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:  CSRF
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), the actions of creating and deleting firewall
rules are vulnerable to CSRF, enabling an Attacker to edit these rules with a
little bit of social engineering.

3. Details

CVSS: Medium; 5.4 https://www.first.org/cvss/calculator/3.0#CVSS:3.0/AV:N/AC:L/
PR:N/UI:R/S:U/C:N/I:L/A:L

Description: The easyrule.php script is vulnerable to CSRF, which allows an
attacker to create or delete firewall rules via CSRF.

Proof of Concept:

GET /easyrule.php?action=pass&int=LAN&proto=any&src=192.168.1.1&dst=192.168.1.1
&dstport=80&ipproto=inet

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-CSRF-198.html
 
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Curesec GmbH
Curesec Research Team
Josef-Orlopp-StraAe 54
10365 Berlin, Germany