Document Title:
===============
PayPal Inc Bug Bounty Issue #70 France - Persistent (Escape Shopping) Mail Vulnerability


References (Source):
====================
http://www.vulnerability-lab.com/get_content.php?id=869
http://vulnerability-db.com/magazine/articles/2014/09/30/paypal-inc-patched-several-persistent-mail-encoding-vulnerabilities

PayPal Security UID: Roc83bl


Release Date:
=============
2014-09-25


Vulnerability Laboratory ID (VL-ID):
====================================
869


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


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.

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 Vendor Homepage: www.paypal.com) [http://en.wikipedia.org/wiki/PayPal]


Abstract Advisory Information:
==============================
The Vulnerability Laboratory Research Team discovered a mail encoding web vulnerability in the official PayPal Inc France online service web-application


Vulnerability Disclosure Timeline:
==================================
2014-09-25:  Public Disclosure (Vulnerability Laboratory)


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


Affected Product(s):
====================
PayPal Inc
Product: France - Core Application 2013 Q1


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


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


Technical Details & Description:
================================
A persistent mail encoding web vulnerability has been discovered in the official PayPal Inc France Web Application Service.
The vulnerability allows remote attackers to inject own malicious script code to the application-side of a vulnerable module.

The persistent input validation mail encoding web vulnerability is located in the paypal france service application. Remote attacker 
can inject own script codes to POST method request of the vulnerable `invite a friend by mail` function. The vulnerable input values 
are name and company. The execution of the malicious injected code occurs in the outgoing invite service mail of the paypal france 
web-server. The service does not encode the input an transfers the malicious input wrong encoded through the invite service to execute 
in the mail as output. Remote attacker can tamper the session request (live) via POST to change the vulnerable values or exploit it 
manually by the form without secure validation or special char input restriction. 

The security risk of the persistent web vulnerability is estimated as medium with a cvss (common vulnerability scoring system) count of 3.5. 
Exploitation of the vulnerability requires no privileged application user account but low or medium user interaction. Successful exploitation 
of the vulnerability results in persistent phishing , session hijacking, persistent external redirect to malicious sources and persistent 
manipulation of connected or affected module context.


Request Method(s):
        [+] POST

Vulnerable Service(s):
        [+] PayPal Inc - France

Vulnerable Module(s):
        [+] Escape Shopping - Mail Notification

Vulnerable Parameter(s):
        [+] Name or Company

Affected Module(s):
        [+] Notification Mail (Web Server) [noreply@paypal.fr]


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

Code Review: Standard Notification Mail
<b>Bonjour  Benjamin 337</b><br /><br />
Damian   vous recommande un site vu sur l'Espace Shopping de PayPal :
<a href="http://www.flipstory.com" target="_blank">Flipstory</a>
<br /><br />Damian   a ajouté ce commentaire :<br /><i> </i><br />
<br /><br />Cet e-mail a été envoyé par l'intermédiaire de l'Espace Shopping PayPal par une personne estimant 
que ces informations sont susceptibles de vous intéresser. PayPal décline toute responsabilité quant à l'envoi et au contenu de cet e-mail.
<br /><br />
<b>L'équipe PayPal</b>


Topic:    XXX > vous recommande l'Espace Shopping de PayPal
Code Review:   Manipulated Notification Mail (Web Server) [noreply@paypal.fr]


PoC:
<b>Bonjour  "><[PERSISTENT INJECTED SCRIPT CODE!]"><&>lt;</b><br /><br />
Da  "><[PERSISTENT INJECTED SCRIPT CODE - PARSED!!]<  
vous recommande un site vu sur l'Espace Shopping de PayPal :
<a href="http://www.flipstory.com" target="_blank">Flipstory</a>

Sender Mail:
no-reply@paypal.fr

Test Account(s):
research@vulnerability-lab.com

Reference(s):
https://www.paypal-france.fr/espace-shopping/les-sites-bons-plans-PayPal/Toutes-les-categories/0/1


Solution - Fix & Patch:
=======================
The vulnerability can be patched by a secure parse and encode of the name and company input values.
Restrict and filter the output of the names that get streamed through the mail service to a customer or client to prevent persistent script code execution attacks.


Security Risk:
==============
The security risk of the persistent mail encoding (input validation) web vulnerability in the company and name values is estimated as medium. (Cvss 3.5)


Credits & Authors:
==================
Vulnerability Laboratory [Research Team] - Benjamin Kunz Mejri (bkm@evolution-sec.com) [www.vulnerability-lab.com]


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