PayPal GP+ Cross Site Scripting

`Title:  
======  
Paypal Bug Bounty #46 - Persistent Web Vulnerability  
  
  
Date:  
=====  
2013-03-28  
  
  
References:  
===========  
http://www.vulnerability-lab.com/get_content.php?id=805  
  
PayPal Security UID: esj1f86plc  
  
  
VL-ID:  
=====  
805  
  
  
Common Vulnerability Scoring System:  
====================================  
4.3  
  
  
Introduction:  
=============  
PayPal offers, both companies and individuals, a simple, quick and innovative solution of receiving money and making payments online.   
In ten years time, this company has become an authority in this market. Online buyers, eBay vendors, online stores and even the traditional   
offline companies. The number of users who trust PayPal with their transactions, continues to grow. 175 million PayPal accounts worldwide   
are certainly proof of that. PayPal uses a unique and extremely advanced system to prevent fraud, which guarantees a completely reliable   
and safe solution for real time payments online.  
  
GP+ objectively analyzes and assesses the quality and findablility of online stores and, at the same time, examines the possibilities to avoid   
attrition in the sales process. The base of this analysis is formed by: Google, Yahoo! and Microsoft Live, the W3C, Lipperhey in house research,   
governments, renowned trade publications, worldwide specialists pool and research done by PayPal into the characteristics of the most successful   
online stores worldwide.  
  
(Copy of the Vendor Homepage: https://www.paypal-gpplus.com/en/about/ )  
  
  
Abstract:  
=========  
The Vulnerability Laboratory Research Team discovered a web session vulnerability in the official PayPal GP+ Web Application Service.  
  
  
Report-Timeline:  
================  
2013-01-01: Researcher Notification & Coordination  
2013-01-02: Vendor Notification  
2013-01-12: Vendor Response/Feedback  
2013-03-26: Vendor Fix/Patch  
2013-03-28: Public Disclosure  
  
  
Status:  
========  
Published  
  
  
Affected Products:  
==================  
PayPal Inc  
Product: GP+ - Application Service 2013 Q1  
  
  
Exploitation-Technique:  
=======================  
Remote  
  
  
Severity:  
=========  
Medium  
  
  
Details:  
========  
A persistent input validation web vulnerability is detected in the official Paypal GP+ service application for anlayzing websites.  
  
The vulnerability is located in the pop up message of the delete button where the name of the website, that has been analyzed,   
is not sanitized, hence the malicious code gets executed. The delete button is located in two different places which are   
`Recent analysis` and `all analysis` listings. Exploitation of the vulnerability requires low user interaction.  
  
Successful exploitation of the vulnerability result in persistent session hijacking, persistent phishing, persistent external   
redirects, persistent external malware loads via inject and persistent vulnerable module web context manipulation.  
  
Vulnerable Section(s):  
[+] Paypal GP+ - (https://www.paypal-gpplus.com/en/dashboard/all/)  
  
Vulnerable Module(s):  
[+] Analyze a new website  
  
Vulnerable Parameter(s):  
[+] Website field out of the pop up message  
  
Affected Module(s):  
[+] Recent Analysis - All Analysis  
  
  
Proof of Concept:  
=================  
The vulnerability can be exploited by remote attackers without user interaction and without privileged application user account.  
For demonstration or reproduce ...  
  
PoC:   
The attacker should go and insert the malicious code in the field of the website he would like to search it. After that,   
he should click on "Scan URL". The scan will generate an error because the url is invalid, but when the user goes back to his dashboard   
and choose Recent Analysis/All Analysis, and he stops with his mouse pointer no the delete icon in the page, the malicious code will be executed.  
  
  
URL: https://www.paypal-gpplus.com/en/dashboard/all/  
  
Code Review:  
<td> </td>  
<td>  
<a href="https://www.paypal-gpplus.com/en/dashboard/analysis/2727753/"><[PERSISTENT INJECTED SCRIPT CODE!]<</a>   
</td>  
<td>  
<div class="more-options">  
</td>  
<td colspan="6">An error has occurred!</td>  
</tr>  
<tr id="tr-2727749" class="tr-row">  
<td> </td>  
<td>  
<a href="https://www.paypal-gpplus.com/en/dashboard/analysis/2727749/">"><[PERSISTENT INJECTED SCRIPT CODE!]</a>  
  
  
  
  
Risk:  
=====  
The security risk of the persistent input validation web vulnerability is estimated as medium(+).  
  
  
  
Credits:  
========  
Vulnerability Laboratory [Research Team] - Ibrahim El-Sayed (the_storm) [[email protected]] [iel-sayed.blogspot.com]  
  
  
  
Disclaimer:  
===========  
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--   
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`