How to Protect iOS Apps Against FlyJB Jailbreak Bypass

Last updated May 18, 2021 by Alan Bavosa

Learn 3 easy steps to Protect iOS Apps against FlyJB and other Jailbreak bypass tools found on Cydia.

What is FlyJB?

FlyJB is a jailbreak bypass tool that allows users to bypass in-app jailbreak detection mechanisms. It also claims to allows bypassing the built-in DRM of App Store applications to prevents 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.

Keep reading to learn how to use Appdome Jailbreak Prevention to protect any iOS app against FlyJB and other Jailbreak bypass tools.

What is iOS Jailbreaking?

Jailbreaking is the process of unlocking the iOS operating system on an Apple mobile device. Jailbreaking 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).  Jailbreaking is often accomplished by exploiting bugs in Apple’s software/firmware or modifying system kernels to allow read and write access to the file system. Jailbreaking is one of the primary methods/tools for every hacker – both black hat hackers and white hat hackers (eg: penetration testers or security researchers). They all use Jailbreaking in similar ways (to compromise the security model of mobile devices, the operating system, and any app running on the device). The main difference is that black hat hackers have malicious intent, while white-hat hackers generally have non-malicious intent.

What is Jailbreak Bypass (aka Jailbreak Hiding)?

Hackers use Jailbreak Bypass and Jailbreak Hiding tools to evade Jailbreak detection/protections. As mentioned above, 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. If they can evade detection, then they can operate in a Jailbreak state longer (doing whatever activity they used Jailbreak to achieve in the first place): such as play the game for free longer, or use more advanced or automated tools like emulators to modify in-app purchases, use FRIDA to inject malicious code, to use IDA-Pro to create a call graph to trace the app’s source code, to modify app workflows, or send fake signals to unsuspecting users to make their attacks seem more legitimate/credible.

Hackers combine Jailbreak tools with Jailbreak bypass tools to kill two birds with one stone. For example, hackers combine the use of Jailbreak tools like CheckRa1n,Unc0ver, Zylon, PlankFilza, Chimera, etc, (which they use to Jailbreak iOS), alongside special-purpose Jailbreak Bypass or Jailbreak hiding tools like FlyJB, Liberty Lite and others, which they use to bypass jailbreak detection. The first set of tools is used to achieve Jailbreak state, while the second set of tools is used to conceal the fact that the device is Jailbroken or to bypass Jailbreak protection/detection mechanisms in the app.

Bottom line: Jailbreaking compromises the mobile security model. It enables hackers to send fake signals, to modify code, to modify the file system, to disable security protections. Any iOS app that runs on a Jailbroken device is in a vulnerable state, where hackers can amplify and increase the magnitude of their attacks.

How to Protect iOS Apps against FlyJB Jailbreaking Bypass Tool

Appdome Jailbreak Prevention enables an iOS app to protect itself against FlyJB Jailbreaking bypass. You can use Appdome to build Jailbreak Prevention into any iOS app – without coding. When the Appdome-secured app detects that it’s running on a Jailbroken device the app will shut itself down (default behavior) after displaying a message to the mobile user. This protects that app, user, and mobile data from being compromised or attacked by a malicious actor using Jailbreaking.

3 Easy Steps to Protect iOS apps against FlyJB and other Jailbreak bypass tools found on Cydia  

Please follow these 3 easy steps to add Jailbreak Prevention to any iOS app and prevent hackers from using FlyJB to bypass Jailbreak detection. 

  1. Upload an iOS App to Appdome’s no code security platform (.ipa)
  2. In the Build Tab, under Security, Select Jailbreak Prevention (shown below)
  3. Click Build My App

No code jailbreak prevention ios apps

Congratulations! The app can now defend itself against FlyJB and other Jailbreak bypass tools.

Appdome’s no-code mobile app security platform offers mobile developers, DevSec and security professionals a convenient and reliable way to protect Android and iOS apps with RASP (Runtime Application Self-Protection), such as Jailbreak Prevention. When an Appdome user clicks “Build My App,” Appdome leverages a microservice architecture filled with 1000s of security plugins, and an adaptive code generation engine that matches the correct required plugins to the development environment, frameworks, and methods in each app.


Here’s what you need to build secured apps with Jailbreak Prevention to protect against FlyJB and other Jailbreak bypass tools found on Cydia.

No Coding Dependency

Using Appdome, there are no development or coding prerequisites to build secured apps with Jailbreak prevention. There is no SDK and no library to manually code or implement in the app. The Appdome technology adds the relevant standards, frameworks, and logic to the app automatically, with no manual development work at all.

How to Sign & Publish Secured Mobile Apps Built on Appdome  

After successfully securing your app using Appdome, there are several available options to complete your project, depending on your app lifecycle or workflow. These include 

Or, see this quick reference Releasing Secured Android & iOS Apps built on Appdome. 

 How to Learn More

Check out the following related KB articles:

Jailbreaking Prevention

Rooting Android 

Prevent Jailbreak Bypass and Jailbreak Hiding 

Check out the full menu of features in the Appdome Mobile Security Suite

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

Or request a demo at any time.

Thank you!

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