PE学习：导入表注入

最近深感自己基础不牢，回头学了一遍PE，顺手做了个导入表注入的小练习

首先准备一个DLL用来测试

BOOL APIENTRY DllMain( HMODULE hModule,
                       DWORD  ul_reason_for_call,
                       LPVOID lpReserved
                     )
{
    switch (ul_reason_for_call)
    {
    case DLL_PROCESS_ATTACH:
        init();
    case DLL_THREAD_ATTACH:
    case DLL_THREAD_DETACH:
    case DLL_PROCESS_DETACH:
        break;
    }
    return TRUE;
}

void init() {
    MessageBoxA(0, "Success", "Test", MB_OK);
}

int plus(int a, int b) {
    return a + b;
}

再准备一个exe

.386
.MODEL flat,stdcall
option casemap:none

include        windows.inc
include        gdi32.inc
includelib    gdi32.lib
include        user32.inc
includelib    user32.lib
include        kernel32.inc
includelib    kernel32.lib

.data?
hInstance    dd    ?
hWinMain    dd    ?

.const        
szClassName        db    'Myclass',0
szCaptionMain    db    'My first window',0
szText            db  'win32 Assembly,simple and powerful !',0
szButton        db    'button',0
szButtonText    db    '&ok',0

.code

_ProcWinMain    proc    uses ebx edi esi,hWnd,uMsg,wParam,lParam
    local    @stPs:PAINTSTRUCT
    local    @stRect:RECT
    local    @hDc

    mov        eax,uMsg
    .if        eax == WM_PAINT
            invoke    BeginPaint,hWnd,addr @stPs
            mov        @hDc,eax
            invoke    GetClientRect,hWnd,addr @stRect
            invoke    DrawText,@hDc,addr szText,-1,addr @stRect,DT_SINGLELINE or DT_CENTER or DT_VCENTER
            invoke    EndPaint,hWnd,addr @stPs

    .elseif    eax == WM_CLOSE
            invoke    DestroyWindow,hWinMain
            invoke    PostQuitMessage,NULL

    .else
            invoke    DefWindowProc,hWnd,uMsg,wParam,lParam
            ret

    .endif
    xor        eax,eax
    ret

_ProcWinMain    endp

_WinMain    proc
    local    @stWndClass:WNDCLASSEX
    local    @stMsg:MSG

    invoke    GetModuleHandle,NULL
    mov        hInstance,eax
    invoke    RtlZeroMemory,addr @stWndClass,sizeof @stWndClass

    invoke    LoadCursor,0,IDC_ARROW
    mov        @stWndClass.hCursor,eax
    push    hInstance
    pop        @stWndClass.hInstance
    mov        @stWndClass.cbSize,sizeof WNDCLASSEX
    mov        @stWndClass.style,CS_HREDRAW or CS_VREDRAW
    mov        @stWndClass.lpfnWndProc,offset _ProcWinMain
    mov        @stWndClass.hbrBackground,COLOR_WINDOW + 1
    mov        @stWndClass.lpszClassName,offset szClassName
    invoke    RegisterClassEx,addr @stWndClass

    invoke    CreateWindowEx,WS_EX_CLIENTEDGE,offset szClassName,offset szCaptionMain,
            WS_OVERLAPPEDWINDOW,100,100,600,400,NULL,NULL,hInstance,NULL
    mov        hWinMain,eax
    invoke    ShowWindow,hWinMain,SW_SHOWNORMAL
    invoke    UpdateWindow,hWinMain

    .while    TRUE
        invoke    GetMessage,addr @stMsg,NULL,0,0
        .break    .if    eax == 0
        invoke    TranslateMessage,addr @stMsg
        invoke    DispatchMessage,addr @stMsg
    .endw
    ret

_WinMain    endp

start:
    call    _WinMain
    invoke    ExitProcess,NULL

end    start

运行效果

要完成导入表注入，需要以下几步

1    打开一个exe
2    新增一个节
3    把导入表移进去
4    写入自己的导入表
5    存盘

关于导入表的资料网上有很多我就不细说了，这里主要就放一下代码，这个代码我写的很随意，看着应该比较丑hhhhh

>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>

FILE* fp = fopen(fileName, "rb");
    if (fp == NULL) {
        printf("open failed
");
        exit(0);
    }
    fseek(fp, 0, SEEK_END);
    unsigned int len = ftell(fp);
    fseek(fp, 0, SEEK_SET);
    char* buf = (char*)malloc(2 * len);//因为exe要扩充，所以这里直接扩了一倍，简单暴力hhh
    if (buf != NULL) {
        memset(buf, 'x00', 2 * len);
        fread(buf, len, 1, fp);
    }
    fclose(fp);
    char* lpnewSec = buf + newSection(buf);//指向新增的节
    inject(buf, lpnewSec, fileName);
    free(buf);
    buf = NULL;

新增节：

unsigned __int32 newSection(char* buf) {
    unsigned __int32 e_lfanew = *(unsigned __int32*)(buf + 0x3c);
    char* FIheader = buf + e_lfanew + 4;
    char* OPheader = FIheader+0x14;
//扩大地址，我直接加了一个内存对齐的大小
    unsigned __int32 SectionAlignment = *(unsigned __int32*)(OPheader + 0x20);
    unsigned __int32 SizeOfImage = *(unsigned __int32*)(OPheader + 0x38);
    *(unsigned __int32*)(buf + 0x38 + (e_lfanew + 0x18)) = SizeOfImage + SectionAlignment;
    SizeOfImage = *(unsigned __int32*)(OPheader + 0x38);
    unsigned __int32 SizeoOfHeaders = *(unsigned __int32*)(OPheader + 0x3c);
    unsigned __int16 NumberOfSections = *(unsigned __int16*)(FIheader + 0x2);
    __int16 SizeOfOptionalHeader = *(unsigned __int16*)(FIheader + 0x10);
    char* Sections_addr = OPheader + SizeOfOptionalHeader;

//遍历节表
    unsigned __int32 Misc = 0;
    unsigned __int32 VirtualAddress = 0;
    unsigned __int32 SizeOfRawData = 0;
    unsigned __int32 PointerToRawData = 0;
    unsigned __int32 Characteristics = 0;
    for (int j = 0; j < NumberOfSections; j++) {
        Misc = *(unsigned __int32*)(Sections_addr + 0x8);
        VirtualAddress = *(unsigned __int32*)(Sections_addr + 0xc);
        SizeOfRawData = *(unsigned __int32*)(Sections_addr + 0x10);
        PointerToRawData = *(unsigned __int32*)(Sections_addr + 0x14);
        Characteristics |= *(unsigned __int32*)(Sections_addr + 0x24);
        Sections_addr = Sections_addr + 0x28;
    }
    unsigned int check = SizeoOfHeaders - (Sections_addr - buf);
//当节表与第一个节的距离小于0x50时不能加节表，可以通过合并节等方式处理，这里没管   
　　 if (check < 0x50) {
        printf("can't add new Section");
        exit(0);
    }
    *(unsigned __int16*)(FIheader + 0x2) += 1;//节表长度加一
//加入新节表
    unsigned __int32 newSec_addr = VirtualAddress + SectionAlignment;
    unsigned __int32 newSec_PointerToRawData = PointerToRawData + SizeOfRawData;
    *(unsigned __int64*)Sections_addr = 0x000000006362612e;//节名我直接取abc了
    *(unsigned __int32*)(Sections_addr + 0x8) = SectionAlignment;
    *(unsigned __int32*)(Sections_addr + 0xc) = newSec_addr;
    *(unsigned __int32*)(Sections_addr + 0x10) = SectionAlignment;
    *(unsigned __int32*)(Sections_addr + 0x14) = newSec_PointerToRawData;
    *(unsigned __int32*)(Sections_addr + 0x24) = Characteristics;
    return newSec_PointerToRawData;
}

注入

void inject(char* buf, char* newSec,const char* fileName) {
    unsigned __int32 e_lfanew = *(unsigned __int32*)(buf + 0x3c);
    char* FIheader = buf + e_lfanew + 4;
    char* OPheader = FIheader + 0x14;
    unsigned __int16 NumberOfSections = *(unsigned __int16*)(FIheader + 0x2);
    __int16 SizeOfOptionalHeader = *(unsigned __int16*)(FIheader + 0x10);

    char* Sections_addr = OPheader + SizeOfOptionalHeader;
    unsigned __int32 VirtualAddress = 0;
    unsigned __int32 SizeOfRawData = 0;
    unsigned __int32 PointerToRawData = 0;
    for (int j = 0; j < NumberOfSections; j++) {
        VirtualAddress = *(unsigned __int32*)(Sections_addr + 0xc);
        SizeOfRawData = *(unsigned __int32*)(Sections_addr + 0x10);
        PointerToRawData = *(unsigned __int32*)(Sections_addr + 0x14);
        Sections_addr = Sections_addr + 0x28;
    }

    char* lpDirectory = OPheader + SizeOfOptionalHeader - 0x80;
    unsigned __int32 ImportRVA = *(unsigned __int32*)(lpDirectory + 0x8);
    *(unsigned __int32*)(lpDirectory + 0x8) = VirtualAddress;
    unsigned __int32 ImportFOA = RVA_to_FOA(buf, ImportRVA);
    char* importAddr = buf + ImportFOA;
    char* newImport = newSec;
    unsigned __int32 count = 0;
//移动导入表，没有动INT和IAT
    while (*(unsigned __int32*)importAddr || *(unsigned __int32*)(importAddr + 0x4) || *(unsigned __int32*)(importAddr + 0x8) || *(unsigned __int32*)(importAddr + 0xc) || *(unsigned __int32*)(importAddr + 0x4)) {
        for (unsigned __int32 i = 0; i < 0x14; i++) {
            *(newImport + i) = *(importAddr + i);
        }
        count += 0x14;
        newImport += 0x14;
        importAddr += 0x14;
    }
    //new import
    *(unsigned __int32*)(newImport + 0x0) = VirtualAddress + count + 0x14;//指向新的INT
    *(unsigned __int32*)(newImport + 0x4) = 0;
    *(unsigned __int32*)(newImport + 0x8) = 0;
    *(unsigned __int32*)(newImport + 0xc) = VirtualAddress + count + 0x2b;//指向注入的DLL名
    *(unsigned __int32*)(newImport + 0x10) = VirtualAddress + count + 0x1c;//指向IAT
    //INT
    *(unsigned __int32*)(newImport + 0x14) = VirtualAddress + count + 0x24;//指向导入函数名，下面IAT也指向此处
    *(unsigned __int32*)(newImport + 0x18) = 0;
    //IAT
    *(unsigned __int32*)(newImport + 0x1c) = VirtualAddress + count + 0x24;
    *(unsigned __int32*)(newImport + 0x20) = 0;
//这里必须要有导入的函数，否则不会加载dll
    *(unsigned __int16*)(newImport + 0x24) = 0;
    *(unsigned __int32*)(newImport + 0x26) = 0x73756c70;//plus
    *(newImport + 0x2a) = (char)0;
//dLL name：testDLL.dll
    *(unsigned __int32*)(newImport + 0x2b) = 0x74736574;
    *(unsigned __int32*)(newImport + 0x2f) = 0x2e6c6c44;
    *(unsigned __int32*)(newImport + 0x33) = 0x006c6c64;

    FILE* fp = fopen(fileName, "wb");
    if (fp == NULL) {
        printf("open failed
");
        exit(0);
    }
    fwrite(buf, SizeOfRawData + PointerToRawData, 1, fp);
    fclose(fp);
}

RVA转为FOA

unsigned __int32 RVA_to_FOA(char* buf, unsigned __int32 RVA) {
    unsigned __int32 e_lfanew = *(unsigned __int32*)(buf + 0x3c);
    unsigned __int32 SizeoOfHeaders = *(unsigned __int32*)(buf + 0x3c + (e_lfanew + 0x18));
    unsigned __int32 FOA = 0;
//在文件头中不拉伸
    if (RVA <= SizeoOfHeaders) {
        FOA = RVA;
        return FOA;
    }
    unsigned __int16 NumberOfSections = *(unsigned __int16*)(buf + e_lfanew + 0x4 + 0x2);
    __int16 SizeOfOptionalHeader = *(unsigned __int16*)(buf + e_lfanew + 0x4 + 0x10);
    char* Sections_addr = buf + e_lfanew + 0x18 + SizeOfOptionalHeader;
//遍历节表判断在那个节中，FOA=RVA-节的RVA+节的FOA
    unsigned __int32 VirtualAddress = *(unsigned __int32*)(Sections_addr + 0xc);
    unsigned __int32 PointerToRawData = *(unsigned __int32*)(Sections_addr + 0x14);
    unsigned __int32 PrevVirtualAddress = *(unsigned __int32*)(Sections_addr + 0xc);
    unsigned __int32 PrevPointerToRawData = *(unsigned __int32*)(Sections_addr + 0x14);
    Sections_addr = Sections_addr + 0x28;
    for (int j = 0; j < NumberOfSections - 1; j++) {
        VirtualAddress = *(unsigned __int32*)(Sections_addr + 0xc);
        PointerToRawData = *(unsigned __int32*)(Sections_addr + 0x14);
        if (PrevVirtualAddress <= RVA && VirtualAddress > RVA) {
            FOA = PrevPointerToRawData + (RVA - PrevVirtualAddress);
            return FOA;
        }
        PrevVirtualAddress = VirtualAddress;
        PrevPointerToRawData = PointerToRawData;
        Sections_addr = Sections_addr + 0x28;
    }
    FOA = PrevPointerToRawData + (RVA - PrevVirtualAddress);
    return FOA;
}

>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>

注入后

运行