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LEARN TO CRACK BASIC J2ME APPLICATIONS WITH PHONE
Cracking J2ME applications is very easy if you understand Java. You don't need much understanding of Java to crack simple J2ME applications, but it helps a lot when it comes to very complex codes. Understanding Java is just not enough to crack J2ME applications, but you need to be creative as well. I must say that, "creativity rules in every trade".
MAIN OBSTACLES TO CRACKERS
OBFUSCATIONThe main obstacle to crackers is the intervention of obfuscation tools. Obfuscators are tools that are used to make Java source codes very complex for crackers like us, though this wasn't the main intention for developing obfuscators. They were originally developed to reduce bytecode size. What obfuscators do is to rename variables, methods and even class names to confusing names usually made of invalid characters. This sometimes make decompilation imposible. Obfuscation can also encode strings in the code and as well remove unused method names and variables.
ENCRYPTION
This can be done manually in the source code to encrypt sensitive parts of the code such as strings and security codes.
Obfuscation and encryption makes things extremely difficult for crackers and discourage them from attempting to crack such applications.
Obfuscation and encryption however, does not make a code or application 100% secure from being cracked.
Infact, it takes a determined and motivated cracker to compromise an obfuscated and encrypted code.
WHAT CRACKING DEMANDS
Cracking demands the following:
=> Patience
=> Determination
TOOLS OF THE TRADE
This tutorial is exclusively for mobile phone users and are therefore to be done on phone. You will need the following tools:
jClazzME
This is a decompiler. Decompilers convert bytecode back to it's high level language called source code. Because Java source codes can easily be read by humans than computers, we call them high level language.
=> Class Hacker- is a bytecode editor with lots of other functions.
=> ByteCode editor: the name says it all. This is also a bytecode editor. It's used to edit bytecode or Opcodes.
Opcodes are instructions that tells the JVM what to do.
=> Class Editor: it's use to edit hex values of class files. It is also a disassembler.
=> MobyExplorer: a file manager and also a text viewer. It has other functions like extracting zip files and also encrypting files in your phone.
=> Blue ftp: is a file manager and also for compressing and extracting various archives.
PROCESS OF CRACKING
In my own way, i think cracking J2ME applications involve four steps. These are:
=> Observation
=> Decompilation and analyzing the code
=> Editing of class files
=> Compressing class files and testing.
In this tutorial, i'm going to use an application called Nestorjava as example. I hope you know about this application which asks for N100 MTN airtime in order to get the activation code. Actually, i don't know the equivalence of N100 in my our currency(Ghana) since i'm a Ghanaian. This application actually doesn't do what it claims to do. After cracking it, you would realize it doesn't perform some of the functions it's developer claims to do. It's just like a toy application...
Before we start, download Nestorjava with UC web and rename it to Nestorjava.zip or which ever way you do it, i don't care. But you must get in a zip format.
OBSERVATION
Observation involves running the trial or demo version of the application and analyzing very carefully its behaviour.
=> Launch Nestorjava. Scroll down and click on "Activate(N100 only)". It will ask you permision to create a call to 08068909105. Just click "No".
=> Now click on "Enter code". Input any code that comes into your mind and click "Activate". You will get an error message saying "Wrong code entered!!! Get the real code with only N100". Take a sheet of paper and copy the above error message exactly as you see it.
=> Exit Nestorjava.
DECOMPILING AND ANALYZING CODE
=> Launch ByteCode editor and open Nestorjava.zip. Now type the error message you copied on the sheet of paper on the search box provided and click "OK". Wait for ByteCode editor to search and extract the particular class file that contain the error message. All rights reserved
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