How to Crack Android App - Guide to Reverse Engineer APK

Android apps have become an integral part of our life , allowing you to access almost everything within some touches. Unlike laptops and PCs , android devices are being highly used due to which android apps are being used on a large scale. From interacting to social audiences to Learning something new , android apps provides you a flexible options. In this post , we will learn how to crack (or mod) android apps and will understand the real logic behind the mod apk.

What is Cracked App

As the name suggest , 'crack' means something which is 'broken' , that means in the context of android , those apps whose logic / coding are modified or tampered for achieving a certain goals like for removing 'in-app purchase' and providing you premium features for free , for removing 'in-app ads' and providing you ad-free app , for removing license check that would normally restrict apps from being used or opened. Let's take some examples of these goals , so that you can understand it easily.

in-app purchase

Consider a movie streaming app as an example, which imposes a limitation on watching videos only in 480p resolution. To enjoy high-quality video content, users are required to buy a subscription, and this is known as in-app purchase.

in-app ads

Consider a productivity application that helps you manage your daily tasks or a photo editing app that lets you enhance your images. Many free-to-use apps include 'in-app ads' , which are promotional content displayed within the app interface. These ads can range from banners to full-screen pop-ups and are intended to generate revenue for the developers. However, these ads can sometimes foil the user experience.

license check

Suppose your friend has purchased an app from play store (paid app). If he shares that app to you via any medium , let's say through bluetooth or any sharing app , the app will not run in your device by stating that 'license not found'. This license check is designed to ensure that only individuals who have legitimately purchased the app from official app stores can utilize it

Who crack android apps

Android app cracking is typically carried out by individuals with programming and reverse engineering skills, as well as those who possess a thorough understanding of the Android operating system's architecture. These individuals are commonly referred to as "crackers" or "reverse engineers."

How to crack android app

So i think , you got some knowledge about android apps and why to crack android apps. Let's start learning how to crack android apk. To crack android apps , certain prerequisites need to be fulfilled. These requirements include :

Windows OS ( You can choose any other os , but let's stick with windows in this tutorial )
APK Easy Tool - It is a gui based tool to decompile , compile , sign android apps. Java must have installed on your system along with .NET Framework.
APKTool - APKTool is a powerful tool used for reverse engineering Android apps. It allows you to decompile and recompile APK files, enabling you to analyze and modify the app's code, resources, and functionalities. If you are using APK Easy Tool, you can skip using APKTool as APK Easy Tool integrates APKTool's features, providing a more user-friendly graphical interface for app modification.
Visual Studio Code - It is a powerful code editor , will be used in modifying source code
SMALI code understanding - Smali code is generated by decompiling Android apps from their compiled form (APK files) back into a human-readable format. It is necessary to understand smali codes in order to crack android apps.
Patience - Most important :)

So , after you have completed all of these prerequisites , let's know process of modding apk.

Process of cracking android app

The first step is to decompile our target app. For this purpose , we can use APK Easy Tool or APKTool. You just need to browse the target apk into APK Easy Tool and click on 'Decompile' button. After completion of decompilation process , a decompiled directory will be made consisting of some important directory.
Browse the decompiled folder in VS Code. Our target folders will be 'smali' , 'smali_classes2', 'smali_classes3' like that. These directories hold the app's code.
Analyze the code and modify as per as the requirement. For this you must have 'aim" and you should have to modify correct piece of code . For this 'smali' knowledge is important. For example : if-eqz p0, :cond_101 , that means if value of p0 is '0' then goto place :cond_101 , so in this case , comment out the line , or delete the line or make the value of 'p0' as 1 (not 0).
Also , you can analyze the functions or methods or classes which are responsible for certain action. You can analyze and remove the calls to those functions and methods or classes.
Strings plays an important roles and sometimes it provides you an important clue to right place. Make sure to analyze them also. Mostly the String are present in resources.
There are smali instructions used for conditional branching. 'if-eqz' means "if equal to zero", and 'if-nez' means "if not equal to zero". So try to clear your concept of smali. Note that you cannot modify 'java' codes of decompiled app. You can only convert smali into java for better understanding using some tools , but when it comes to modify code , you have to perform this in smali only.
After modification , compile the decompiled folder using APK Easy Tool.
After the app is compiled, it's important to sign and align it properly before installing it on a device. Signing : Android apps must be signed with a digital certificate to ensure their authenticity and integrity. You can sign the app using a tool like "Sign APK" within Apk Easy Tool. You will need a valid keystore file and its corresponding password. If you don't have a keystore, you can create one using Java's keytool utility. Or you can use inbuilt keystroke of APK Easy Tool. Zipaligning : Zipalign is an optimization process that improves the app's performance on Android devices. It aligns the app's data in a way that allows the operating system to access it more efficiently. You can use the "Zipalign" tool within Apk Easy Tool to perform this step.
Your 'cracked' app is ready to use. Test it in android device or android emulator.

FAQ

App is not getting installed after modding.

This issue may be arised due to error in compilation process.

App crashes on launching or random crashes occur.

It may have several reasons. You may have made syntax or coding error in smali codes or there is signature check in app. Signature check is a process of checking the app's signature with developer's signature. If we modify any apps and sign it , it's signature gets changed. So we need to bypass the signature check.

How to get .apk file

There are several ways to get .apk file , You can extract your installed app using your file manager to obtain its .apk or you can download .apk from apkpure or apkcombo.

How to mod Netflix apk

Netflix is a server sided application hence it can't be modified. The core functions are managed on remote servers, attempting to modify the app's code on a client device won't have a direct impact on the functionalities of app.

Is it is safe to download mod app

No , as most of them contain virus.

Premium features still not unlocked

After modification , if the app's premium features are not unlocked that means you have not modded it correctly and the app must have some more checks in it.

Disclaimer

Please note that this tutorial is designed purely for educational purposes. It does not endorse or support any illegal activities, such as modifying apps, infringing on copyrights, or violating terms of service agreements. The content here aims to educate users about the technical mechanics of app cracking and reverse engineering. It's crucial to respect developers' rights, abide by legal regulations, and uphold ethical conduct in the digital domain. This tutorial does not provide guidance on unauthorized app modification or the use of cracked apps, both of which could lead to legal repercussions and security vulnerabilities. Readers are encouraged to maintain responsible and lawful digital practices.

Narendra Dwivedi