Reverse Engineering Android apk

Reverse Engineering Android apk


Table of Contents

  • Background
  • Apktool
  • dex2jar + JD-GUI

1 Background

Here is my puzzle at this moment, my superior gave me a task to make Bluetooth Low Energy product which includes Android APP part, but there are no virtual designer and product manager, just myself as a software engineer.

So, my first step is to found out a similar product and refer its design. Then, I need to decompile that app, some reverse engineering skills of Android app and java are necessary.
I guess following two methods are enough to decompile an Android app.

2 Apktool

ApkTool is a tool for reverse engineering Android apps, what it is pretty good at is to decode resources to nearly original form and rebuild them after some modification. But the java code part is decompiled into the smali format, which is not a good format to read and understand.

3 dex2jar + JD-GUI

Apktool can not generate readable java source code, actually, there are no reverse engineer ways to generate the original source code. The combination of dex2jar and JD-GUI can be a good choice to get a pretty good readable source code from apk file.

dex2jar is a tool to read the dex(Dalvik Executable format) and generate the standard java .class format. The jar file can transport to next pipeline.

JD-GUI can be used to decompile the standard java .class files, which usually be packaged in a jar file, into the readable source code.

Comments

Post a Comment

Popular posts from this blog

Bluedroid stack in android

Image
Bluedroid stack in android Table of Contents Bluetooth stack in android Bluedroid .VS. Bluez Porting guide of Bluedroid stack 1 Bluetooth stack in android From Android 4.2, google use Bluedroid stack as its default Bluetooth host stack, before android 4.2, its default Bluetooth host stack was Bluez, which is also the Linux distribution's default stack. So why google changed its Bluetooth stack? The reason is maybe that Bluez stack was designed for the desktop environment, so in order to port Bluez into android, android must solve some dependency issues, like porting Dbus, Linux desktop's default IPC, into android. So there are at least five processes to power Bluetooth before android 4.2, they are systems, Bluetooth APP, Bluez, hciattach, and Dbus. The damn thing is that there are bugs between them, so Bluetooth stack is the weakest part in the android system before android 4.2, yeah, it is the usual reason that android system corrupted. So, what's t
Read more

How to setup a NAT server?

Image
How to setup an NAT server? Table of Contents What is NAT? How to setup NAT host? a shell script from vbird's book 1 What is NAT? NAT stands for Network Address Transition, which is the basic function of gateway host. I try to hack Bluetooth tethering module in android this week, it include the Bluetooth Pan profile and the NAT setup process, which means in order to implement the Bluetooth tethering, first, two devices must be connected by Bluetooth Pan profile, and then the server part device acted as gateway host to supply the network forward service. In other words, after Bluetooth Pan profile connected, the server must to setup its NAT rules to forward the IP packages. So how to setup NAT rules? 2 How to setup NAT host? My memory is still fresh that at the start of my Linux journey, I setup my Linux desktop as an NAT host to provide Internet services for my lab's classmates. During the days as a programmer, I once did a job to hacking android&
Read more

Network programming in elisp

  Network API in elisp Table of Contents 1 Introduction 2 A example 3 Http server implemented by elisp 1 Introduction Emacs is not just an editor, Yes, that's true. Emacs lisp can do network connection programming by its network API. But there is something difference with other kinds of programming language. First, elisp do not support multi-thread, pretty cool, huh!! Yeh, Multi-threads programming is a horrible venture for you, right! Second, There is no socket similarly conception in elisp, and elisp provide network programming ability as processes. Elisp can open a network connection by function – open-network-stream .  It can make network connection server listen a special port by function - make-network-process . Both of those function return a process object. Then you can communicate with the process by process's API. 2 A example I write a snippet code to figure out How to use it. ( require ' cl ) ( defvar my-network-client-b
Read more