I'm now on analyzing device driver binary. I had wrote code like below:
CreateFileA("\\\\.\\device_name", GENERIC_READ | GENERIC_WRITE, 0, NULL, OPEN_EXISTING, FILE_ATTRIBUTE_NORMAL, 0);
What I got from CreateFileA() returns was INVALID_HANDLE_VALUE(0xFFFFFFFF), without UAC. When I run same code with UAC authenticated It works great, it gave me valid handle.
I've heard the permission for accessing device driver is decided by device type argument of IoCreateDevice(). I checked it but the driver type was FILE_DEVICE_UNKNOWN(0x22), It can be accessed by not only Administrator but also other users. but I failed.
thus I've got frustrated. Am I thinking wrong? Why did i fail on CreateFile()? Could anyone help me?
Thanks for reading. Have a good day.