foreword
Android reverse engineering refers to the analysis and research of released Android applications, through reverse engineering, to crack and master the underlying implementation principles, business logic, source code and malicious behaviors of Android applications. Reverse engineering allows researchers to gain an in-depth understanding of the implementation details of Android applications, thereby identifying and repairing vulnerabilities, improving security, and also helping application developers understand the security of their applications.
Usually, the following steps are required to reverse an Android application:
1. Decompilation : decompress the APK file of the Android application into a readable bytecode file to facilitate subsequent research and analysis.
2. Analyze the application code : understand the code in the APK file, including the layout (xml) file, source code, resource file, etc., and study the logic, algorithm and data structure of the application.
3. Knowledge application : tools and technologies for various protection and reinforcement measures, such as code obfuscation, encryption, anti-debugging, etc.
4. Decrypt application data : crack the encrypted data in the application, such as encryption algorithm, key, etc.
Reverse engineering is a very complex and challenging work that requires relevant knowledge and technology, including but not limited to Java, C/C++, assembly language and other underlying languages, as well as an in-depth understanding of the Android operating system, virtual machine and framework work principle. At the same time, the purpose of reverse Android application should also be to improve the security and stability of the application, rather than for illegal purposes.
What about the reverse outlook for Android?
With the popularity of mobile applications and the diversification of usage methods, reverse engineering will become more and more important. Android reverse engineering will become an important technology, so talents with professional skills and experience in the field of reverse engineering will be more and more popular and demanded by the market.
What knowledge points do you need to master in Android reverse engineering?
When it comes to this question, there are probably various answers. A says that you need to learn this, B says that you need to learn that, and C says... In fact, everyone does not have a unified answer. In fact, for friends who want to start learning, Preface Mastering the basics is the most important thing. In order to help everyone firmly grasp the basic knowledge points in Android reverse engineering and the reasonable use of some tools, I had a heated discussion with many Android reverse security engineers who have worked for many years. , and finally sort out the Android reverse and safe learning route reasonably:
Such as Smali instructions, packing and unpacking, Xposed framework, Frida, packet capture, encryption and decryption algorithms, etc., these are the knowledge points that Android reverse security development engineers must master.
As for the study notes, I have organized them based on the knowledge points mentioned above, so that it is more convenient for everyone to learn, and everyone can learn together. Reference method:https://qr18.cn/CQ5TcL
Android reverse security study notes
Android reverse emulator environment construction (detailed explanation)
Smali instruction detailed explanation
Getting Started with Packing and Unpacking
NDK and reverse engineering
Xposed framework
Frida-The Dragon Slaying Knife Reverse Development
Commonly used encryption algorithms for Android reverse
Reference method:https://qr18.cn/CQ5TcL