smoketests/variableWidthAttack.php

   1 <?php
   2
   3 require_once 'common.php';
   4
   5 ?><!DOCTYPE html
   6      PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN"
   7      "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
   8 <html>
   9 <head>
  10 <title>HTMLPurifier Variable Width Attack Smoketest</title>
  11 <meta http-equiv="Content-Type" content="text/html; charset=UTF-8" />
  12 </head>
  13 <body>
  14 <h1>HTMLPurifier Variable Width Attack Smoketest</h1>
  15 <p>For more information, see
  16 <a href="http://applesoup.googlepages.com/bypass_filter.txt">Cheng Peng Su's
  17 original advisory.</a>  This particular exploit code appears only to work
  18 in Internet Explorer, if it works at all.</p>
  19 <h2>Test</h2>
  20 <?php
  21
  22 $purifier = new HTMLPurifier();
  23
  24 ?>
  25 <table>
  26 <thead><tr><th>ASCII</th><th width="30%">Raw</th><th>Output</th><th>Render</th></tr></thead>
  27 <tbody>
  28 <?php
  29
  30 for ($i = 0; $i < 256; $i++) {
  31     $c = chr($i);
  32     $html = '<img src="" alt="X' . $c . '"';
  33     $html .= '>A"'; // in our out the attribute? ;-)
  34     $html .= "onerror=alert('$i')>O";
  35     $pure_html = $purifier->purify($html);
  36 ?>
  37 <tr>
  38     <td><?php echo $i; ?></td>
  39     <td style="font-size:8pt;"><?php echo escapeHTML($html); ?></td>
  40     <td style="font-size:8pt;"><?php echo escapeHTML($pure_html); ?></td>
  41     <td><?php echo $pure_html; ?></td>
  42 </tr>
  43 <?php } ?>
  44 </tbody>
  45 </table>
  46
  47 <h2>Analysis</h2>
  48
  49 <p>By making sure that UTF-8 is well formed and non-SGML codepoints are
  50 removed, as well as escaping quotes outside of tags, this is a non-threat.</p>
  51
  52 </body>
  53 </html>