[系统运维]自己实现GetProcAddress 实战中方便抹掉导入表 自己重建IAT让别人看不到符号

根据导出表实现:GetProcAddress
注意:如果最后出现得函数地址>模块基址+导入表.VirtualAddress得话 则该地址是个字符串 字符串里面有dll和函数名 因为他是个转发地址 需要再调用GetProcAddress去进行获取

GetProcAddress(模块,序号-Base)
1.DWORD dwAddress=(DWORD)AddressOfFunctions[序号]+模块基址;

GetProcAddress(模块,名称)
1.遍历(!strcmp(AddressOfName[i],名称))相等后取出i的下标
2.WORD wOrdinals=AddressOfNameOrdinals[i];
3…DWORD dwAddress=(DWORD)AddressOfFunctions[wOrdinals]+模块基址;

#include <windows.h>
#include
using namespace std;

IMAGE_DOS_HEADER DOS;
IMAGE_FILE_HEADER PE;
IMAGE_OPTIONAL_HEADER OPTIONAL1;
IMAGE_SECTION_HEADER SECTIONS[96];
IMAGE_IMPORT_DESCRIPTOR DESCRIPTOR;
IMAGE_EXPORT_DIRECTORY ExPort;

int  Mystrcmp(char* szBuff1, char* szBuff2)
{
    int nCount1 = 0;
    int nCount2 = 0;
    char* r1 = szBuff1;
    char* r2 = szBuff2;
    while (*r2 != 0)
    {
        if (*r1 == 0)
        {
            r2++;
            nCount2++;
            continue;
        }
        if (*r1 > *r2)
        {
            nCount1++;
        }
        else if (*r2 > *r1)
        {
            nCount2++;
        }
        else
        {
            nCount1++ ;
            nCount2++;
        }
        r1++;
        r2++;
    }
    if (nCount1 == nCount2)
    {
        return 0;
    }
    {
        return 1;
    }
    else
    {
        return -1;
    }
}

FARPROC MyGetProcAddress(
    HMODULE hModule, // DLL模块句柄
    LPCSTR lpProcName // 函数名
)
{
    if (hModule == NULL)
    {
        return 0;
    }
    //DOS
    DWORD Offset = (DWORD)hModule;
    memcpy(&DOS, (char*)Offset,sizeof(IMAGE_DOS_HEADER));
    //PE
    Offset = (DWORD)hModule + DOS.e_lfanew + 0x4;
    memcpy(&PE,(char*)Offset, sizeof(IMAGE_FILE_HEADER));
    //OPTIONAL
    Offset = (DWORD)hModule + DOS.e_lfanew + 0x18;
    memcpy(&OPTIONAL1, (char*)Offset, sizeof(IMAGE_OPTIONAL_HEADER));
    //SECTIONS
    Offset = (DWORD)hModule + DOS.e_lfanew + 0x18 + PE.SizeOfOptionalHeader;
    memcpy(SECTIONS, (char*)Offset, sizeof(IMAGE_SECTION_HEADER) * PE.NumberOfSections);
    //EXPORT
    Offset = (DWORD)hModule + OPTIONAL1.DataDirectory[0].VirtualAddress;
    memcpy(&ExPort, (char*)Offset, sizeof(IMAGE_EXPORT_DIRECTORY));
    
    DWORD dwAddressOfNames = ExPort.AddressOfNames + (DWORD)hModule;
    int nIndex =-1;
    for (int i = 0; i < ExPort.NumberOfNames; i++)
    {
        DWORD dwpAddressApiName = (DWORD)hModule + (*(DWORD*)(dwAddressOfNames + i * 4));
        if (dwpAddressApiName == NULL)
        {
            continue;
        }
            if (!Mystrcmp((char*)lpProcName, (char*)dwpAddressApiName))
            {
                nIndex = i;
                break;
            }
    }
    //没找到返回NULL
    if (nIndex == -1)
    {
        return NULL;
    }
    DWORD dwAddreessOfNameOrdinals= ExPort.AddressOfNameOrdinals + (DWORD)hModule;
    WORD wOrdinals = (*(WORD*)(dwAddreessOfNameOrdinals + nIndex * 2));
    DWORD dwApiAddress= ExPort.AddressOfFunctions + (DWORD)hModule;
    dwApiAddress = *(DWORD*)(dwApiAddress + (wOrdinals) * 4)+ (DWORD)hModule;
    
    DWORD dwMaxAddress = OPTIONAL1.DataDirectory[0].VirtualAddress + (DWORD)hModule;
    if (dwApiAddress > dwMaxAddress)
    {
        char szDllName[64] = { 0 };
        char szApiName[64] = { 0 };
        char* r = (char*)dwApiAddress;
        int nDllCount = 0;
        while (*r != '.')
        {
            szDllName[nDllCount] = *r;
            r++;
            nDllCount++;
        }
        r++;
        strcpy(szApiName, r);
        dwApiAddress=(DWORD)MyGetProcAddress(GetModuleHandleA(szDllName), szApiName);
        
    }

    return (FARPROC)dwApiAddress;
}

FARPROC MyGetProcAddress(
    HMODULE hModule, // DLL模块句柄
    WORD Ordinals // 序号
)
{
    if (hModule == NULL)
    {
        return 0;
    }
    //DOS
    DWORD Offset = (DWORD)hModule;
    memcpy(&DOS, (char*)Offset, sizeof(IMAGE_DOS_HEADER));
    //PE
    Offset = (DWORD)hModule + DOS.e_lfanew + 0x4;
    memcpy(&PE, (char*)Offset, sizeof(IMAGE_FILE_HEADER));
    //OPTIONAL
    Offset = (DWORD)hModule + DOS.e_lfanew + 0x18;
    memcpy(&OPTIONAL1, (char*)Offset, sizeof(IMAGE_OPTIONAL_HEADER));
    //SECTIONS
    Offset = (DWORD)hModule + DOS.e_lfanew + 0x18 + PE.SizeOfOptionalHeader;
    memcpy(SECTIONS, (char*)Offset, sizeof(IMAGE_SECTION_HEADER) * PE.NumberOfSections);
    //EXPORT
    Offset = (DWORD)hModule + OPTIONAL1.DataDirectory[0].VirtualAddress;
    memcpy(&ExPort, (char*)Offset, sizeof(IMAGE_EXPORT_DIRECTORY));
 

    DWORD dwApiAddress = ExPort.AddressOfFunctions + (DWORD)hModule;
    dwApiAddress = *(DWORD*)(dwApiAddress + (Ordinals- ExPort.Base) * 4) + (DWORD)hModule;

    DWORD dwMaxAddress = OPTIONAL1.DataDirectory[0].VirtualAddress + (DWORD)hModule;
    if (dwApiAddress > dwMaxAddress)
    {
        char szDllName[64] = { 0 };
        char szApiName[64] = { 0 };
        char* r = (char*)dwApiAddress;
        int nDllCount = 0;
        while (*r != '.')
        {
            szDllName[nDllCount] = *r;
            r++;
            nDllCount++;
        }
        r++;
        strcpy(szApiName, r);
        dwApiAddress = (DWORD)MyGetProcAddress(GetModuleHandleA(szDllName), szApiName);

    }
    return (FARPROC)dwApiAddress;

}