Simple Keygen Me

[TheCrippledModder]

Difficulty : 2
Language : .NET
Platform : tested on windows 10
OS Version : All
Packer / Protector : Enigma and custom obfuscation (Without constant encryption)

Description : 

So, the goal of this Keygen Me is to obviously create a keygen. Your keygen should create a "KEY" file which will contain data which will be checked by the application. The application takes the key file as input (Drag and drop).

Provided with the application is a sample key file which contains a valid key. Create a keygen which will create other valid key files.

Screenshot :

CrackMe.rar

[puff]

 

Program doesn't even launch for me. . .

 

Edited June 14, 2018 by disterso

[jameswoods]

2 hours ago, disterso said:

 

Program doesn't even launch for me. . .

  

Try adding in a keyfile as an argument, Worked for me..

 

[xSilent]

Wasn't that hard.

1. Dump the assembly.

• Open it in x64dbg
• Break on the entrypoint of clr.dll
• Dump with MegaDumper

2. Deobfuscate it.

• For this I wrote a program that I attached below
• It will deobfuscate the assembly and we can run it/debug it as we please

3. Writing a keygen.

• While I was reversing, I found a formula that makes this really easy:
  • :(1),#{num1}:(2),#{num2}:(3),#{num3}:(4),#{num4}:(5),#{num5}:(6),#{num6}:(7),#{num7}
• You just generate a random string that when you add up the characters of it, you receive 662 as the sum.
• Encrypt it using the Aes thing, just copy paste from dnSpy
• Write it to a file

4. Done

 

UI.: The large filesize of the keygen is due to the music...:) enjoy

Keygen.exe

 

TheCrippledModderDecryptor.exe

Edited October 13, 2018 by xSilent