Drupal Sections Module XSS Vulnerability

[Justin Klein Keane <justin () madirish net>]

The text of this announcment is also available at
http://www.madirish.net/?article=440

Description of Vulnerability:
- - -----------------------------
Drupal (http://drupal.org) is a robust content management system (CMS)
written in PHP and MySQL that provides extensibility through various third
party modules.  The Sections module (http://drupal.org/project/sections)
"allows you to create sections within your site. Each section has an
installed template, theme or style attached to it."

The Sections module contains a cross site scripting vulnerability because it
does not properly sanitize output of section names before display.

Systems affected:
- - -----------------
Drupal 6.14 with Sections 6.x-1.2 was tested and shown to be vulnerable.

Impact:
- - -------
XSS vulnerabilities may expose site administrative accounts to compromise
which could lead to web server process compromise.

Mitigating factors:
- - -------------------
The Sections module must be installed.  To carry out a Sections based XSS
proof of concept exploit below the attacker must have 'administer sections'
permissions.

Proof of Concept:
- ---------------------
1.  Install Drupal 6.14
2.  Install Sections 6.x-1.2
3.  Enable the Sections module from Administer -> Site building -> Modules
4.  Click Administer -> Site building -> Sections
5.  Click the 'Add section' button
5.  Enter "<script>alert('xss');</script>" in the 'Name' text area
6.  Click the 'Add section' button to save the section and observe the
rendered JavaScript
7.  Click on the 'Sections' link in the navigation to observe the rendered
JavaScript

Technical details:
- ------------------------
The Sections module fails to sanitize the output of the section name before
display.  Applying the following patch fixes this vulnerability.

Patch
- -------
Applying the following patch mitigates these threats.

--- sections/sections.admin.inc 2008-06-01 08:51:51.000000000 -0400
+++ sections.fixed/sections.admin.inc   2009-11-06 15:43:53.997416137 -0500
@@ -234,6 +234,7 @@ function theme_sections_admin_display_fo
   foreach (element_children($form['sections']) as $key => $id) {
     // Don't take form control structures.
     if (is_array($form['sections'][$id]['name'])) {
+      $form['sections'][$id]['name']['#value'] =
filter_xss($form['sections'][$id]['name']['#value']);
       $form['sections'][$id]['weight']['#attributes']['class'] =
'sections-order-weight';
       $rows[] = array(
         'data' => array(


Vendor Response
---------------
Upgrade to the latest version.
SA-CONTRIB-2009-112 http://drupal.org/node/661404

-- 
Justin C. Klein Keane
http://www.MadIrish.net

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