.NET Crackme/Reverseme Thread

[Seifer]

Creating this thread because I have made a handful of Reverseme's for Nesox a while back, and I figured I'd share them so everyone can possibly learn a thing or two from them. They're not packed or encrypted (yet, maybe to make it slightly harder in the long run, future ones will be), and reversing them in IDA or something similar should be doable.

If anyone has some reverseme's they've made, send me a PM and I'll stick them into the thread.

KeygenMe - Beginner
Protection: Name and serial protection
Type: Static
Difficulty: Easy
Download: http://dl.dropbox.com/u/10874329/Sim...NET-3.0%29.rar

KeygenMe - Intermediate
Protection: Serial protection
Type: Dynamic - Machine specified
Difficulty: Intermediate
Download: http://dl.dropbox.com/u/10874329/Int...teKeygenMe.rar

KeygenMe - Intermediate 2
Protection: Username and token
Type: Dynamic
Difficulty: Intermediate
Download: http://files.aevitas.in/Intermediate2.rar

Have fun! And if you crack them, SS or it didn't happen.

[suicidity]

Intermediate is too Easy

[Spoiler][/Spoiler]

and a keygen for the Intermediate
[Spoiler]

namespace Keygen
{
	class Program
	{
		[STAThread]
		static void Main(string[] args)
		{
			ManagementObjectCollection Processor = new ManagementClass("win32_processor").GetInstances();
			string CPU = "";

			foreach (ManagementObject Object in Processor)
			{
				CPU = Object.Properties["processorID"].Value.ToString();
				break;
			}

			string Serial = "";
			for (int i = 0; i < CPU.Length; i++)
			{
				Serial = Serial + CPU.Substring(i) + "0";
			}

			System.Windows.Forms.Clipboard.SetText(Serial);
			Console.WriteLine(Serial);
			Console.ReadLine();
		}
	}
}

[/Spoiler]

[RedArray]

I don't know how this is supposed to be a challenge at all if you are just giving us unprotected .NET executables meaning we can simply open them with something like .NET reflector and grab the code...

[SPOILER]

[/SPOILER]

[XTZGZoReX]

Try smartassembly for an actual challenge.

[suicidity]

All posts after mine (intermediate post's because easy is.. well stupidly easy) are invalid unless you provide how you did it; I already gave a valid way to win at it, screenshots don't count anymore.

[RedArray]

All posts after mine (intermediate post's because easy is.. well stupidly easy) are invalid unless you provide how you did it; I already gave a valid way to win at it, screenshots don't count anymore.

Actually you didn't. You provided a key that works with your cpu. Take a good look at the key in your screenshot and the key in mine. They are different. Here I will even post my key so you can compare them easier.

BFEBFBFF000006FB0FEBFBFF000006FB0EBFBFF000006FB0BFBFF000006FB0FBFF000006FB0BFF000006FB0FF000006FB0F000006FB0000006FB000006FB00006FB0006FB006FB06FB0FB0B0

If you are gonna act high and mighty know what you are talking about beforehand.

Just saying.

[Seifer]

I don't know how this is supposed to be a challenge at all if you are just giving us unprotected .NET executables meaning we can simply open them with something like .NET reflector and grab the code...

Yes, Reflector and Dis# and similar programs make it fairly simple, while IDA decompiles it into CIL, which is a step up from that.
I'll be creating a few more with stuff like a packed executable with either Themida or {SA} (even though {SA} is de-obfuscated fairly easily) with server side authentication, so you'll have to go out of your way a bit more.

And I never claimed the intermediate stuff was hard, but simple was meant to be .. really, really simplistic.

ps. {SA} isn't really a challenge either.

// Edit

Uploaded a "teaser", it's a packed assembly with custom protection. Have fun working around it, this should be more "intermediate" as requested.

[suicidity]

Actually you didn't. You provided a key that works with your cpu. Take a good look at the key in your screenshot and the key in mine. They are different. Here I will even post my key so you can compare them easier.

BFEBFBFF000006FB0FEBFBFF000006FB0EBFBFF000006FB0BFBFF000006FB0FBFF000006FB0BFF000006FB0FF000006FB0F000006FB0000006FB000006FB00006FB0006FB006FB06FB0FB0B0

If you are gonna act high and mighty know what you are talking about beforehand.

Just saying.

and a keygen for the Intermediate
[Spoiler]

namespace Keygen
{
	class Program
	{
		[STAThread]
		static void Main(string[] args)
		{
			ManagementObjectCollection Processor = new ManagementClass("win32_processor").GetInstances();
			string CPU = "";

			foreach (ManagementObject Object in Processor)
			{
				CPU = Object.Properties["processorID"].Value.ToString();
				break;
			}

			string Serial = "";
			for (int i = 0; i < CPU.Length; i++)
			{
				Serial = Serial + CPU.Substring(i) + "0";
			}

			System.Windows.Forms.Clipboard.SetText(Serial);
			Console.WriteLine(Serial);
			Console.ReadLine();
		}
	}
}

[/Spoiler]

Yes, because that wouldn't generate you a serial to work with your CPU; If you're going to act like a jack ass and fail troll, do it right.

Just saying.

[RedArray]

Meh didn't even see that. But I said how I solved it.

[suicidity]

I divided by 0?

[Spoiler][/Spoiler]

[SKU]

Cool, always enjoyed solving these [the easy ones at least :P]. Great idea, Seifer!

[streppel]

i just tried the last one and failed really hard
are there any tutorials that will help me understand it better?
thanks in advance

[homer91]

These are cool.
moar please ^^

[RivaLfr]

SimpleKeygenme.exe
[Spoiler]Hank Johnson
239R8Y2W9FSQG129E1YWQDS[/Spoiler]

IntermediateKeygenMe.exe

[Spoiler]
Key for my computer:
BFEBFBFF0001067A0FEBFBFF0001067A0EBFBFF0001067A0BFBFF0001067A0FBFF0001067A0BFF00 01067A0FF0001067A0F0001067A00001067A0001067A001067A01067A0067A067A07A0A0

KeyGen source code:

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;

namespace ConsoleApplication2
{
    class Program
    {
        static void Main(string[] args)
        {
            Console.WriteLine(Token);
            Console.ReadLine();
        }

        static string Token
        {
            get
            {
                string cPUSignature = GetCPUSignature();
                string token = string.Empty;
                for (int i = 0; i < cPUSignature.Length; i++)
                {
                    token = token + cPUSignature.Substring(i) + "0";
                }
                return token;
            }
        }
        static string GetCPUSignature()
        {
            string cPUSignature = string.Empty;
            System.Management.ManagementObjectCollection instances = new System.Management.ManagementClass("win32_processor").GetInstances();
            foreach (System.Management.ManagementObject o in instances)
            {
                if (cPUSignature == "")
                {
                    return o.Properties["processorID"].Value.ToString();
                }
            }
            return cPUSignature;
        }

    }
}

[/Spoiler]

Intermediate2.exe
[Spoiler]
Cracked version: MEGAUPLOAD - The leading online storage and file delivery service

Use a script php for test the login and token: http://account.aevitas.in/reverseme....ME&token=TOKEN

How to crack Intermediate2.exe:

Go to offset with winhex: E80F
Change: 2D 30 By: 2C 30
[/Spoiler]

[wowsc4p3]

All of them were easy but intermediate 2 lolz, i just disassembled the first two but that one is obfuscated