e107 v2 Bootstrap CMS - Cross Site Scripting Vulnerability

Document Title:
===============
e107 v2 Bootstrap CMS - Cross Site Scripting Vulnerability


References (Source):
====================
https://www.vulnerability-lab.com/get_content.php?id=2082


Release Date:
=============
2017-07-03


Vulnerability Laboratory ID (VL-ID):
====================================
2082


Common Vulnerability Scoring System:
====================================
3.3


Vulnerability Class:
====================
Cross Site Scripting - Non Persistent


Current Estimated Price:
========================
500€ - 1.000€


Product & Service Introduction:
===============================
Powerful Website Content Management System Designed for Bootstrap v3.
Get started and make e107 the engine of your fully-featured site today!

(Copy of the Vendors Page:  http://e107.org/ )




Abstract Advisory Information:
==============================
An independent vulnerability laboratory researcher discovered a cross site scripting vulnerability in the official e107 v2 Bootstrap content management system.


Vulnerability Disclosure Timeline:
==================================
2017-06-19: Researcher Notification & Coordination (Security Researcher)
2017-06-19: Vendor Notification (Security Department)
2017-07-03: Public Disclosure (Vulnerability Laboratory)


Discovery Status:
=================
Published


Affected Product(s):
====================
e107
Product: e107 Bootstrap - Content Management System 2.x


Exploitation Technique:
=======================
Remote


Severity Level:
===============
Low


Technical Details & Description:
================================
A cross site scripting web vulnerability has been discovered in the official e107 v2 Bootstrap content management system.
The cross site vulnerability allows remote attackers to inject own malicious script code to the client-side browser to 
web-application requests to compromise user credentials or session data.

The stored cross site vulnerability is located in the `tag` and `author` parameter of the `news.php` file  GET method request. 
Remote attackers are able to inject own malicious script codes to the client-side of the online service web-application to 
compromise user session information or session data.

The security risk of the cross site vulnerability is estimated as medium with a cvss (common vulnerability scoring system) count of 3.3.
Exploitation of the cross site scripting web vulnerability requires no privileged web-application user account and low user interaction. 
Successful exploitation results in session hijacking, non-persistent phishings attacks, non-persistent external redirect and malware 
loads or non-persistent manipulation of affected and connected module context.

Request Method(s):
[+] GET

Vulnerable File(s):
[+] news.php

Vulnerable Parameter(s):
[+] author
[+] tag


Proof of Concept (PoC):
=======================
The cross site vulnerability can be exploited by remote attackers without privileged user account and with low user interaction.
For security demonstration or to reproduce the vulnerability follow the provided information and steps below to continue.


PoC: Example
http://localhost:8080/e107/news.php?author=</title>[CROSS SITE SCRIPTING VULNERABILITY!]
http://localhost:8080/e107/news.php?tag=</title>[CROSS SITE SCRIPTING VULNERABILITY!]


PoC: Exploitation
1. http://localhost:8080/e107/news.php?author=%3C/title%3E%3Cimg%20src=evil.source%20onerror=prompt%28document.domain%29%3E
2. http://localhost:8080/e107/news.php?tag=%3C/title%3E%3Cimg%20src=evil.source%20onerror=prompt%28document.cookie%29%3E


Solution - Fix & Patch:
=======================
The vulnerability can be patched by checking and filtering the author and tag parameters from the vulnerable news.php file. 
Parse the output location of the parameter input to prevent exploitation of the vulnerability.


Security Risk:
==============
The security risk of the cross site scripting vulnerability in the content management system is estimated as medium (CVSS 3.3).



Credits & Authors:
==================
NirmalThapa [twitter.com/nirmal_4n_] - https://www.vulnerability-lab.com/show.php?user=NirmalThapa


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=========================
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