0x01 題目

<?php
$output = "";
if (isset($_GET['code'])) {
  $content = file_get_contents("__FILE__");
  $content = preg_replace('/FLAG\-[0-9a-zA-Z_?!.,]+/i', 'FLAG-XXXXXXXXXXXXXXXXXXXXXXX', $content);
  echo '<div class="code-highlight">';
  highlight_string($content);
  echo '</div>';
}
if (isset($_GET['pass'])) {
  if(!preg_match('/^[^\W_]+$/', $_GET['pass'])) {
    $output = "Don't hack me please :(";
  } else {
    $pass = md5("admin1674227342");
    if ((((((((($_GET['pass'] == $pass)))) && (((($pass !== $_GET['pass']))))) || ((((($pass == $_GET['pass'])))) && ((($_GET['pass'] !== $pass)))))))) { // Trolling u lisp masta
      if (strlen($pass) == strlen($_GET['pass'])) {
        $output = "<div class='alert alert-success'>FLAG-XXXXXXXXXXXXXXXXXXXXXXX</div>";
      } else {
        $output = "<div class='alert alert-danger'>Wrong password</div>";
      }
    } else {
      $output = "<div class='alert alert-danger'>Wrong password</div>";
    }
  }
}
echo $output;
?>

0X02 解題

這題主要考察php弱比較。
這里admin1674227342的md5值是0e463854177790028825434984462555，所以只要pass是0e開頭并且長度是32位的即可。