A simple step by step tutorial with amazing visuals on how to reverse engineer an Android apk file. Leave your comments below if any. thanks -biwin

1. #AndroidHacks
Extract Soucre Code from an
Android APK file
© CambakLabs

2. Biwin John | @xkaterboi

3. disclaimer
This presentation is intented only for educational puropose . Any actions and/or activities
related to the information contained in the presentation is solely your responsiblity. The
misuse of the information in this presentation/file may result in criminal charges brought
against the person in question. THE AUTHOR AND ANY AUTHORITY(IES) RELATED WITH THIS
PRESENTATION WILL NOT HOLD ANY RESPONSIBILITY IN ANYCASE FOR YOUR ACTIONS. Do not encourage
to use this information to hack/crack any applications.

4. inspiration
“
”
THE HARD DRIVE ON MY LAPTOP
JUST CRASHED AND I LOST ALL THE SOURCE
CODE FOR AN APP THAT I HAVE BEEN WORKING ON
FOR THE PAST TWO MONTHS (I KNOW I AM AN IDIOT FOR NOT
BACKING IT UP) ALL I HAVE IS THE APK FILE THAT IS STORED IN MY EMAIL
FROM WHEN I SENT IT TO A FRIEND. MY QUESTION IS:
IS THERE ANY WAY TO EXTRACT MY SOURCE CODE FROM
THIS APK FILE? I REALIZE THAT IS IS MOST LIKELY
A SHOT IN THE DARK... BUT I AM REALLY DESPERATE.
asked on stackoverflow.com by Frank Bozzo,
© 2013 Stack Exchange Inc

5. What We’re gonna do now?
> Extract the Source code and resources from an
android application package (.apk) file.

6. The tool kit
> a valid apk file
> dex2jar ¹
> java decompiler ²
> apktool ³
> apktool installer 4
¹ http://code.google.com/p/dex2jar/downloads/detail?name=dex2jar-0.0.9.9.zip
² http://www.4shared.com/zip/MIIaULpa/jd-gui-033windows.html
³ http://code.google.com/p/android-apktool/downloads/detail?name=apktool-install-windows-r04-brut1.tar.bz2
4 http://code.google.com/p/android-apktool/downloads/detail?name=apktool1.4.1.tar.bz2&can=2&q=

7. lets get started

8. Step 1
Download all the files in the toolkit and the desired apk,
move them to a directory.

9. Step 2
Rename the desired apk to zip. eg: myapp.apk to myapp.zip

10. so here’s
how
to show
the filetypes
in windows 7

11. Step 3
Extract myapp.zip to a new folder.
use archiving apps like
7zip, WinRAR etc.

12. Step 4
after the extraction, rename myapp.zip back to myapp.apk.

13. Step 5
Extract all the downloaded files to the same directory.

14. Step 6
move all the extracted files to the myapp directory.

15. Step 7
now our playground, myapp dir must look something like this.

16. the application files are extracted now but they are hexcodes,
just machine readable, manifest.xml just reads like this.

17. Step 8
Open the windows command prompt. WinKey + R type ‘cmd’
inside the dialogue box, press Enter.

18. Step 9
Navigate cmd to the folder that you are working on.
‘cd’ <dir name> changes directory
‘cd ..’ navigate to the top level (back)
‘dir /w’ list the files by just names
here I’ve used
cd downloadstestmyapp
as my ‘myapp’ folder inside the directory
named ‘test’ inside the ‘downloads’ dir.

19. Step 10
type the command "dex2jar classes.dex" and press enter. This
will generate "classes.dex.dex2jar" file in the same folder.

20. Step 11
double click to open the java decompiler (jd-gui.exe)
shows the file ‘jd-gui.exe’
and the ‘classes_dex.jar.jar’
created by the
previouscommand

21. Step 12
Open the jar file, browse for ‘classes_dex.jar.jar’ click open.

22. Step 13
Select save all sources, make a folder ‘sources’ in myapp then
click save. Extract the Zip file in sources to get souce files

23. A Java class
Just Extracted
New Born:

24. Step 14
Now lets extract the xml files
on the command line type ‘apktool if framework-res.apk’ press enter.
//this should result in ‘Framework installed’

25. Step 15
on the command prompt type ‘apktool d myapp.apk’ (where
myapp should be replaced with the apk name).

26. This creates a folder named myapp inside our working folder
which contains all the xml files of the app.

27. the manifest.xml
file just generated.
Decoded:

28. okay now we are almost done,
move the folder ‘sources’ to the folder myapp

29. HAVE FUN WITH
ANDROID.
RESCPECT OTHER
DEVELOPERS

30. Questions?
Twitter: @xkaterboi

31. thanks for watching!

32. @xkaterboi©CambakLabs
Biwin John