.NET loader string decryption + extraction of encrypted payload in loader resources

loader.ps1

#Sample => https://bazaar.abuse.ch/sample/3c37d7351c091a9c2fce72ecde4bcd1265f148dc3b77017d468e08741091bc50/
$reflectedAsm = [System.Reflection.Assembly]::LoadFile("C:\dotNetLoader.bin")

$mainType = $reflectedAsm.GetType("rwcQssqTcyOdXXoBLoie.DCPmslvtGCDAiOhxxQvq")

$key = [System.Convert]::FromBase64String("iUlREPUR7NQ6ocefGLoxBty1eSNembQTSWsROZidb0A=")
$iv = [System.Convert]::FromBase64String("U+YnktYGyx/j43tP2+WVyw==")

$encryptedStrings = ("8qhzRqWw9fiH/7/a5reZMA==", "D/l1SD7OECP0XB2rUm87gA==", "lbk35FoNbOitTifMeNV97Q==", "uJDwrcc4OjLfnn4YCE0Bxw==", "x9nd50/ydQ4NyJMlduaTA1aZE7EpXLNuSa2GwfmjWlxjNEtyTrE+c9z9hlGIXS4Q")

foreach ($encArg in $encryptedStrings){
    $decodedArg = [System.Convert]::FromBase64String($encArg)
    $DecResult = [System.Text.Encoding]::UTF8.GetString(($mainType.GetMethod("MvljRQYEXFVoIflOHPxg")).invoke($null,@($decodedArg, $key, $iv)))
    Write-Output $DecResult
}

$stream = $reflectedAsm.GetManifestResourceStream("payload.exe")
$binaryReader = New-Object System.IO.BinaryReader($stream)
$contents = $binaryReader.ReadBytes($stream.Length)
$DecResult = $mainType.GetMethod("MvljRQYEXFVoIflOHPxg").invoke($null,@($contents, $key, $iv))
$binaryDecom = $mainType.GetMethod("XWmzUoViPReUSRriqGvB").invoke($null, @(,$DecResult))

[io.file]::WriteAllBytes('C:\one_decom.bin',$binaryDecom)