Document Title:
===============
PayPal Inc Bug Bounty- Filter Bypass & Arbitrary Code Execution Vulnerability
References (Source):
====================
http://www.vulnerability-lab.
Video: http://www.vulnerability-lab.
Vulnerability Magazine: http://magazine.vulnerability-
Release Date:
=============
2014-11-05
Vulnerability Laboratory ID (VL-ID):
==============================
936
Common Vulnerability Scoring System:
==============================
9.1
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.
(Copy of the Homepage: www.paypal.com) [http://en.wikipedia.org/wiki/
Abstract Advisory Information:
==============================
The Vulnerability Laboratory Research Team discovered a persistent script code injection web vulnerability in the official PayPal Inc core application.
Vulnerability Disclosure Timeline:
==============================
2013-04-25: Researcher Notification & Coordination (PayPal Inc - Bug Bounty Program)
2013-04-26: Vendor Notification (PayPal Inc - Bug Bounty Program)
2013-05-01: Vendor Response/Feedback (PayPal Inc - Bug Bounty Program)
2013-09-12: Vendor Response/Feedback (Ebay Inc - Bug Bounty Program)
2014-10-01: Vendor Response/Feedback (Ebay Inc - Bug Bounty Program)
2014-10-12: Vendor Fix/Patch (PayPal Inc - Developer Team)
2014-11-04: Public Disclosure (Vulnerability Laboratory)
Discovery Status:
=================
Published
Affected Product(s):
====================
PayPal Inc
Product: Core Application 2013 Q1
Exploitation Technique:
=======================
Remote
Severity Level:
===============
Critical
Technical Details & Description:
==============================
A system specific arbitrary code execution vulnerability has been discovered in the official in the official PayPal Inc Web-Application & API.
A filter bypass and persistent bug has also been revealed during the tests in the same vulnerable parameter location.
The system specific arbitrary code execution vulnerability is located in the developer api portal with connection and account access to the
paypal portal api. First the attacker registers an user account and includes to the `cardholder confidential` and `accountSelName` value own
malicious persistent script codes or local web-server files. To attack, the help center data of the malicious profile requires a second
registration to the developer api portal with same credentials (connected). The accountSelName and the confidential values are not limited
on input. The attacker is able to load script codes but can also remotly execute arbitrary codes to access local web-server files or configs.
The filter bypass occurs during the execution onclick by opening the profile. The trusted context of the dev api user account will be streamed
through the help center link on GET method requests. The regular filter of paypal prevents the external inject of frames to other websites but
in case of this issue the trusted context is directly executed on top of the profile. The execution and inject can occur remotly by attackers
and the attack typus is pending from persistent xss to arbitrary code execution and local web-server file request through the profile. The web-server
and misconfiguration allows the attacker to for example include a frame with a local request through the trusted context to capture unauthorized data
of the system. A webshell inject could also be possible during the execution point of the paypal users profile.
The attack vector is on the application-side of the paypal service and the injection request method is POST (dev api & help center). The security risk
of the local command/path inject vulnerability is estimated as medium with a cvss (common vulnerability scoring system) count of 9.1.
Exploitation of the system specific code execution vulnerability requires a low privileged paypal inc account with restricted access and no user interaction.
Successful exploitation of the vulnerability results in unauthorized execution of system specific codes, webshell injects via POST method, unauthorized path/file
value requests to compromise the application or the connected module components.
Request Method(s):
[+] POST
Vulnerable Module(s):
[+] helpcenter/home/ ( https://www.paypal.com/
[+] developer.paypal.com ( https://developer.paypal.com/
Vulnerable Parameter(s):
[+] accountSelName confidential
[+] confidential
Affected Module(s):
[+] PayPal Inc – Profile User Index (Main) – Execution through >
https://developer.paypal.com/
Proof of Concept (PoC):
=======================
The system specific code execution and persistent issue (filter bypass) can be exploited by remote attackers with low privileged application user account.
For security demonstration or to reproduce the security vulnerability follow the provided information and steps below to continue.
Manual Steps to reproduce the vulnerability ...
1. First register and account to the developer portal api
2. Second connect the paypal account to the help center by registration (2. to 1. also possible)
Note: On registration it`s required to include own payloads (code execution [path|file|config]or script code[html|php|js]) to the AccountSelName & cardholder confidential input.
3. Save the payload to your profile
4. Open the dev webportal & include the same data (payload) to your dev api profile values.
Note: On our tests we did but we are not if this is a requirement for a successful test.
5. Now surf to the following internal dev websitehttps://developer.
Note: On bottom of the page is now the paypal support link with the malicious injected code
6. Click the "Visit PayPal Support" link
7. The website redirect to the local paypal profile with the new api template theme. The system specific code execution occurs directly in the middle were the streamed data
of the helpcenter through dev api portal will become visible. The vulnerable executable values are `AccountSelName` and cardholder `confidential` account data.
Note: If you injected script code the script code execution on the main profile request throught the dev api service or a local config/file of the web-server will be loaded.
8. Successful reproduce of the remote vulnerability in the paypal infrastructure!
Note: DETAILS $ PAYPAL TO AUTHORIZED USAGE
Reference(s):
From < https://developer.paypal.com/
Through API > https://www.paypal.com/
To < https://www.paypal.com/
PoC: Help Center Index - confidential & accountSelName confidential
<div class="nav product merchant">
<div class="wrapper">
<div class="column_8_16" style="clear:both">
<div class="one column">
<div class="accountSelName confidential">
<div class="confidential" tabindex="0">%20>>"<<x>%20%20%
SPECIFIC CODE EXECUTION OR PERSISTENT SCRIPT CODE!]
</div>
</div>
Note: Code snippet poc shows the execution of the code after the inject of the test payloads
--- PoC-Session Logs [GET] (Vulnerable Service) ---
22:28:56.757[1073ms][total 1933ms] Status: 200[OK]
GET https://developer.paypal.com/
Flags[LOAD_DOCUMENT_URI LOAD_INITIAL_DOCUMENT_URI ] Content Size[2841]
Mime Type[text/html]
Request Headers:
Host[developer.paypal.com]
User-Agent[Mozilla/5.0 (Windows NT 6.1; WOW64; rv:20.0) Gecko/20100101 Firefox/20.0]
Accept[text/html,application/
Accept-Language[en-US,en;q=0.
Accept-Encoding[gzip, deflate] DNT[1]
Referer[https://developer.
Cookie[cookie_check=yes; analytics=
s_sess=%20c_m%3DNatural
%2520Searchpaypal%2520bug%2520
%3D0%3B%20tr_p1%
%252Fdashboard%252Ftest.dust%
%252Fdust%252Fdashboard%
%252Fweb-inf%252Ftmpl%
%3Dpaypalglobal%253D%
%2525252Ftmpl%2525252Fdust%
%25253D1%252526oid%
%2525252Fwebapps%
%20gpv_p23%3Dmain%253Amktg%
%7C1367009015468%3B%20s_fid%
%7C1430080136714%3B%20gpv_c43%
%252Fdust%252Fdashboard%
%2520value%7C1367009936725%3B; ts=vreXpYrS%3D1461678158%
%3D1367009181%26vr%
%
cwrClyrK4LoCV1fydGbAxiNL6iG=m_
MaEGDtkxeY34Bm2p_
sas9ZF4%
WNuEDFW%7cW-
7c1367007376; KHcl0EuY7AKSMgfvHl7J5E7hPtK=
consumer_display=USER_
%3d0%26USER_FILTER_CHOICE%3d0%
%3d1%26GIFT_BALANCE_MODULE_
%3d0%26SELLING_GROUP%3d1%
%3d1%26SHIPPING_GROUP%3d1%
%3d4294967295%26FORGOT_BUTTON_
Apache=10.74.8.156.
__utma=263370009.199482976.
__utmb=263370009.14.10.
__utmz=263370009.1367005657.1.
agzvbiaTG7XC5VaEwLQYUwrb15G=r_
dMpHqO7lRZspuKjGAkR9z7t5bcKMLz
fXNFERKV_Igy_
UbQb-
VIan06DHlaPDvMaBlO=
LpJ58GLANkKI5mfJmWwTdSARHKKlko
EuJAqV7lFBbj_KP8osHKEfkaCVs34_
M7mKxcPYdUTJlvDcNy2sbQiMWhHTh2
6re9gZQFjXSy6i979Lbe2UWIPZZnBC
niWkLTx17WhTjbpyVNE7O-wtjO9-
yENriXQtKsJGcXAm71RAiJwiJEWBkq
Q6YP1NY0Dp0B1531BjYZBrZbOAUh8m
_
EUNJ-6JqM4koqIvLZvDDo9_
HaC80bwXscjqZ7KM6VOxULOB534=
xlwWnFYuoFw1sPOG8KCzk6wz61BNsM
hD9krQVnGZvKKxHBuZd
hDMHGcgesSeWG; login_email=x01445%40gmail.com
jy0DcLqW37pTQNCEhLbqhA3QX00Bcw
BtISTVSGbl4WlJ-_
SEGM=
iJtY1GnpzN4Y-sixGy7BQ; navcmd=xpt%2fCustomer_Profile%
%2fSellerPreference;
pNTcMTtQfrJuaJiwEnWXQ6yNxfq=
axiyWkodDxxKi4R67QRG1M5Y9fj-
26PMeKw49jPMtad4WGiZRQSoayGXMs
MpZCtdFnUeh7VG8LcUYDbLPeIrziGR
Y2l18_FhlA9bLZKcbu7Hwv7-
navlns=0.0; INSIDE_SEARCH_PARAMS=2%3bDE%
SPARTAJSESSIONID=
Connection[keep-alive]
Response Headers:
Date[Fri, 26 Apr 2013 20:29:00 GMT]
Server[Apache-Coyote/1.1]
X-Frame-Options[SAMEORIGIN]
Cache-Control[must-revalidate, proxy-revalidate, no-cache]
Content-Type[text/html;
Content-Language[en-US] Set-Cookie[SPARTAJSESSIONID=
Domain=.paypal.com; Path=/; Secure; HttpOnly
HaC80bwXscjqZ7KM6VOxULOB534=
aIJwnTGse_O1jK-
QfPpYWWvNBLJ-jwrRCxbkqbW; Domain=.paypal.com; Path=/; Secure; HttpOnly
analytics=WlpqNFIvc5KQfH.5mTE.
CqpTh.
2033 16:44:19 GMT; Domain=.paypal.com; Path=/; Secure; HttpOnly
SPARTAJSESSIONIDV2=
2fIuBwSPPV1H3jNv3FOduHGSyqmykh
Max-Age=0; Expires=Thu, 01-Jan-1970 00:00:10 GMT; Domain=.paypal.com; Path=/; Secure;
HttpOnly]
Vary[Accept-Encoding]
Content-Encoding[gzip]
Content-Length[2841]
Keep-Alive[timeout=5, max=100]
Connection[Keep-Alive]
Note: The session log above with the GET method request shows the request which leads to the
execution in the next session-log. The server accepts the malicious and manipulated request and
redirects via referer and non expired session to the paypal.com portals were the execution occurs.
--- PoC Session Logs [GET] (Execution) ---
22:29:06.862[3380ms][total 3380ms] Status: 200[OK]
GET https://www.paypal.com/
Flags[LOAD_DOCUMENT_URI ] Content Size[5225] Mime Type[text/html]
Request Headers:
Host[www.paypal.com]
User-Agent[Mozilla/5.0 (Windows NT 6.1; WOW64; rv:20.0) Gecko/20100101 Firefox/20.0]
Accept[text/html,application/
Accept-Language[en-US,en;q=0.
Referer[https://www.paypal.
Cookie[Apache=10.73.8.62.
analytics=
ESn2IJ5J4WqpvQFrb.
%2520Searchpaypal%2520bug%2520
%20tr_p1%3Ddeveloperspartaweb%
%252Foverview.dust%3B%20lt%3D%
%252Fweb-inf%252Ftmpl%
s_pers=%20gpv_p23%3Dmain%
%7C1367009015468%3B%20s_fid%
%7C1430080143210%3B%20gpv_c43%
%252Fdust%252Fsupport%
%2520value%7C1367009943221%3B; bn_u=1332619451692973419; ts=vreXpYrS
%3D1461678158%26vteXpYrS%
%26vt%
cwrClyrK4LoCV1fydGbAxiNL6iG=m_
MaEGDtkxeY34Bm2p_
sas9ZF4%
WNuEDFW%7cW-
7c1367007376; KHcl0EuY7AKSMgfvHl7J5E7hPtK=
consumer_display=USER_
%3d0%26USER_FILTER_CHOICE%3d0%
%3d1%26GIFT_BALANCE_MODULE_
%3d0%26SELLING_GROUP%3d1%
%3d1%26SHIPPING_GROUP%3d1%
%3d4294967295%26FORGOT_BUTTON_
agzvbiaTG7XC5VaEwLQYUwrb15G=r_
dMpHqO7lRZspuKjGAkR9z7t5bcKMLz
fXNFERKV_Igy_
UbQb-
g2bQrGu--
VIan06DHlaPDvMaBlO=
LpJ58GLANkKI5mfJmWwTdSARHKKlko
EuJAqV7lFBbj_KP8osHKEfkaCVs34_
M7mKxcPYdUTJlvDcNy2sbQiMWhHTh2
6re9gZQFjXSy6i979Lbe2UWIPZZnBC
niWkLTx17WhTjbpyVNE7O-wtjO9-
yENriXQtKsJGcXAm71RAiJwiJEWBkq
Q6YP1NY0Dp0B1531BjYZBrZbOAUh8m
_
EUNJ-6JqM4koqIvLZvDDo9_
HaC80bwXscjqZ7KM6VOxULOB534=
5KhwiYVS1vwLn1Dh9NqoyWEOUWyUHV
Ehm; login_email=x01445%40gmail.com
LANG=en_US%3bDE; Gws4LBnVhSMuyYhD0wXzh01SEK=
jy0DcLqW37pTQNCEhLbqhA3QX00Bcw
BtISTVSGbl4WlJ-_
SEGM=
iJtY1GnpzN4Y-sixGy7BQ; X-PP-SILOVER=name%3DLIVE6.WEB.
%3D880%26app%3Dslingshot%
%2faccount%2fprofile%
pNTcMTtQfrJuaJiwEnWXQ6yNxfq=
axiyWkodDxxKi4R67QRG1M5Y9fj-
26PMeKw49jPMtad4WGiZRQSoayGXMs
MpZCtdFnUeh7VG8LcUYDbLPeIrziGR
Y2l18_FhlA9bLZKcbu7Hwv7-
navlns=0.0; INSIDE_SEARCH_PARAMS=2%3bDE%
tcs=main:identity:::newsso|_
SPARTAJSESSIONIDV2=
I25.tBKhyY-IJNPQ0A8Vw-
aksession=1367008449~id=
a0oGE8xfvt3ph8bjykqTbPzZj330+
MknMhGOK1SQUIF9uQ=] Connection[keep-alive]
Response Headers:
Server[Apache-Coyote/1.1]
X-Frame-Options[SAMEORIGIN]
Cache-Control[must-revalidate, proxy-revalidate, no-cache]
Content-Type[text/html;
Content-Language[en-US]
Content-Encoding[gzip]
Content-Length[5225]
Date[Fri, 26 Apr 2013 20:29:12 GMT]
Connection[keep-alive]
Vary[Accept-Encoding]
Set-Cookie[SPARTAJSESSIONID=
HttpOnlySPARTAJSESSIONID=
HaC80bwXscjqZ7KM6VOxULOB534=
RDYDMkpDjL9wnHZibXjZxPWxipETeT
FgpHVutAELsNqqk7uG; Domain=.paypal.com; Path=/; Secure; HttpOnly
analytics=0-
rm.LWF9zJC4dJEEJs; Max-Age=631138519; Expires=Tue, 26-Apr-2033
16:44:31 GMT; Domain=.paypal.com; Path=/; Secure; HttpOnly
SPARTAJSESSIONIDV2=
WFyBQE14Y1Em66vpfwGMDIo5ncV1LC
HttpOnly]
Note: The session logs above shows that the server accepted (200OK) the request and answers with the malicious code execution (GET) as response to me as user.
The service runs under the same origin policy which returns in the result of the dev through the help center. The execution can also be watched in the recorded
research video for the paypal bug bounty issue #88.
--- [ACCESS FOR PAYPAL]
Sandbox to Live Help Center Service > Account: ***********@gmail.com password: merlin23
1.png
The first image explains were the vulnerable location link has been placed after the inject for the
further execution of the code during the exploitation-phase. The system specific code execution or
persistent issue can be exploited by clicking the "Visit PayPal Support" link.
2.png
The second images shows were the code execution occurs inside of the paypal inc webapps core
and api. The code execution can be triggered by two vulnerable values via POST inject. To test we
injected two payloads own frame and one local request of a web-server config file. The execution of
the code occurs obviously next to the main user profile on index after the redirect to the referer.
3.png
The third picture shows were the code execution and persistent issue with filter bypass is located.
The vulnerable values are `confidential` and `accountSelName confidential`. Both values will be
taken through the filter via referer on a redirect request with the same origin policy setup. The
execution does not only allows to inject scipt codes for xss, the issue also allows an attacker to
request local web-server files by the trusted same origin policy context request.
4.png
The 4th image shows the session tamper details next to processing to clicking the link of the
developer portal (api) to paypal.com (paypal). The tampered session through moziall shows that the
server accepted the GET request with the further visible trusted context. The server responds with
200OK and directly executes the code through the paypal.com domain in the profile user top
section.
5.png
The 5th image shows were the code execution appears to become visible in the live session tamper.
The domain https://www.paypal.com/
was successfully because after the path ./helpcenter/home/[x] the code execution occurs after the
filter bypass through the other services.
6.png
The 6th images only shows that the attack vector of the issue in located on the application-side of the
paypal inc online service. Proof for check was multiple GET requests during the test from the
paypal database as user.
Solution - Fix & Patch:
=======================
A solution to fix the issue could be to parse all incoming values through the same origin policy configuration of the connected
portal with the same api. The vulnerable accountselname confidential and confidential values needs to be encoded even if transfered
through andother service location. Restrict the input for registration and disallow specialchars to prevent script code injects
and code execution payloads with unauthorized file requests through the trusted paypal home webapps context.
Note: The issue should be checked by the dev team to review also the backend effect of the issues. Issue is already marked as patched 2014Q4.
Security Risk:
==============
The security risk of the of the arbitrary code execution in the confidential account value GET method request is estimated as critical. (CVSS 9.1)
Attacker can request local path values by implementation of privileged context reuqest in the referer which results in a system compromise because of
attackers are able to access unauthorized server local files.
Credits & Authors:
==================
Vulnerability Laboratory [Research Team] - Benjamin Kunz Mejri (bkm@vulnerability-lab.com)
Disclaimer & Information:
=========================
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BUSINESS: www.evolution-sec.com
===============
PayPal Inc Bug Bounty- Filter Bypass & Arbitrary Code Execution Vulnerability
References (Source):
====================
http://www.vulnerability-lab.
Video: http://www.vulnerability-lab.
Vulnerability Magazine: http://magazine.vulnerability-
Release Date:
=============
2014-11-05
Vulnerability Laboratory ID (VL-ID):
==============================
936
Common Vulnerability Scoring System:
==============================
9.1
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.
(Copy of the Homepage: www.paypal.com) [http://en.wikipedia.org/wiki/
Abstract Advisory Information:
==============================
The Vulnerability Laboratory Research Team discovered a persistent script code injection web vulnerability in the official PayPal Inc core application.
Vulnerability Disclosure Timeline:
==============================
2013-04-25: Researcher Notification & Coordination (PayPal Inc - Bug Bounty Program)
2013-04-26: Vendor Notification (PayPal Inc - Bug Bounty Program)
2013-05-01: Vendor Response/Feedback (PayPal Inc - Bug Bounty Program)
2013-09-12: Vendor Response/Feedback (Ebay Inc - Bug Bounty Program)
2014-10-01: Vendor Response/Feedback (Ebay Inc - Bug Bounty Program)
2014-10-12: Vendor Fix/Patch (PayPal Inc - Developer Team)
2014-11-04: Public Disclosure (Vulnerability Laboratory)
Discovery Status:
=================
Published
Affected Product(s):
====================
PayPal Inc
Product: Core Application 2013 Q1
Exploitation Technique:
=======================
Remote
Severity Level:
===============
Critical
Technical Details & Description:
==============================
A system specific arbitrary code execution vulnerability has been discovered in the official in the official PayPal Inc Web-Application & API.
A filter bypass and persistent bug has also been revealed during the tests in the same vulnerable parameter location.
The system specific arbitrary code execution vulnerability is located in the developer api portal with connection and account access to the
paypal portal api. First the attacker registers an user account and includes to the `cardholder confidential` and `accountSelName` value own
malicious persistent script codes or local web-server files. To attack, the help center data of the malicious profile requires a second
registration to the developer api portal with same credentials (connected). The accountSelName and the confidential values are not limited
on input. The attacker is able to load script codes but can also remotly execute arbitrary codes to access local web-server files or configs.
The filter bypass occurs during the execution onclick by opening the profile. The trusted context of the dev api user account will be streamed
through the help center link on GET method requests. The regular filter of paypal prevents the external inject of frames to other websites but
in case of this issue the trusted context is directly executed on top of the profile. The execution and inject can occur remotly by attackers
and the attack typus is pending from persistent xss to arbitrary code execution and local web-server file request through the profile. The web-server
and misconfiguration allows the attacker to for example include a frame with a local request through the trusted context to capture unauthorized data
of the system. A webshell inject could also be possible during the execution point of the paypal users profile.
The attack vector is on the application-side of the paypal service and the injection request method is POST (dev api & help center). The security risk
of the local command/path inject vulnerability is estimated as medium with a cvss (common vulnerability scoring system) count of 9.1.
Exploitation of the system specific code execution vulnerability requires a low privileged paypal inc account with restricted access and no user interaction.
Successful exploitation of the vulnerability results in unauthorized execution of system specific codes, webshell injects via POST method, unauthorized path/file
value requests to compromise the application or the connected module components.
Request Method(s):
[+] POST
Vulnerable Module(s):
[+] helpcenter/home/ ( https://www.paypal.com/
[+] developer.paypal.com ( https://developer.paypal.com/
Vulnerable Parameter(s):
[+] accountSelName confidential
[+] confidential
Affected Module(s):
[+] PayPal Inc – Profile User Index (Main) – Execution through >
https://developer.paypal.com/
Proof of Concept (PoC):
=======================
The system specific code execution and persistent issue (filter bypass) can be exploited by remote attackers with low privileged application user account.
For security demonstration or to reproduce the security vulnerability follow the provided information and steps below to continue.
Manual Steps to reproduce the vulnerability ...
1. First register and account to the developer portal api
2. Second connect the paypal account to the help center by registration (2. to 1. also possible)
Note: On registration it`s required to include own payloads (code execution [path|file|config]or script code[html|php|js]) to the AccountSelName & cardholder confidential input.
3. Save the payload to your profile
4. Open the dev webportal & include the same data (payload) to your dev api profile values.
Note: On our tests we did but we are not if this is a requirement for a successful test.
5. Now surf to the following internal dev websitehttps://developer.
Note: On bottom of the page is now the paypal support link with the malicious injected code
6. Click the "Visit PayPal Support" link
7. The website redirect to the local paypal profile with the new api template theme. The system specific code execution occurs directly in the middle were the streamed data
of the helpcenter through dev api portal will become visible. The vulnerable executable values are `AccountSelName` and cardholder `confidential` account data.
Note: If you injected script code the script code execution on the main profile request throught the dev api service or a local config/file of the web-server will be loaded.
8. Successful reproduce of the remote vulnerability in the paypal infrastructure!
Note: DETAILS $ PAYPAL TO AUTHORIZED USAGE
Reference(s):
From < https://developer.paypal.com/
Through API > https://www.paypal.com/
To < https://www.paypal.com/
PoC: Help Center Index - confidential & accountSelName confidential
<div class="nav product merchant">
<div class="wrapper">
<div class="column_8_16" style="clear:both">
<div class="one column">
<div class="accountSelName confidential">
<div class="confidential" tabindex="0">%20>>"<<x>%20%20%
SPECIFIC CODE EXECUTION OR PERSISTENT SCRIPT CODE!]
</div>
</div>
Note: Code snippet poc shows the execution of the code after the inject of the test payloads
--- PoC-Session Logs [GET] (Vulnerable Service) ---
22:28:56.757[1073ms][total 1933ms] Status: 200[OK]
GET https://developer.paypal.com/
Flags[LOAD_DOCUMENT_URI LOAD_INITIAL_DOCUMENT_URI ] Content Size[2841]
Mime Type[text/html]
Request Headers:
Host[developer.paypal.com]
User-Agent[Mozilla/5.0 (Windows NT 6.1; WOW64; rv:20.0) Gecko/20100101 Firefox/20.0]
Accept[text/html,application/
Accept-Language[en-US,en;q=0.
Accept-Encoding[gzip, deflate] DNT[1]
Referer[https://developer.
Cookie[cookie_check=yes; analytics=
s_sess=%20c_m%3DNatural
%2520Searchpaypal%2520bug%2520
%3D0%3B%20tr_p1%
%252Fdashboard%252Ftest.dust%
%252Fdust%252Fdashboard%
%252Fweb-inf%252Ftmpl%
%3Dpaypalglobal%253D%
%2525252Ftmpl%2525252Fdust%
%25253D1%252526oid%
%2525252Fwebapps%
%20gpv_p23%3Dmain%253Amktg%
%7C1367009015468%3B%20s_fid%
%7C1430080136714%3B%20gpv_c43%
%252Fdust%252Fdashboard%
%2520value%7C1367009936725%3B; ts=vreXpYrS%3D1461678158%
%3D1367009181%26vr%
%
cwrClyrK4LoCV1fydGbAxiNL6iG=m_
MaEGDtkxeY34Bm2p_
sas9ZF4%
WNuEDFW%7cW-
7c1367007376; KHcl0EuY7AKSMgfvHl7J5E7hPtK=
consumer_display=USER_
%3d0%26USER_FILTER_CHOICE%3d0%
%3d1%26GIFT_BALANCE_MODULE_
%3d0%26SELLING_GROUP%3d1%
%3d1%26SHIPPING_GROUP%3d1%
%3d4294967295%26FORGOT_BUTTON_
Apache=10.74.8.156.
__utma=263370009.199482976.
__utmb=263370009.14.10.
__utmz=263370009.1367005657.1.
agzvbiaTG7XC5VaEwLQYUwrb15G=r_
dMpHqO7lRZspuKjGAkR9z7t5bcKMLz
fXNFERKV_Igy_
UbQb-
VIan06DHlaPDvMaBlO=
LpJ58GLANkKI5mfJmWwTdSARHKKlko
EuJAqV7lFBbj_KP8osHKEfkaCVs34_
M7mKxcPYdUTJlvDcNy2sbQiMWhHTh2
6re9gZQFjXSy6i979Lbe2UWIPZZnBC
niWkLTx17WhTjbpyVNE7O-wtjO9-
yENriXQtKsJGcXAm71RAiJwiJEWBkq
Q6YP1NY0Dp0B1531BjYZBrZbOAUh8m
_
EUNJ-6JqM4koqIvLZvDDo9_
HaC80bwXscjqZ7KM6VOxULOB534=
xlwWnFYuoFw1sPOG8KCzk6wz61BNsM
hD9krQVnGZvKKxHBuZd
hDMHGcgesSeWG; login_email=x01445%40gmail.com
jy0DcLqW37pTQNCEhLbqhA3QX00Bcw
BtISTVSGbl4WlJ-_
SEGM=
iJtY1GnpzN4Y-sixGy7BQ; navcmd=xpt%2fCustomer_Profile%
%2fSellerPreference;
pNTcMTtQfrJuaJiwEnWXQ6yNxfq=
axiyWkodDxxKi4R67QRG1M5Y9fj-
26PMeKw49jPMtad4WGiZRQSoayGXMs
MpZCtdFnUeh7VG8LcUYDbLPeIrziGR
Y2l18_FhlA9bLZKcbu7Hwv7-
navlns=0.0; INSIDE_SEARCH_PARAMS=2%3bDE%
SPARTAJSESSIONID=
Connection[keep-alive]
Response Headers:
Date[Fri, 26 Apr 2013 20:29:00 GMT]
Server[Apache-Coyote/1.1]
X-Frame-Options[SAMEORIGIN]
Cache-Control[must-revalidate, proxy-revalidate, no-cache]
Content-Type[text/html;
Content-Language[en-US] Set-Cookie[SPARTAJSESSIONID=
Domain=.paypal.com; Path=/; Secure; HttpOnly
HaC80bwXscjqZ7KM6VOxULOB534=
aIJwnTGse_O1jK-
QfPpYWWvNBLJ-jwrRCxbkqbW; Domain=.paypal.com; Path=/; Secure; HttpOnly
analytics=WlpqNFIvc5KQfH.5mTE.
CqpTh.
2033 16:44:19 GMT; Domain=.paypal.com; Path=/; Secure; HttpOnly
SPARTAJSESSIONIDV2=
2fIuBwSPPV1H3jNv3FOduHGSyqmykh
Max-Age=0; Expires=Thu, 01-Jan-1970 00:00:10 GMT; Domain=.paypal.com; Path=/; Secure;
HttpOnly]
Vary[Accept-Encoding]
Content-Encoding[gzip]
Content-Length[2841]
Keep-Alive[timeout=5, max=100]
Connection[Keep-Alive]
Note: The session log above with the GET method request shows the request which leads to the
execution in the next session-log. The server accepts the malicious and manipulated request and
redirects via referer and non expired session to the paypal.com portals were the execution occurs.
--- PoC Session Logs [GET] (Execution) ---
22:29:06.862[3380ms][total 3380ms] Status: 200[OK]
GET https://www.paypal.com/
Flags[LOAD_DOCUMENT_URI ] Content Size[5225] Mime Type[text/html]
Request Headers:
Host[www.paypal.com]
User-Agent[Mozilla/5.0 (Windows NT 6.1; WOW64; rv:20.0) Gecko/20100101 Firefox/20.0]
Accept[text/html,application/
Accept-Language[en-US,en;q=0.
Referer[https://www.paypal.
Cookie[Apache=10.73.8.62.
analytics=
ESn2IJ5J4WqpvQFrb.
%2520Searchpaypal%2520bug%2520
%20tr_p1%3Ddeveloperspartaweb%
%252Foverview.dust%3B%20lt%3D%
%252Fweb-inf%252Ftmpl%
s_pers=%20gpv_p23%3Dmain%
%7C1367009015468%3B%20s_fid%
%7C1430080143210%3B%20gpv_c43%
%252Fdust%252Fsupport%
%2520value%7C1367009943221%3B; bn_u=1332619451692973419; ts=vreXpYrS
%3D1461678158%26vteXpYrS%
%26vt%
cwrClyrK4LoCV1fydGbAxiNL6iG=m_
MaEGDtkxeY34Bm2p_
sas9ZF4%
WNuEDFW%7cW-
7c1367007376; KHcl0EuY7AKSMgfvHl7J5E7hPtK=
consumer_display=USER_
%3d0%26USER_FILTER_CHOICE%3d0%
%3d1%26GIFT_BALANCE_MODULE_
%3d0%26SELLING_GROUP%3d1%
%3d1%26SHIPPING_GROUP%3d1%
%3d4294967295%26FORGOT_BUTTON_
agzvbiaTG7XC5VaEwLQYUwrb15G=r_
dMpHqO7lRZspuKjGAkR9z7t5bcKMLz
fXNFERKV_Igy_
UbQb-
g2bQrGu--
VIan06DHlaPDvMaBlO=
LpJ58GLANkKI5mfJmWwTdSARHKKlko
EuJAqV7lFBbj_KP8osHKEfkaCVs34_
M7mKxcPYdUTJlvDcNy2sbQiMWhHTh2
6re9gZQFjXSy6i979Lbe2UWIPZZnBC
niWkLTx17WhTjbpyVNE7O-wtjO9-
yENriXQtKsJGcXAm71RAiJwiJEWBkq
Q6YP1NY0Dp0B1531BjYZBrZbOAUh8m
_
EUNJ-6JqM4koqIvLZvDDo9_
HaC80bwXscjqZ7KM6VOxULOB534=
5KhwiYVS1vwLn1Dh9NqoyWEOUWyUHV
Ehm; login_email=x01445%40gmail.com
LANG=en_US%3bDE; Gws4LBnVhSMuyYhD0wXzh01SEK=
jy0DcLqW37pTQNCEhLbqhA3QX00Bcw
BtISTVSGbl4WlJ-_
SEGM=
iJtY1GnpzN4Y-sixGy7BQ; X-PP-SILOVER=name%3DLIVE6.WEB.
%3D880%26app%3Dslingshot%
%2faccount%2fprofile%
pNTcMTtQfrJuaJiwEnWXQ6yNxfq=
axiyWkodDxxKi4R67QRG1M5Y9fj-
26PMeKw49jPMtad4WGiZRQSoayGXMs
MpZCtdFnUeh7VG8LcUYDbLPeIrziGR
Y2l18_FhlA9bLZKcbu7Hwv7-
navlns=0.0; INSIDE_SEARCH_PARAMS=2%3bDE%
tcs=main:identity:::newsso|_
SPARTAJSESSIONIDV2=
I25.tBKhyY-IJNPQ0A8Vw-
aksession=1367008449~id=
a0oGE8xfvt3ph8bjykqTbPzZj330+
MknMhGOK1SQUIF9uQ=] Connection[keep-alive]
Response Headers:
Server[Apache-Coyote/1.1]
X-Frame-Options[SAMEORIGIN]
Cache-Control[must-revalidate, proxy-revalidate, no-cache]
Content-Type[text/html;
Content-Language[en-US]
Content-Encoding[gzip]
Content-Length[5225]
Date[Fri, 26 Apr 2013 20:29:12 GMT]
Connection[keep-alive]
Vary[Accept-Encoding]
Set-Cookie[SPARTAJSESSIONID=
HttpOnlySPARTAJSESSIONID=
HaC80bwXscjqZ7KM6VOxULOB534=
RDYDMkpDjL9wnHZibXjZxPWxipETeT
FgpHVutAELsNqqk7uG; Domain=.paypal.com; Path=/; Secure; HttpOnly
analytics=0-
rm.LWF9zJC4dJEEJs; Max-Age=631138519; Expires=Tue, 26-Apr-2033
16:44:31 GMT; Domain=.paypal.com; Path=/; Secure; HttpOnly
SPARTAJSESSIONIDV2=
WFyBQE14Y1Em66vpfwGMDIo5ncV1LC
HttpOnly]
Note: The session logs above shows that the server accepted (200OK) the request and answers with the malicious code execution (GET) as response to me as user.
The service runs under the same origin policy which returns in the result of the dev through the help center. The execution can also be watched in the recorded
research video for the paypal bug bounty issue #88.
--- [ACCESS FOR PAYPAL]
Sandbox to Live Help Center Service > Account: ***********@gmail.com password: merlin23
1.png
The first image explains were the vulnerable location link has been placed after the inject for the
further execution of the code during the exploitation-phase. The system specific code execution or
persistent issue can be exploited by clicking the "Visit PayPal Support" link.
2.png
The second images shows were the code execution occurs inside of the paypal inc webapps core
and api. The code execution can be triggered by two vulnerable values via POST inject. To test we
injected two payloads own frame and one local request of a web-server config file. The execution of
the code occurs obviously next to the main user profile on index after the redirect to the referer.
3.png
The third picture shows were the code execution and persistent issue with filter bypass is located.
The vulnerable values are `confidential` and `accountSelName confidential`. Both values will be
taken through the filter via referer on a redirect request with the same origin policy setup. The
execution does not only allows to inject scipt codes for xss, the issue also allows an attacker to
request local web-server files by the trusted same origin policy context request.
4.png
The 4th image shows the session tamper details next to processing to clicking the link of the
developer portal (api) to paypal.com (paypal). The tampered session through moziall shows that the
server accepted the GET request with the further visible trusted context. The server responds with
200OK and directly executes the code through the paypal.com domain in the profile user top
section.
5.png
The 5th image shows were the code execution appears to become visible in the live session tamper.
The domain https://www.paypal.com/
was successfully because after the path ./helpcenter/home/[x] the code execution occurs after the
filter bypass through the other services.
6.png
The 6th images only shows that the attack vector of the issue in located on the application-side of the
paypal inc online service. Proof for check was multiple GET requests during the test from the
paypal database as user.
Solution - Fix & Patch:
=======================
A solution to fix the issue could be to parse all incoming values through the same origin policy configuration of the connected
portal with the same api. The vulnerable accountselname confidential and confidential values needs to be encoded even if transfered
through andother service location. Restrict the input for registration and disallow specialchars to prevent script code injects
and code execution payloads with unauthorized file requests through the trusted paypal home webapps context.
Note: The issue should be checked by the dev team to review also the backend effect of the issues. Issue is already marked as patched 2014Q4.
Security Risk:
==============
The security risk of the of the arbitrary code execution in the confidential account value GET method request is estimated as critical. (CVSS 9.1)
Attacker can request local path values by implementation of privileged context reuqest in the referer which results in a system compromise because of
attackers are able to access unauthorized server local files.
Credits & Authors:
==================
Vulnerability Laboratory [Research Team] - Benjamin Kunz Mejri (bkm@vulnerability-lab.com)
Disclaimer & Information:
=========================
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