Learning by hacking - android application hacking tutorial
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The document is a tutorial on Android application hacking by Landice Fu, covering concepts such as Java knowledge, Android app design, and using tools like apktool and smali. It emphasizes responsible usage for educational purposes and includes techniques for localization, decompiling, and reverse engineering. The content also highlights strategies for protecting applications against hacking and provides insights into modifying applications.
![xxxxx!Free
Localization Demo
❖ You don’t even need to know how to
write android app or JAVA!
!
❖ Android multi-language support
mechanism [1][2]!
!
[1] http://developer.android.com/training/basics/supporting-devices/languages.html! !
[2] http://jjnnykimo.pixnet.net/blog/post/37831205-android%E5%A4%9A%E5%9C%8B%E8%AA
%9E%E8%A8%80%E8%B3%87%E6%96%99%E5%A4%BE%E5%91%BD%E5%90%8D
%E6%96%B9%E5%BC%8F](https://image.slidesharecdn.com/learningbyhacking-androidapplicationhackingtutorial-141214092757-conversion-gate02/85/Learning-by-hacking-android-application-hacking-tutorial-10-320.jpg)
Learning by hacking - android application hacking tutorial
- 1. Learning by Hacking Android application hacking tutorial Landice Fu! rusty.flower@gmail.com
- 2. About me Landice Fu Android system developer at ASUS! ! FOSS user and promoter! ! Android app hacker! ! Ruby / JAVA / C / Qt
- 3. Android application hacking tutorial Background Knowledge ❖ Java! ❖ Android Application Design! ❖ Using Android Logcat with Android Debug Bridge (ADB)! ❖ Assembly syntax
- 4. My proclamation about this presentation ❖ The application binary and decompiled code I use in this presentation are only for teaching and learning! ! ❖ After the presentation, I would not provide or use them in ANY circumstances and I will immediately delete them
- 5. You must be really bad! ❖ Pirate! ❖ Stealing accounts and data! ❖ Mess up the device! ❖ BitCoin mining using others’ device
- 7. What about… ❖ UI Localization! ❖ Ad. removal! ❖ Resource extraction! ❖ Wow, that’s cool! How did you do that?! ❖ Fix the bug yourself! ❖ Get to know your enemy and how to better protect your product! ❖ Add some features to it Are you kidding?
- 9. APKTOOL ❖ https://code.google.com/p/android-apktool/! ❖ Command line tool for disassembling/assembling APK! ❖ Decompile APK apktool d file_name.apk! ❖ Rebuild APK apktool b folder_name
- 10. xxxxx!Free Localization Demo ❖ You don’t even need to know how to write android app or JAVA! ! ❖ Android multi-language support mechanism [1][2]! ! [1] http://developer.android.com/training/basics/supporting-devices/languages.html! ! [2] http://jjnnykimo.pixnet.net/blog/post/37831205-android%E5%A4%9A%E5%9C%8B%E8%AA %9E%E8%A8%80%E8%B3%87%E6%96%99%E5%A4%BE%E5%91%BD%E5%90%8D %E6%96%B9%E5%BC%8F
- 11. Localization Demo ❖ Get the original APK! ❖ AndroidAssistant (backup)! ❖ /data/app/ (root access)! ❖ Copy values folder to values-zh-rTW! ❖ Localize the content of values-zh-rTW/strings.xml! ❖ Build and sign the APK
- 12. Smali/Baksmali ❖ Assembler/disassembler for the dex format used by Dalvik! ❖ The syntax is loosely based on Jasmin’s dedexer's syntax! ❖ Supports the full functionality of the dex format! ❖ Annotations (@Override, @SuppressWarnings …)! ❖ Debug Information! ❖ Line Information! ❖ Etc.! ❖ https://code.google.com/p/smali/
- 13. Dalvik opcodes ❖ Write a simple application and decompile it and see how it is turned into Dalvik operations! ❖ http://pallergabor.uw.hu/androidblog/dalvik_opcodes.html! ❖ http://www.netmite.com/android/mydroid/dalvik/docs/ dalvik-bytecode.html
- 14. Types in smali Smali JAVA Primitive Type V void - can only be used for return types Z boolean B byte S short C char I int J long (64 bits) F float D double Class Object Lcom/lansion/myapp/xxxparser;
- 15. Framework Resource ❖ Some code and resources that are built into the Android system on your device! ❖ /system/framework/framework-res.apk! ❖ Installing framework resource for apktool apktool if framework-res.apk
- 16. Integrated Development Hacking Environment
- 17. Virtuous Ten Studio (VTS) ❖ Integrated Reverse Engineering Environment for APK! ❖ Built-in ApkTool, ADB, Zipalign, Sign, dex2jar…! ❖ Support for APKs and framework JARs! ❖ Text editing of smali, xml files with syntax highlighting, live checking and code folding! ❖ M10 file editing (HTC Sense)! ❖ Unpack/ repack boot images! ❖ Generate JAVA sources using multiple libraries! ❖ http://virtuous-ten-studio.com/
- 18. Demo: Remove the ad. from xxxxx!free ❖ What you need! ❖ Know the API of libraries! ❖ Know the API of Android! ❖ Luck! ❖ Patience! ❖ Tip1 : When you don’t know how to do something in smali, just write it in JAVA and decompile it
- 19. Source Obfuscation ❖ Make it really difficult for human to understand and time consuming to hack! ❖ Make the names of variables, methods, classes and packages meaningless! ❖ Remove debug information! ❖ Complicated call flow! ❖ Redundant source code! ❖ …………..! ❖ Penalty of obfuscation Stop laughing…! This is you!!
- 22. Build your own crack tool ❖ Provide static functions! ❖ Add logcat logs with variable states! ❖ Add stack trace dump! ❖ Do the complicated tricks out side of the original program (much easier in JAVA)
- 23. A more difficult task - ??????? ❖ UI is always the key to find the starting point! ❖ Resource ID (name) turns into constant value map! ❖ Insert the snippets decompiled from your crack tool! ❖ Most of the local license checking is not too complicated! ❖ Altering one of the boolean-returning function does the trick in a majority of cases
- 25. Still a piece of cake ❖ Knowing the system API is very helpful! ❖ More complicated check might involve getting IMEI, MAC… from your device! ❖ You still can trick the application by replacing the system API call to your own function
- 26. What I did to Age of Empires on Android ❖ Modify the menu bar to provide control interface! ❖ TCP server to communication with another Android device with the same hacked APK! ❖ Add a robot state machine to get money, resource… from the other account without effort.
- 27. Protect your work ❖ Design with NDK! ❖ Using framework like cocos2d (generates native library)! ❖ Don’t just use one method for checking! ❖ Strong obfuscation! ❖ Provide the content using web! ❖ Find a way to mess up the decompiler
- 28. What you might be interested in ❖ You can use the decompiled code from other apps in your application! ❖ Embed a broadcast receiver to interact with external application
- 29. Thanks for your attention