How to patch .NET DLLs?

[Newbie_Cracker]

SystemeD
I patched byte you've shown and sent patched DLL to my friend to test it.
This time .NET compiler said : "Invalid program" (or something like this).
May its because of joining your method and method of patching 80 at offset 102C.

Tonight, I played with a simple file compiled with and without Strong Name. I noticed after compiling with KEY, 80 A0 and PublicKey are the major differences between two files. So my suggestion is : Patching whole PublicKey and 2 bytes before it to 00.

I must test it again.

And...
Present version of ILDASM (.NET SDK 1.1) crashes at decompiling time and the produced file is uncompilable. Do you decompile and recompile the mentioned dll successfully?

[SystemeD]

Originally Posted by newbie_cracker

I patched byte you've shown and sent patched DLL to my friend to test it.
This time .NET compiler said : "Invalid program" (or something like this).
May its because of joining your method and method of patching 80 at offset 102C.

It's exactly what you have to do. I checked it again and it works. Be carefully because the code I posted may be different from yours (you have to look at the position of the bytes), because I downloaded the latest version of the app for testing.

Originally Posted by newbie_cracker

Tonight, I played with a simple file compiled with and without Strong Name. I noticed after compiling with KEY, 80 A0 and PublicKey are the major differences between two files. So my suggestion is : Patching whole PublicKey and 2 bytes before it to 00.

Probably it would work too, I didn't try it...

Originally Posted by newbie_cracker

Present version of ILDASM (.NET SDK 1.1) crashes at decompiling time and the produced file is uncompilable. Do you decompile and recompile the mentioned dll successfully?

In my previous post I talked about future versions, try ILDASM from SDK 2.0 Beta...

PS: I suggest you to patch only the strong name infos at first. Test if the assembly works and after apply all other cracking patches.

[jjhsd]

what i have encoutered is ildasm does work, but the output file it produces contains a lot of ascii characters(not a-z). then ilasm will have problem to compile it back.

[SystemeD]

Can you point me to your target?

[jjhsd]

RedGate SQL Bundle - "RedGate.Licensing.Client.dll"

i ran ildasm, dumped everything. then couldn't compile it back (without changing any il code)

hxxp://www.red-gate.com/downloads/bundle.exe

Have you read this?

http://www.codeproject.com/dotnet/#Security

specially:

Building Security Awareness in .NET Assemblies : Part 3 - Learn to break Strong Name .NET Assemblies

-> An example how to break RSA in .NET

It´ll help you to understand how to break[patch] RSA etc. in .Net

[TQN]

Did you try it with Reflector. If in Reflector, you only see garbage function names, member variables, the dll used obfuscation, and ILASM can failed when recompiling.

[jjhsd]

yes, it works. I didn't change resource file name in the dump, that's why it failed.
thank you. : )

[Newbie_Cracker]

Last night I saw a little tool for removing StrongName Signature from .NET applications in Woodman forum.
Little description of this tools is :


SNRemove v1.00
Copyright (c) 2005 Nir Sofer
Web Site: http://www.nirsoft.net


But it didn't fix SN Signature in ASP .NET Applications.
So I created this patcher to solve this for all .NET Applications. It's the result of this topic.

Best regards.

[Unforgiv3N]

Nice Job, Thanks!
NeWBiE_Cracker