SCORE
currentThreatEventScore Current Threat-Event score
threatEventsScore Total Threat-events score
Threat-Event Context Keys
messageMessage displayed for the user on event
externalIDThe external ID of the event which can be listened via Threat Events
osVersionOS version of the current device
deviceModelCurrent device model
deviceManufacturerThe manufacturer of the current device
fusedAppTokenThe task ID of the Appdome fusion of the currently running app
kernelInfoInfo about the kernel: system name, node name, release, version and machine.
carrierPlmnPLMN of the device
deviceIDCurrent device ID
reasonCodeReason code of the occured event
buildDateAppdome fusion date of the current application
devicePlatformOS name of the current device
carrierNameCarrier name of the current device
updatedOSVersionIs the OS version up to date
timeZoneTime zone
deviceFaceDownIs the device face down
locationLongLocation long
locationLatLocation lat
locationStateLocation state
wifiSsidWifi SSID
wifiSsidPermissionStatusWifi SSID permission status
reasonDetection cause
dataDetection cause data

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 FlyJB Jailbreak Detection Bypass is detected.

The following is a code sample for native iOS apps, which uses all values in the specification above for Block Jailbreak Bypass Tools:

Prerequisites to Using Block Jailbreak Bypass Tools:

To use Appdome’s mobile app security build system to Block FlyJB Jailbreak Detection Bypass , you’ll need:

Using Appdome, there are no development or coding prerequisites to build secured Apps by using Block Jailbreak Bypass Tools. 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 Block Jailbreak Bypass Tools

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 Block Jailbreak Bypass Tools

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

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