ZwQueryInformationProcess_ProcessDebugFlags.cpp

#include<windows.h>
#include<stdio.h>

typedef DWORD (WINAPI *PFZWQUERYINFORMATIONPROCESS) (
	HANDLE		ProcessHandle,
	DWORD		ProcessInformationClass,	// Origianl : _PROCESS_INFORMATION_CLASS
	PVOID		ProcessInformation,
	ULONG		ProcessInformationLength,
	PULONG		ReturnLength
);

BOOL anti_debug()
{
	BOOL result = FALSE;
	DWORD fRet;
	DWORD ProcessDebugFlags;

	PFZWQUERYINFORMATIONPROCESS pfZwQueryInformationProcess;
	HMODULE h_ntdll = GetModuleHandle("ntdll.dll");
	pfZwQueryInformationProcess = (PFZWQUERYINFORMATIONPROCESS)GetProcAddress(h_ntdll, "ZwQueryInformationProcess");
	fRet = pfZwQueryInformationProcess(GetCurrentProcess(), 0x1f, &ProcessDebugFlags, 4, 0);	// 0x1f : ProcessDebugFlags
	if(!ProcessDebugFlags) result = TRUE;	// 3번째 인자 전달 값 확인
	return result;
}

int main(int argc, char **argv)
{
	if(anti_debug())
		printf("Debugger Detected\n");
	else
		printf("No Debugger...\n");
	return 0;
}