Introduction to Cracking - (Part I)
 

Introduction

This is my first article here. I hope it would be useful to everyone. Please not that this article is ONLY for educational purposes and in no way I encourage illegal cracking of applications.

Now as this is the first part, I would start with something very basic. Let's start with decompiling -- the process of extracting the source code from the compiled exe. Yes, you heard it right, source from exe ! Let me clear it first that exact decompilation is not possible for many programming languages like C++, VB 6.0 etc.. But there are a few that can be quite satisfactorily decompiled to source-code e.g. Java, .NET (VB, C#, J#, VC++, Delphi.NET), Flash (decompilation from swf to fla) etc...

In this article, I will only talk about decompiling .NET programs (if I get good response then I will continue other decompilation techniques in next parts).

Tools

For decompiling .NET apps, the only tool you need is .NET Reflector. It's an excellent decompiler by Red Gate and best of all, it's available for FREE. You can just google for .NET Reflector by Red Gate and the first result is what you need. You can grab a free copy with some plug-ins which I think are necessary. So, here is a summary of what you need :

Application

1. .NET Reflector by Red Gate
2. The app you want to decompile (let's call it XYZ.exe)

Plugins :

1. Snippy
2. Code Search
3. Reflexil
4. Deblector
5. SilverlightLoader (if you want to decompile Silverlight)

Setup ...

Now, after downloading Reflector, you've to set it up (won't take long).

1. Extract the zip file to any directory you like.
2. Now extract the plugins to the sub-folder "Plugins".
3. Open Reflector.exe and goto View -> Add-Ins.
4. Click "Add..." and navigate to plugins directory.
5. CodeSearch and Snippy come with only 1 dll, so you can add them right away :pleased:.
6. But Reflexil and some others come with multiple dll files. You will have to add the correct dll. For ease, generally they are named in the format "<plugin-name>.dll" or "Reflector.<plugin-name>.dll. E.g. Reflexil's plugin is "Reflexil.dll" and Snippy's is "Reflector.Snippy.dll". So add such files. Adding wrong dlls would result in an error, but Reflector won't crash.

After adding plugins to Reflector, it's ready for you to decompile any .NET app ;).

Decompilation

Before you start decompiling apps, take a look at the small list box below the menu-bar. You can choose the language into which Reflector will decompile the exe. .NET apps built with any .NET language can be decompiled into any other .NET language :).

Now, File -> Open -> <select your exe>. Reflector will decompile it for you !
You get the almost EXACT source-code of the app. Decompilation by Reflector is so exact that sometimes, you can directly copy the code from Reflector and re-build the app !

Possible Uses

1. You have lost the source-code of your c00L .NET app and badly want it back !
2. You want to crack the serial for a software built with .NET. When you get the source, you know how the software expects the serial to be, so you can easily crack it. (Details will be in next part ..)
3. Check if your code obfuscation is good enough to protect it from target users. (I will talk in details about obfuscation in next parts...)

Limitations

Several obfuscation schemes can protect .NET apps from being easily decompiled (but they can't make make it totally un-decompilable ;)). I will talk about cracking some obfuscations in next parts ...

Till then .. take care 'n' good bye.

Thanks for reading this.

Re: Introduction to Cracking - (Part I)
 

Excellent info!! Looking forward to the upcoming parts.

Re: Introduction to Cracking - (Part I)
 

Glad to know that you liked it :smile:.

Next parts will be posted soon.

Re: Introduction to Cracking - (Part I)
 

Nice article, keep them coming!

Re: Introduction to Cracking - (Part I)
 

It's good for a newbie like me, thx... keep going

Re: Introduction to Cracking - (Part I)
 

what does it entail mostly on?

Re: Introduction to Cracking - (Part I)
 

can't wait for the next article on part 1

Re: Introduction to Cracking - (Part I)
 

i loved the part can't wait for the upcoming one

Re: Introduction to Cracking - (Part I)
 

excellent! the best article so far I read on g4e. keep other parts coming regularly..

Re: Introduction to Cracking - (Part I)
 

Thanx everyone for the overwhelming response ! :happy:

I've submitted the Part-II today. I hope you would like that too.

Re: Introduction to Cracking - (Part I)
 

You should have all in one posts :D

Re: Introduction to Cracking - (Part I)
 

mainac = maniac ?!

Just joking, never mind. :D

Re: Introduction to Cracking - (Part I)
 

ya fine

Re: Introduction to Cracking - (Part I)
 

Nomination this Article for Article of the month - May 2009

Re: Introduction to Cracking - (Part I)
 

Vote for this article in Article of the month - May 2009

Re: Introduction to Cracking - (Part I)
 

But the list does not mention it !!! :huh:

Re: Introduction to Cracking - (Part I)
 

I have included the third part which links to Part I and II and so mentioned them here as well that Part III if you liked chances are you like it this one as well.

Re: Introduction to Cracking - (Part I)
 

Oh ! Thanx !! :)

Re: Introduction to Cracking - (Part I)
 

Hmm. None of the Deblector .DLLs are working for me

:thinking:

Re: Introduction to Cracking - (Part I)
 

@ Crump:
Check this : http://stackoverflow.com/questions/4...-use-deblector

Re: Introduction to Cracking - (Part I)
 

Thanks.

Are there any tutorials to making passloads or something on these forums by any chance?

Re: Introduction to Cracking - (Part I)
 

I don't think ...

Re: Introduction to Cracking - (Part I)
 

nice post!
BTW, how can we know a program is created from .NET?

Re: Introduction to Cracking - (Part I)
 

Bravo!

Re: Introduction to Cracking - (Part I)
 

Drag it onto Reflector, it will try to decompile it instantly.
If it fails, the app is not a .NET one :)

Re: Introduction to Cracking - (Part I)
 

that sounds not really effective.
Is there another way to identify it without the 'refletor'?
like we differ someone face.

Re: Introduction to Cracking - (Part I)
 

Another option is to use PEiD ( I mentioned about it in some part II or III of this series. )
It's the *most* effective option.

It works not only for .NET apps, but for all kinds of EXEs, even encrypted, packed ones too.

Download PEiD and use it to examine the exe. If it's a .NET one, PEiD will show "Microsoft Visual C# / Basic .NET". Not only that, it gives loadz of useful info about the exe. :)

Re: Introduction to Cracking - (Part I)
 

ow, thx 4 the info,
I haven't continue to the part 3,
lol...

Re: Introduction to Cracking - (Part I)
 

Hi, I've tried the 'reflector' to crack some exes,
but none success,
maybe they aren't .NET,
can anyone gave one program as example to crack?

I can't find the DLL file of Deblector, what is it named?

Re: Introduction to Cracking - (Part I)
 

> can anyone gave one program as example to crack?
I gave a link to an example crack-me (by w02057) : http://crackmes.de/users/w02057/crac...02057/download in Part-III.
There are tons more at www.crackmes.de

> I can't find the DLL file of Deblector, what is it named?
DeblectorAddIn.dll

Re: Introduction to Cracking - (Part I)
 

Hey bro i liked the article but what is .NET exe. Can we use this method to crack othr formats like game Exe's too.

Thanks

Re: Introduction to Cracking - (Part I)
 

You can use this method to crack .NET games.
Games that are not in programmed .NET, won't be decompiled by Reflector.

But don't expect much, because these tutorials are just for beginners. Cracking games would require considerable knowledge/skill in cracking.

Good luck :)

Re: Introduction to Cracking - (Part I)
 

Excellent...I loved this post a lot. I am looking forward to more posts.

Re: Introduction to Cracking - (Part I)
 

Gr8 tut, bu what can i do with the source of the application?

Re: Introduction to Cracking - (Part I)
 

Even if this is your first article, it seems to be clean in content. Nice to read the article. Thanks for sharing.

Re: Introduction to Cracking - (Part I)
 

nice one bro.. when will you post part-2.................