Message-ID: <5106A63C.10809@vulnerability-lab.com>
Date: Mon, 28 Jan 2013 17:24:28 +0100
From: Vulnerability Lab <research@...nerability-lab.com>
To: full-disclosure@...ts.grok.org.uk
Subject: Paypal Bug Bounty #10 - Persistent Web
	Vulnerability

Title:
======
Paypal Bug Bounty #10 - Persistent Web Vulnerability


Date:
=====
2013-01-24


References:
===========
http://www.vulnerability-lab.com/get_content.php?id=647

PayPal UID: ixb165sfi


VL-ID:
=====
647


Common Vulnerability Scoring System:
====================================
3.5


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.

On October 3, 2002, PayPal became a wholly owned subsidiary of eBay. Its corporate headquarters are in San Jose, California, United 
States at eBay s North First Street satellite office campus. The company also has significant operations in Omaha, Nebraska, Scottsdale, 
Arizona, and Austin, Texas, in the United States, Chennai, Dublin, Kleinmachnow (near Berlin) and Tel Aviv. As of July 2007, across 
Europe, PayPal also operates as a Luxembourg-based bank.

On March 17, 2010, PayPal entered into an agreement with China UnionPay (CUP), China s bankcard association, to allow Chinese consumers 
to use PayPal to shop online.PayPal is planning to expand its workforce in Asia to 2,000 by the end of the year 2010.
Between December 4ñ9, 2010, PayPal services were attacked in a series of denial-of-service attacks organized by Anonymous in retaliation 
for PayPal s decision to freeze the account of WikiLeaks citing terms of use violations over the publication of leaked US diplomatic cables.

(Copy of the Homepage: www.paypal.com) [http://en.wikipedia.org/wiki/PayPal]


Abstract:
=========
The Vulnerability Laboratory Research Team discovered a persistent Web Vulnerability in the official Paypal ecommerce website application.


Report-Timeline:
================
2012-07-06:	Researcher Notification & Coordination
2012-07-06:	Vendor Notification
2012-07-11:	Vendor Response/Feedback
2013-12-10:	Vendor Fix/Patch
2012-01-24:	Public Disclosure


Status:
========
Published


Affected Products:
==================
PayPal Inc
Product: PayPal Account Service Application 2012 Q4


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


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


Details:
========
A persistent input validation vulnerability is detected in the official Paypal ecommerce website content management system (Customer/Pro/Seller).
The bugs allow remote attackers to implement/inject malicious script code on the application side (persistent) of the paypal web service.

The vulnerability is located in the Geld buchen > Transcaction > Abbuchung prüfen module with the bound vulnerable bankname parameter. 
The bug affects the important Abbuchung prüfen listing of the paypal core application. The remote attacker can inject own the malicious 
script codes by requesting the transaction check page with a manipulated bankname parameter. 

The vulnerability can be exploited by remote attackers with low required user inter action and privileged Customer/Pro/Seller account.
Successful exploitation of the vulnerability can lead to session hijacking (customers), account steal via persistent web attack, persistent 
phishing or stable (persistent) web context manipulation of the vulnerable module.

Vulnerable Type(s):
                          [+] Customer/Pro/Seller Accounts

Vulnerable Section(s):
                          [+] Geld buchen > Transcaction > Abbuchung prüfen > Bankname

Vulnerable Module(s):
                          [+] Name der Bank (Name of Bank & Companyname)

Vulnerable Parameter(s):
                          [+] bankname

Affected Section(s):
			  [+] Abbuchung prüfen (Listing)


Proof of Concept:
=================
The vulnerability can be exploited by remote attackers with Customer/Pro/Seller Account & low required user inter action.
For demonstration or reproduce ...

Review: Geld buchen > Transcaction > Abbuchung prüfen (Listing)

<tbody><tr><th>Betrag</th><td>€0,80 EUR</td></tr><tr><th>Name des Kontoinhabers</th><td>Evolution Security</td></tr>
<tr><th>Name der Bank</th><td><[PERSISTENT INJECTED SCRIPT CODE!]"></td></tr><tr><th>Bankleitzahl</th><td>
51050352</td></tr><tr><th>Kontonummer</th><td>x-13371</td></tr>
</tbody></table></div>

URL Session:
https://www.paypal.com/de/cgi-bin/webscr?cmd=_flow&
SESSION=wbOxy2QWgxYBr5jKfOfH6E49y4duJ5yOQfN2yKqZgD-622kOCZZihkCZi7O&
dispatch=5885d80a66c0db1f8e263113d3faee8d2394db9703d295b4a2116480ee01a05c


Solution:
=========
Restrict the bankname input fields and parse with an exception handling or secure filter mask. 
Parse the bankname details output listing in Abbuchung prüfen (Listing) to prevent script code injects/executions.


Risk:
=====
The security risk of the persistent script code inject vulnerability is estimated as medium(+).


Credits:
========
Vulnerability Laboratory [Research Team]  -    Benjamin Kunz Mejri (bkm@...nerability-lab.com)


Disclaimer:
===========
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.

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