Bug 789638 (CVE-2012-1037)

From full disclosure Emilien Girault reports:

http://permalink.gmane.org/gmane.comp.security.full-disclosure/84497

CVE-2012-1037: GLPI <= 0.80.61 LFI/RFI

Severity: Important

Vendor: GLPI - http://www.glpi-project.org

Versions Affected
=================

All versions between 0.78 and 0.80.61

Description
===========

GLPI fails to properly sanitize the GET 'sub_type' parameter in the front/popup.php file:

  [...]
  checkLoginUser();

  if (isset($_GET["popup"])) {
     $_SESSION["glpipopup"]["name"] = $_GET["popup"];
  }

  if (isset($_SESSION["glpipopup"]["name"])) {
    switch ($_SESSION["glpipopup"]["name"]) {
  [...]
    case "add_ruleparameter" :
           popHeader($LANG['ldap'][35], $_SERVER['PHP_SELF']);
           include strtolower($_GET['sub_type']."Parameter.php");   // <======= 
           break;
  [...]

To be triggered, the attacker needs to be authenticated. However, GLPI provides default accounts that
often aren't changed or disabled:

    glpi/glpi
    tech/tech
    normal/normal
    post-only/postonly

Impact
======

Since there is a suffix, the vulnerability can be used as a RFI (requires allow_url_include = On).

For LFI, the target file has to end up with "parameter.php". GLPI automatically escapes all GET and POST
parameters with addslashes(), so the null byte technique is not usable. I have not tested exploitation
using path truncation technique but it might be possible.

Mitigation
==========

Upgrade to GLPI 0.80.7.

Exploit
=======

http://<server>/front/popup.php?popup=add_ruleparameter&sub_type=<file>

Timeline
========

08 feb 2012 - Found the bug.
09 feb 2012 - Contacted the GLPI Team.
09 feb 2012 - Bug fixed & new version available.

Thanks to the GLPI team for being responsive!

References
==========

http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2012-1037
https://forge.indepnet.net/projects/glpi/versions/685
https://forge.indepnet.net/projects/glpi/repository/revisions/17457/diff/branches/0.80-bugfixes/front/popup.php