Security Advisory - Curesec Research Team

1. Introduction

Affected Product:    pfsense 2.3.2
Fixed in:            2.3.3
Fixed Version Link:  https://pfsense.org/download/
Vendor Website:      https://www.pfsense.org/
Vulnerability Type:  XSS
Remote Exploitable:  Yes
Reported to vendor:  02/06/2017
Disclosed to public: 03/24/2017
Release mode:        Coordinated Release
CVE:                 requested via DWF
Credits              Tim Coen of Curesec GmbH

2. Overview

pfsense is an open source firewall. The web interface is written in PHP. In
version 2.3.2-RELEASE (amd64), it is vulnerable to reflected XSS. XSS can lead
to disclosure of cookies, session tokens etc.

3. Details

XSS 1

CVSS: Medium; 6.1 https://www.first.org/cvss/calculator/3.0#CVSS:3.0/AV:N/AC:L/
PR:N/UI:R/S:C/C:L/I:L/A:N

Description: When performing a package reinstall via the package manager, the
"from" and "to" parameter are vulnerable to reflected XSS.

Proof of Concept:

http://192.168.178.60/pkg_mgr_install.php?mode=reinstallpkg&pkg=
pfSense-pkg-arping&from='"><img src=no onerror=alert(1)>&to='"><img src=no
onerror=alert(1)>

Note that while the "pkg" parameter must be a valid package, it does not need
to actually be installed on the system.

Code:

pkg_mgr_install.php <?=sprintf(gettext('Confirmation Required to upgrade
package %1$s from %2$s to %3$s.'), $pkgname, $_GET['from'], $_GET['to'])?>

XSS 2

CVSS: Medium; 4.7 https://www.first.org/cvss/calculator/3.0#CVSS:3.0/AV:N/AC:H/
PR:N/UI:R/S:C/C:L/I:L/A:N

Description: The pkg_filter Parameter of the pkg.php file is vulnerable to
reflected XSS. It should be noted that the xml Parameter must point to an
existing xml file, which must contain a field with the type sorting and the
include_filtering_inputbox tag set. According to the vendor, the FreeRADIUS
package is affected.

Proof of Concept:

192.168.10.150/pkg.php?xml=miniupnpd.xml&pkg_filter='"><img src=no onerror=
alert(1)>

Code:

pkg.php echo "  Filter text: <input id='pkg_filter' name='pkg_filter' value='"
. $_REQUEST['pkg_filter'] . "' /> <input type='submit' value='Filter' />";

4. Solution

To mitigate this issue please upgrade at least to version 2.3.3:

https://pfsense.org/download/

Please note that a newer version might already be available.

5. Report Timeline

02/06/2017 Informed Vendor about Issue
02/07/2017 Vendor confirms + fixes issues in git
02/20/2017 Vendor relases fix + vendor advisory
03/24/2017 Disclosed to public


Blog Reference:
https://www.curesec.com/blog/article/blog/pfsense-232-XSS-197.html
 
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Curesec GmbH
Curesec Research Team
Josef-Orlopp-StraAe 54
10365 Berlin, Germany