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How make IAT Hook in a application using a injected dll

FLASHCODER (11)
Hi,

i'm wanting make IAT Hook in a executable application using a injected dll and already read in several websites from Google about this.

So, i have a code and also think that i have a consistent conclusion based in a reference seen in another forum.

Are they:

1 - Code below makes a IAT Hook only on Import Table of my own dll after loaded on target process.

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

void HookFunction(char* funcName, LPDWORD function);
LPDWORD FoundIAT(char* funcName);

int WINAPI HookMessageBoxA(HWND hWnd, LPCTSTR lpText, LPCTSTR lpCaption, UINT uType);  

BOOL APIENTRY DllMain (HINSTANCE hInstance, DWORD dwReason, LPVOID lpReserved) 
{
    if(dwReason == DLL_PROCESS_ATTACH)
    {
        MessageBox(NULL, "Injeted with success!", "Hello", NULL);
        HookFunction("MessageBoxA", (LPDWORD)&HookMessageBoxA);
    }
    return TRUE;
}

void HookFunction(char* funcName, LPDWORD function)
{
    LPDWORD pOldFunction = FoundIAT(funcName);

    DWORD accessProtectionValue , accessProtec;

    int vProtect = VirtualProtect(pOldFunction, sizeof(LPDWORD), PAGE_EXECUTE_READWRITE, &accessProtectionValue);

    *pOldFunction = (DWORD)function;

    vProtect = VirtualProtect(pOldFunction, sizeof(LPDWORD), accessProtectionValue, &accessProtec);
}

int WINAPI HookMessageBoxA(HWND hWnd, LPCTSTR lpText, LPCTSTR lpCaption, UINT uType)
{
    return MessageBoxA(hWnd, "Hello", "DLL answering here!", uType);
}

LPDWORD FoundIAT(char* funcName)
{
    DWORD test = 0;

    LPVOID pMapping = GetModuleHandle(NULL);

    if (pMapping == NULL)

        exit(-1);

    PIMAGE_DOS_HEADER DosHeader = (PIMAGE_DOS_HEADER) pMapping;

    if (DosHeader->e_magic != IMAGE_DOS_SIGNATURE)

        exit(-1);

    PIMAGE_NT_HEADERS NtHeaders = (PIMAGE_NT_HEADERS) ((char*) DosHeader + DosHeader->e_lfanew);

    if (NtHeaders->Signature != IMAGE_NT_SIGNATURE)

        exit(-1);

    PIMAGE_DATA_DIRECTORY DataDirectory = &NtHeaders->OptionalHeader.DataDirectory[1];

    PIMAGE_IMPORT_DESCRIPTOR ImportDescriptor = (PIMAGE_IMPORT_DESCRIPTOR) ((char*) DosHeader + DataDirectory->VirtualAddress);

    PIMAGE_THUNK_DATA32 OriginalFirstThunk = (PIMAGE_THUNK_DATA32)((char*) DosHeader + ImportDescriptor->OriginalFirstThunk);

    while(OriginalFirstThunk != 0)
    {
        DWORD name = (DWORD)((char*) pMapping + ImportDescriptor->Name);

        OriginalFirstThunk = (PIMAGE_THUNK_DATA32)((char*) DosHeader + ImportDescriptor->OriginalFirstThunk);

        PIMAGE_THUNK_DATA32 FirstThunk = (PIMAGE_THUNK_DATA32)((char*) DosHeader + ImportDescriptor->FirstThunk);

        while(OriginalFirstThunk->u1.AddressOfData != 0)
        {
            PIMAGE_IMPORT_BY_NAME NameImg = (PIMAGE_IMPORT_BY_NAME)((char*) DosHeader + (DWORD)OriginalFirstThunk->u1.AddressOfData);

            test = (DWORD)OriginalFirstThunk->u1.Function & (DWORD)IMAGE_ORDINAL_FLAG32;

            if (test == 0)
            {
                if(strcmp(funcName, (const char*)NameImg->Name) == 0)
                {
                    MessageBox(NULL, NameImg->Name, "", NULL);
                    return (LPDWORD)&(FirstThunk->u1.Function);
                }
            }
            OriginalFirstThunk++;
            FirstThunk++;
        }
        ImportDescriptor++;
    }
    return 0;
}


Source code (http://www.rohitab.com/discuss/topic/37089-c-hookmsgbox/)

2 - And here (http://stackoverflow.com/questions/11592446/how-to-modify-import-address-table-for-run-time-loaded-dll) is a possible solution for this, but i don't know how adapt it for my code above.

This video show exactly how i want make (https://www.youtube.com/watch?v=qKMNLAQE08w).

Any suggestion will welcome (mainly with a piece of code, if possible).
Last edited on
helios (17506)
Why don't you just use a hooking library?
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