De-Compiling Android Application

De-compiling Android Application

All applications for Android phones are distributed as APK Files. These files contain all the source,UI , images and other media necessary to run the application on your phone.

The decompilation process isn’t perfect and the code you get won’t reflect the original code 100%. Things like variable names, loop structures and anonymous inner classes might be interpreted differently especially if the application will obfuscate your code.

• Getting the APK File
• Download the apk file from net of fetch it from the android phone

• This command gives the list of installed apk files with associated path

   
  
   adb shell pm list packages -f -3 
  
   

  • This command will get the apk file on the PC

  
   adb pull /data/app/programming.apk 
  
   

  • Change file extension to .zip

  
   cp programming.apk programming.zip
  
   

  • Extract the contents of the file

  
    unzip programming.zip 
  
    

• Decompiling the code
  • Download dex2jar utility

• Get the classes.dex file unzipped contents

  
   ${PATH}/dex2jar/d2j-dex2jar.sh classes.dex 
  
   

This will convert the dex to jar file and output will result in classes_dex2jar.jar file.

• Download java decompilers like jd-gui or Luyten

• Open decompiler gui and open the jar file
  For Lyuten type the command

  
   java -jar luyten.jar 
  
   

  you will be able to view all the sources of project,external jar files etc.

  • Save the source file

• Select option File -> Save All Sources This will save all the files on the file system.

At this point the sources have been decompiled but not the resources etc

• Decompiling Resources
  • Download the latest version of apktool which is a tool for reverse engineering APK files. This tool dissassembles the code in Smali format along with resources . We will user only resources obtained from this utility as java file had been obtained from earlier approach.

  	
    java -jar apktool_2.0.0rc4.jar d programming.apk
  	
    

  This will create programming folder containing source and resource files

At this point we have recovered both the source and resource files.