第12节 第二种shellcode编写实战(1)

我最近在做一个关于shellcode入门和开发的专题课👩🏻‍💻，主要面向对网络安全技术感兴趣的小伙伴。这是视频版内容对应的文字版材料，内容里面的每一个环境我都亲自测试实操过的记录，有需要的小伙伴可以参考🫡

我的个人主页：https://imbyter.com

一、C语言方式编写shellcode​

1. 新建0.createshellcode.cpp文件：用于生成整个项目的shellcode文件，便于其他项目加载执行shellcode。

#include "a.start.h"
#include "z.end.h"
#include "shellcode.h"#pragma optimize("", off ) 
#pragma comment(linker,"/entry:EntryMain")int EntryMain()
{// 获取shellcode片段大小DWORD dwShellcodeSize = (DWORD)ShellCodeEnd - (DWORD)ShellCodeStart;DWORD   dwWriten = 0;HANDLE  hFile = NULL;// 创建文件，用于保存最后的shellcodehFile = CreateFileA("shellcode.bin", GENERIC_WRITE | GENERIC_READ, FILE_SHARE_READ, NULL, CREATE_ALWAYS, FILE_ATTRIBUTE_NORMAL, 0);if (hFile == INVALID_HANDLE_VALUE){return -1;}// 将shellcode写入到文件if (WriteFile(hFile, ShellCodeStart, dwShellcodeSize, &dwWriten, NULL) == FALSE){CloseHandle(hFile);return -1;}CloseHandle(hFile);return 0;
}

2. 新建a.start.h、z.end.h，以及对应的a.start.cpp、z.end.cpp，分别用于标记shellcode的开始和结束。

a.start.h：

#pragma once// 用于标记shellcode开始
void ShellCodeStart();

a.start.cpp：

#include "a.start.h"
#include "shellcode.h"// 用于标记shellcode开始
void ShellCodeStart()
{// shellcode执行的主要功能ShellcodeMain();
}

z.end.h：

#pragma once// 用于标记shellcode结束
void ShellCodeEnd();

z.end.cpp：

// 次函数仅用来标记shellcode结尾
void ShellCodeEnd()
{}

3. 新建shellcode.h，以及对应的shellcode.cpp，用于编写shellcode执行的主要功能代码。

shellcode.h：

#pragma once#include <windows.h>
#include <Winternl.h>HMODULE GetKernel32BaseAddress();
FARPROC _GetPorcAddress();int ShellcodeMain();// 创建文件
int DoCreateFile();
// 弹框提示
int DoMessageBox();

shellcode.cpp：

#include "shellcode.h"// shellcode主要执行的功能
int ShellcodeMain()
{// 创建文件DoCreateFile();// 弹框提示DoMessageBox();// 其他功能...return 0;
}// 功能：创建文件 D:\1.txt
int DoCreateFile()
{// 获取GetPorcAddress函数地址typedef FARPROC(WINAPI* FN_GetProcAddress)(__in HMODULE hModule, __in LPCSTR lpProcName);FN_GetProcAddress fn_GetProcAddress = (FN_GetProcAddress)_GetPorcAddress();if (fn_GetProcAddress){// 获取LoadLibraryA函数地址char szLoadLibraryA[] = { 'L','o','a','d','L','i','b','r','a','r','y','A',0 };typedef HMODULE(WINAPI* FN_LoadLibraryA)(__in LPCSTR lpLibFileName);FN_LoadLibraryA fn_LoadLibraryA = (FN_LoadLibraryA)fn_GetProcAddress(GetKernel32BaseAddress(), szLoadLibraryA);if (fn_LoadLibraryA){// 获取CreateFileA函数地址char szCreateFileA[] = { 'C','r','e','a','t','e','F','i','l','e','A',0 };typedef HANDLE(WINAPI* FN_CreateFileA)(_In_ LPCSTR lpFileName,_In_ DWORD dwDesiredAccess,_In_ DWORD dwShareMode,_In_opt_ LPSECURITY_ATTRIBUTES lpSecurityAttributes,_In_ DWORD dwCreationDisposition,_In_ DWORD dwFlagsAndAttributes,_In_opt_ HANDLE hTemplateFile);FN_CreateFileA fn_CreateFileA = (FN_CreateFileA)fn_GetProcAddress(GetKernel32BaseAddress(), szCreateFileA);// 执行CreateFileAchar szFilePath[] = { 'D',':','\\','1','.','t','x','t',0 };fn_CreateFileA(szFilePath, GENERIC_WRITE, 0, NULL, CREATE_ALWAYS, 0, NULL);}}return 0;
}// 功能：弹框提示
int DoMessageBox()
{// 获取GetPorcAddress函数地址typedef FARPROC(WINAPI* FN_GetProcAddress)(__in HMODULE hModule, __in LPCSTR lpProcName);FN_GetProcAddress fn_GetProcAddress = (FN_GetProcAddress)_GetPorcAddress();if (fn_GetProcAddress){// 获取LoadLibraryA函数地址char szLoadLibraryA[] = { 'L','o','a','d','L','i','b','r','a','r','y','A',0 };typedef HMODULE(WINAPI* FN_LoadLibraryA)(__in LPCSTR lpLibFileName);FN_LoadLibraryA fn_LoadLibraryA = (FN_LoadLibraryA)fn_GetProcAddress(GetKernel32BaseAddress(), szLoadLibraryA);if (fn_LoadLibraryA){// 获取MessageBoxA函数地址char szUser32[] = { 'U','s','e','r','3','2','.','d','l','l',0 };char szMessageBoxA[] = { 'M','e','s','s','a','g','e','B','o','x','A',0 };typedef int (WINAPI* FN_MessageBoxA)(__in_opt HWND hWnd, __in_opt LPCSTR lpText, __in_opt LPCSTR lpCaption, __in UINT uType);FN_MessageBoxA fn_MessageBoxA = (FN_MessageBoxA)fn_GetProcAddress(fn_LoadLibraryA(szUser32), szMessageBoxA);// 执行MessageBoxAchar szCaption[] = { 't','i','t','l','e',0 };char szText[] = { 'H','e','l','l','o',' ','W','o','r','l','d', 0 };fn_MessageBoxA(0, szText, szCaption, MB_OK | MB_ICONINFORMATION);}}return 0;
}// 获取kernel32基址
HMODULE GetKernel32BaseAddress()
{HMODULE hKernel32 = NULL;// 用户保存模块名WCHAR wszModuleName[MAX_PATH];#ifdef _WIN64    // 64位PEB偏移为0x60PPEB lpPeb = (PPEB)__readgsqword(0x60);
#else            // 32位PEB偏移为0x30PPEB lpPeb = (PPEB)__readfsdword(0x30);
#endifPLIST_ENTRY pListHead = &lpPeb->Ldr->InMemoryOrderModuleList;PLIST_ENTRY pListData = pListHead->Flink;// 遍历所有模块while (pListData != pListHead){PLDR_DATA_TABLE_ENTRY pLDRData = CONTAINING_RECORD(pListData, LDR_DATA_TABLE_ENTRY, InMemoryOrderLinks);DWORD dwLen = pLDRData->FullDllName.Length / 2;if (dwLen > 12)    // 12 是"kernel32.dll"的长度，获取到的完整路径肯定要比模块名长{// 从获取到的模块完整路径中提取模块名for (size_t i = 0; i < 12; i++){wszModuleName[11 - i] = pLDRData->FullDllName.Buffer[dwLen - 1 - i];}// 最终要获取的目标模块名（"kernel32.dll"），逐个字节比较，包含大小写。if ((wszModuleName[0] == 'k' || wszModuleName[0] == 'K') &&(wszModuleName[1] == 'e' || wszModuleName[1] == 'E') &&(wszModuleName[2] == 'r' || wszModuleName[2] == 'R') &&(wszModuleName[3] == 'n' || wszModuleName[3] == 'N') &&(wszModuleName[4] == 'e' || wszModuleName[4] == 'E') &&(wszModuleName[5] == 'l' || wszModuleName[5] == 'L') &&(wszModuleName[6] == '3') &&(wszModuleName[7] == '2') &&(wszModuleName[8] == '.') &&(wszModuleName[9] == 'd' || wszModuleName[9] == 'D') &&(wszModuleName[10] == 'l' || wszModuleName[10] == 'L') &&(wszModuleName[11] == 'l' || wszModuleName[11] == 'L')){hKernel32 = (HMODULE)pLDRData->DllBase;break;}}pListData = pListData->Flink;}return hKernel32;
}// 获取GetPorcAddress函数地址
FARPROC _GetPorcAddress()
{// 保存最终结果FARPROC pGetPorcAddress = NULL;// kernel32基址HMODULE hKernel32 = GetKernel32BaseAddress();if (!hKernel32){return NULL;}PIMAGE_DOS_HEADER lpDosHeader = (PIMAGE_DOS_HEADER)hKernel32;PIMAGE_NT_HEADERS lpNTHeader = (PIMAGE_NT_HEADERS)((unsigned char*)hKernel32 + lpDosHeader->e_lfanew);// 模块有效性验证if (!lpNTHeader->OptionalHeader.DataDirectory[IMAGE_DIRECTORY_ENTRY_EXPORT].Size){return NULL;}if (!lpNTHeader->OptionalHeader.DataDirectory[IMAGE_DIRECTORY_ENTRY_EXPORT].VirtualAddress){return NULL;}// 通过导出表中的导出函数名，定位"GetProcAddress"的位置PIMAGE_EXPORT_DIRECTORY lpExports = (PIMAGE_EXPORT_DIRECTORY)((unsigned char*)hKernel32 + lpNTHeader->OptionalHeader.DataDirectory[IMAGE_DIRECTORY_ENTRY_EXPORT].VirtualAddress);PDWORD lpdwFunName = (PDWORD)((unsigned char*)hKernel32 + lpExports->AddressOfNames);PWORD lpdwOrd = (PWORD)((unsigned char*)hKernel32 + lpExports->AddressOfNameOrdinals);PDWORD lpdwFunAddr = (PDWORD)((unsigned char*)hKernel32 + lpExports->AddressOfFunctions);for (DWORD dwLoop = 0; dwLoop <= lpExports->NumberOfNames - 1; dwLoop++){char* pFunName = (char*)(lpdwFunName[dwLoop] + (unsigned char*)hKernel32);// 比较函数名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'){pGetPorcAddress = (FARPROC)(lpdwFunAddr[lpdwOrd[dwLoop]] + (unsigned char*)hKernel32);break;}}return pGetPorcAddress;
}

最后的框架结构如下图：

后续开发所有功能都可以在遵循shellcode编写原则的基础上，以新的.h头文件.cpp源文件进行扩展。

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二、C++类方式编写shellcode​

也可以使用C++类的方式进行编写，比如将shellcode.cpp改为CDoShellcode类的方式实现：

shellcode.h：

#pragma once#include <windows.h>
#include <Winternl.h>class CDoShellcode
{
private:HMODULE GetKernel32BaseAddress();FARPROC _GetPorcAddress();public:// 创建文件int DoCreateFile();// 弹框提示int DoMessageBox();
};

shellcode.cpp：

#include "shellcode.h"// 功能：创建文件 D:\1.txt
int CDoShellcode::DoCreateFile()
{// 获取GetPorcAddress函数地址typedef FARPROC(WINAPI* FN_GetProcAddress)(__in HMODULE hModule, __in LPCSTR lpProcName);FN_GetProcAddress fn_GetProcAddress = (FN_GetProcAddress)_GetPorcAddress();if (fn_GetProcAddress){// 获取LoadLibraryA函数地址char szLoadLibraryA[] = { 'L','o','a','d','L','i','b','r','a','r','y','A',0 };typedef HMODULE(WINAPI* FN_LoadLibraryA)(__in LPCSTR lpLibFileName);FN_LoadLibraryA fn_LoadLibraryA = (FN_LoadLibraryA)fn_GetProcAddress(GetKernel32BaseAddress(), szLoadLibraryA);if (fn_LoadLibraryA){// 获取CreateFileA函数地址char szCreateFileA[] = { 'C','r','e','a','t','e','F','i','l','e','A',0 };typedef HANDLE(WINAPI* FN_CreateFileA)(_In_ LPCSTR lpFileName,_In_ DWORD dwDesiredAccess,_In_ DWORD dwShareMode,_In_opt_ LPSECURITY_ATTRIBUTES lpSecurityAttributes,_In_ DWORD dwCreationDisposition,_In_ DWORD dwFlagsAndAttributes,_In_opt_ HANDLE hTemplateFile);FN_CreateFileA fn_CreateFileA = (FN_CreateFileA)fn_GetProcAddress(GetKernel32BaseAddress(), szCreateFileA);// 执行CreateFileAchar szFilePath[] = { 'D',':','\\','1','.','t','x','t',0 };fn_CreateFileA(szFilePath, GENERIC_WRITE, 0, NULL, CREATE_ALWAYS, 0, NULL);}}return 0;
}// 功能：弹框提示
int CDoShellcode::DoMessageBox()
{// 获取GetPorcAddress函数地址typedef FARPROC(WINAPI* FN_GetProcAddress)(__in HMODULE hModule, __in LPCSTR lpProcName);FN_GetProcAddress fn_GetProcAddress = (FN_GetProcAddress)_GetPorcAddress();if (fn_GetProcAddress){// 获取LoadLibraryA函数地址char szLoadLibraryA[] = { 'L','o','a','d','L','i','b','r','a','r','y','A',0 };typedef HMODULE(WINAPI* FN_LoadLibraryA)(__in LPCSTR lpLibFileName);FN_LoadLibraryA fn_LoadLibraryA = (FN_LoadLibraryA)fn_GetProcAddress(GetKernel32BaseAddress(), szLoadLibraryA);if (fn_LoadLibraryA){// 获取MessageBoxA函数地址char szUser32[] = { 'U','s','e','r','3','2','.','d','l','l',0 };char szMessageBoxA[] = { 'M','e','s','s','a','g','e','B','o','x','A',0 };typedef int (WINAPI* FN_MessageBoxA)(__in_opt HWND hWnd, __in_opt LPCSTR lpText, __in_opt LPCSTR lpCaption, __in UINT uType);FN_MessageBoxA fn_MessageBoxA = (FN_MessageBoxA)fn_GetProcAddress(fn_LoadLibraryA(szUser32), szMessageBoxA);// 执行MessageBoxAchar szCaption[] = { 't','i','t','l','e',0 };char szText[] = { 'H','e','l','l','o',' ','W','o','r','l','d', 0 };fn_MessageBoxA(0, szText, szCaption, MB_OK | MB_ICONINFORMATION);}}return 0;
}// 获取kernel32基址
HMODULE CDoShellcode::GetKernel32BaseAddress()
{HMODULE hKernel32 = NULL;// 用户保存模块名WCHAR wszModuleName[MAX_PATH];#ifdef _WIN64    // 64位PEB偏移为0x60PPEB lpPeb = (PPEB)__readgsqword(0x60);
#else            // 32位PEB偏移为0x30PPEB lpPeb = (PPEB)__readfsdword(0x30);
#endifPLIST_ENTRY pListHead = &lpPeb->Ldr->InMemoryOrderModuleList;PLIST_ENTRY pListData = pListHead->Flink;// 遍历所有模块while (pListData != pListHead){PLDR_DATA_TABLE_ENTRY pLDRData = CONTAINING_RECORD(pListData, LDR_DATA_TABLE_ENTRY, InMemoryOrderLinks);DWORD dwLen = pLDRData->FullDllName.Length / 2;if (dwLen > 12)    // 12 是"kernel32.dll"的长度，获取到的完整路径肯定要比模块名长{// 从获取到的模块完整路径中提取模块名for (size_t i = 0; i < 12; i++){wszModuleName[11 - i] = pLDRData->FullDllName.Buffer[dwLen - 1 - i];}// 最终要获取的目标模块名（"kernel32.dll"），逐个字节比较，包含大小写。if ((wszModuleName[0] == 'k' || wszModuleName[0] == 'K') &&(wszModuleName[1] == 'e' || wszModuleName[1] == 'E') &&(wszModuleName[2] == 'r' || wszModuleName[2] == 'R') &&(wszModuleName[3] == 'n' || wszModuleName[3] == 'N') &&(wszModuleName[4] == 'e' || wszModuleName[4] == 'E') &&(wszModuleName[5] == 'l' || wszModuleName[5] == 'L') &&(wszModuleName[6] == '3') &&(wszModuleName[7] == '2') &&(wszModuleName[8] == '.') &&(wszModuleName[9] == 'd' || wszModuleName[9] == 'D') &&(wszModuleName[10] == 'l' || wszModuleName[10] == 'L') &&(wszModuleName[11] == 'l' || wszModuleName[11] == 'L')){hKernel32 = (HMODULE)pLDRData->DllBase;break;}}pListData = pListData->Flink;}return hKernel32;
}// 获取GetPorcAddress函数地址
FARPROC CDoShellcode::_GetPorcAddress()
{// 保存最终结果FARPROC pGetPorcAddress = NULL;// kernel32基址HMODULE hKernel32 = GetKernel32BaseAddress();if (!hKernel32){return NULL;}PIMAGE_DOS_HEADER lpDosHeader = (PIMAGE_DOS_HEADER)hKernel32;PIMAGE_NT_HEADERS lpNTHeader = (PIMAGE_NT_HEADERS)((unsigned char*)hKernel32 + lpDosHeader->e_lfanew);// 模块有效性验证if (!lpNTHeader->OptionalHeader.DataDirectory[IMAGE_DIRECTORY_ENTRY_EXPORT].Size){return NULL;}if (!lpNTHeader->OptionalHeader.DataDirectory[IMAGE_DIRECTORY_ENTRY_EXPORT].VirtualAddress){return NULL;}// 通过导出表中的导出函数名，定位"GetProcAddress"的位置PIMAGE_EXPORT_DIRECTORY lpExports = (PIMAGE_EXPORT_DIRECTORY)((unsigned char*)hKernel32 + lpNTHeader->OptionalHeader.DataDirectory[IMAGE_DIRECTORY_ENTRY_EXPORT].VirtualAddress);PDWORD lpdwFunName = (PDWORD)((unsigned char*)hKernel32 + lpExports->AddressOfNames);PWORD lpdwOrd = (PWORD)((unsigned char*)hKernel32 + lpExports->AddressOfNameOrdinals);PDWORD lpdwFunAddr = (PDWORD)((unsigned char*)hKernel32 + lpExports->AddressOfFunctions);for (DWORD dwLoop = 0; dwLoop <= lpExports->NumberOfNames - 1; dwLoop++){char* pFunName = (char*)(lpdwFunName[dwLoop] + (unsigned char*)hKernel32);// 比较函数名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'){pGetPorcAddress = (FARPROC)(lpdwFunAddr[lpdwOrd[dwLoop]] + (unsigned char*)hKernel32);break;}}return pGetPorcAddress;
}

然后将a.start.cpp中的ShellCodeStart函数改为：

void ShellCodeStart()
{CDoShellcode shellcode;// 创建文件shellcode.DoCreateFile();// 弹框提示shellcode.DoMessageBox();// 其他功能...
}

这样即可实现类的方式执行shellcode功能。

测试：运行以上代码对应生成的exe文件，会在当前路径下生成shellcode.bin文件，该文件就是我们最后得到的shellcode文件。使用编写shellcode加载器加载执行shellcode.bin测试效果。

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