AEF CMS v1.0.9 - (PM) Persistent Cross Site Scripting Vulnerability

[Vulnerability Lab <research@xxxxxxxxxxxxxxxxxxxxx>]

Document Title:
===============
AEF CMS v1.0.9 - (PM) Persistent Cross Site Scripting Vulnerability


References (Source):
====================
https://www.vulnerability-lab.com/get_content.php?id=2123



Release Date:
=============
2018-02-18


Vulnerability Laboratory ID (VL-ID):
====================================
2123


Common Vulnerability Scoring System:
====================================
4.4


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


Current Estimated Price:
========================
1.000€ - 2.000€


Product & Service Introduction:
===============================
AEFs full name is Advanced Electron Forum. This bulletin board software is free 
software. It is written 
in PHP and MySQL. AEF has a very simple and easy to use Administration Panel 
and installing this software 
is a piece of cake! You can install new themes, customize themes the way you 
want. The User Control Panel 
has a simple yet beautiful interface where users can set their preferences for 
the board. This Bulletin 
board or forum software has all the general features that a forum software 
should have.

(Copy of the Homepage: https://www.softaculous.com/apps/forums/AEF & 
http://www.anelectron.com/)


Abstract Advisory Information:
==============================
The vulnerability laboratory core research team discovered a persistent web 
vulnerability in the official Advanced Electron Forum v1.0.9 CMS.


Vulnerability Disclosure Timeline:
==================================
2018-02-20: Public Disclosure (Vulnerability Laboratory)



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


Affected Product(s):
====================

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


Severity Level:
===============
Medium


Authentication Type:
====================
Restricted authentication (user/moderator) - User privileges


User Interaction:
=================
Low User Interaction


Disclosure Type:
================
Independent Security Research


Technical Details & Description:
================================
A persistent cross site scripting vulnerability has been discovered in the 
official Advanced Electron Forums v1.0.9 Content Management System.
The vulnerability allows remote attackers to inject own malicious script code 
with persistent attack vector to the application-side of the service.

The persistent cross site vulnerability is located in the `FTP Link` element of 
the `Private Message` module. The editor of the private message 
module allows to insert links without sanitizing the content. Thus allows 
remote attackers to inject malicious script code payloads as private 
message to compromise user credentials or to persistent manipulate the affected 
modules context. The injection point is the editor ftp link 
element and the execution point occurs in the message body context on arrival. 
The request method to inject is post with restricted user 
privileges and the attack vector is located on the application-side.

Successful exploitation of the vulnerability results in session hijacking, 
persistent phishing attacks, persistent external redirects 
to malicious source and persistent manipulation of affected or connected 
application modules.

Request Method(s):
[+] POST

Vulnerable Module(s):
[+] Private Messages

Vulnerable Input(s):
[+] Ftp Link (Editor Element)


Proof of Concept (PoC):
=======================
The cross site scripting web vulnerability can be exploited by low privileged 
user accounts with low user interaction.
For security demonstration or to reproduce the vulnerability follow the 
provided information and steps below to continue.


Manual steps to reproduce the vulnerability ...
1. Open the web-application and login as user
2. Move to the private message module
3. Open up the editor by composing a message
4. add some short text, save the entry as draft
5. Open the draft and insert a ftp link with a script code payload
6. Save the entry and deliver the message to another test user
Note: The message only needs to be watched to execute on arrival
7. The test user opens the private message module and the persistent script 
code executes in the message body context
8. Successful reproduce of the persistent vulnerability!


PoC: Payload (Ftplink)
%0D%0A%0D%0A  or %0D%0A%0D%0A%0D%0A%0D%0A+


PoC: Vulnerable Source
<textarea name="pmbody" rows="13" cols="65" id="pmbody" 
onchange="storeCaret(this);" onkeyup="storeCaret(this);" 
onclick="storeCaret(this);" onselect="storeCaret(this);" style="visibility: 
visible; width: 487px; 
height: 
226px;">This+is+a+private+test+message+with+payload+in+the+ftp+link%0D%0A%0D%0A</textarea>


PoC: Session Logs (Send Private Message)
Status: 200[OK]
POST 
https://aeforums.localhost:8000/AEF/index.php?act=usercp&ucpact=sendsaved&pmid=1
 
        Mime Type[text/html]
   Request Header:
      Host[aeforums.localhost:8000]
      User-Agent[Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:56.0) 
Gecko/20100101 Firefox/56.0]
      Accept[text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8]
      Content-Type[application/x-www-form-urlencoded]
      Content-Length[174]
      
Referer[https://aeforums.localhost:8000/AEF/index.php?act=usercp&ucpact=sendsaved&pmid=1]
      Cookie[AEFCookies1526[aefsid]=jmik0sqtslneqffjl537i931brqh3tzr; 
AEFCookies8381[aefsid]=x1m0rs9lhcl6hl3tbq7qbdh9jn0xsnsf]
      Connection[keep-alive]
      Upgrade-Insecure-Requests[1]
   POST-Daten:
      pmrecipients[admin]
      pmsubject[test]
      
pmbody[This+is+a+private+test+message+with+payload+in+the+ftp+link%0D%0A%0D%0A]
      postcode[yerudyyk4joz8ea5]
      pmsaveinsentitems[on]
      sendpm[Send+PM]
   Response Header:
      Server[Apache]
      X-Powered-By[PHP/5.4.45]
      Content-Length[217]
      Content-Type[text/html; charset=ISO-8859-1]
-
Status: 200[OK]
GET https://aeforums.localhost:8000/AEF/evil.source 
        Mime Type[text/html]
   Request Header:
      Host[aeforums.localhost:8000]
      User-Agent[Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:56.0) 
Gecko/20100101 Firefox/56.0]
      Accept[text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8]
      
Referer[https://aeforums.localhost:8000/AEF/index.php?act=usercp&ucpact=sendsaved&pmid=1]
      Cookie[AEFCookies1526[aefsid]=jmik0sqtslneqffjl537i931brqh3tzr; 
AEFCookies8381[aefsid]=x1m0rs9lhcl6hl3tbq7qbdh9jn0xsnsf]
      Connection[keep-alive]
      Upgrade-Insecure-Requests[1]
   Response Header:
      Server[Apache]
      Accept-Ranges[bytes]
      Content-Length[431]
      Content-Type[text/html; charset=UTF-8]


Reference(s):
https://aeforums.localhost:8000/AEF/
https://aeforums.localhost:8000/AEF/index.php


Solution - Fix & Patch:
=======================
The security vulnerability can be patched by a sanitize of the ftp link element 
input field in the private message module.
Parse in the editor the output location for the link to prevent the execution 
point of the issue. 


Security Risk:
==============
The security risk of the persistent cross site scripting web vulnerability in 
the open-source web-application is estimated as medium (cvss 4.4).


Credits & Authors:
==================
Benjamin K.M. [research@xxxxxxxxxxxxxxxxxxxxx] - 
https://www.vulnerability-lab.com/show.php?user=Benjamin+K.M.


Disclaimer & Information:
=========================
The information provided in this advisory is provided as it is without any 
warranty. Vulnerability Lab disclaims all warranties, either expressed or 
implied, including the warranties of merchantability and capability for a 
particular purpose. Vulnerability-Lab or its suppliers are not liable in any 
case of damage, including direct, indirect, incidental, consequential loss of 
business profits or special damages, even if Vulnerability Labs or its 
suppliers have been advised of the possibility of such damages. Some states do 
not allow the exclusion or limitation of liability mainly for incidental
or consequential damages so the foregoing limitation may not apply. We do not 
approve or encourage anybody to break any licenses, policies, deface 
websites, hack into databases or trade with stolen data. We have no need for 
criminal activities or membership requests. We do not publish advisories 
or vulnerabilities of religious-, militant- and racist- 
hacker/analyst/researcher groups or individuals. We do not publish trade 
researcher mails, 
phone numbers, conversations or anything else to journalists, investigative 
authorities or private individuals. 

Domains:    www.vulnerability-lab.com           - www.vulnerability-db.com      
                                - www.evolution-sec.com
Programs:   vulnerability-lab.com/submit.php    - 
vulnerability-lab.com/list-of-bug-bounty-programs.php         - 
vulnerability-lab.com/register.php
Feeds:      vulnerability-lab.com/rss/rss.php   - 
vulnerability-lab.com/rss/rss_upcoming.php                    - 
vulnerability-lab.com/rss/rss_news.php
Social:     twitter.com/vuln_lab                - facebook.com/VulnerabilityLab 
                                - youtube.com/user/vulnerability0lab

Any modified copy or reproduction, including partially usages, of this file, 
resources or information requires authorization from Vulnerability Laboratory. 
Permission to electronically redistribute this alert in its unmodified form is 
granted. All other rights, including the use of other media, are reserved by 
Vulnerability Lab Research Team or its suppliers. All pictures, texts, 
advisories, source code, videos and other information on this website is 
trademark 
of vulnerability-lab team & the specific authors or managers. To record, list, 
modify, use or edit our material contact (admin@) to get an ask permission.

                                    Copyright © 2018 | Vulnerability Laboratory 
- [Evolution Security GmbH]™


-- 
VULNERABILITY LABORATORY - RESEARCH TEAM
SERVICE: www.vulnerability-lab.com