用修改IAT法HOOK API

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

#define  UNICODE
#define  _UNICODE

 

PIMAGE_DOS_HEADER  pDosHeader;
PIMAGE_NT_HEADERS  pNTHeaders;
PIMAGE_OPTIONAL_HEADER   pOptHeader;
PIMAGE_IMPORT_DESCRIPTOR  pImportDescriptor;
PIMAGE_THUNK_DATA         pThunkData;
PIMAGE_IMPORT_BY_NAME     pImportByName;
HMODULE hMod;

int * addr = (int *)MessageBoxA;        //儲存函數的入口地址
// 定義MessageBoxA函數原型
typedef int (WINAPI *PFNMESSAGEBOX)(HWND, LPCSTR, LPCSTR, UINT uType);
int WINAPI MessageBoxProxy(IN HWND hWnd, IN LPCSTR lpText, IN LPCSTR lpCaption, IN UINT uType);

int * myaddr = (int *)MessageBoxProxy;

int main()
{
        //OutputDebugString(_T("start !"));
        MessageBoxA(NULL, "原函數", "09HookDemo", 0);

        //-------------HOOK部分
        hMod = GetModuleHandle(NULL);

        pDosHeader = (PIMAGE_DOS_HEADER)hMod;
        pNTHeaders = (PIMAGE_NT_HEADERS)((BYTE *)hMod + pDosHeader->e_lfanew);
        pOptHeader = (PIMAGE_OPTIONAL_HEADER)&(pNTHeaders->OptionalHeader);

        pImportDescriptor = (PIMAGE_IMPORT_DESCRIPTOR)((BYTE *)hMod + pOptHeader->DataDirectory[1].VirtualAddress);

        while(pImportDescriptor->FirstThunk)
        {
                char * dllname = (char *)((BYTE *)hMod + pImportDescriptor->Name);
                //printf("函數模組：%s\n",dllname);

                pThunkData = (PIMAGE_THUNK_DATA)((BYTE *)hMod + pImportDescriptor->OriginalFirstThunk);

                int no = 1;
                while(pThunkData->u1.Function)
                {
                        char * funname = (char *)((BYTE *)hMod + (DWORD)pThunkData->u1.AddressOfData + 2);
                        PDWORD lpAddr = (DWORD *)((BYTE *)hMod + (DWORD)pImportDescriptor->FirstThunk) +(no-1);
                       
                        //printf("%4d:  ",no);
                        //printf("%30s",funname);
                        //printf("%8x\n",lpAddr);
                        //printf("%8x\n",*lpAddr);
                        //修改記憶體的部分
                        if((*lpAddr) == (int)addr)
                        {
                                //修改記憶體頁的屬性
                                DWORD dwOLD;
                                MEMORY_BASIC_INFORMATION  mbi;
                                VirtualQuery(lpAddr,&mbi,sizeof(mbi));
                                VirtualProtect(lpAddr,sizeof(DWORD),PAGE_READWRITE,&dwOLD);
                                //寫記憶體
                                WriteProcessMemory(GetCurrentProcess(),
                                                lpAddr, &myaddr, sizeof(DWORD), NULL);
                                //恢複記憶體頁的屬性
                                VirtualProtect(lpAddr,sizeof(DWORD),dwOLD,0);
                        }
            //---------
                        no++;
                        pThunkData++;
                }

                pImportDescriptor++;
        }

        //用於測試的API函數
        MessageBoxA(NULL, "原函數", "09HookDemo", 0);

        getchar();
        return 0;
}

int WINAPI MessageBoxProxy(IN HWND hWnd, IN LPCSTR lpText, IN LPCSTR lpCaption, IN UINT uType)
{
        return         ((PFNMESSAGEBOX)addr)(NULL, "Gxter", "Gxter", 0);
        //用地址調用一個API函數
}