Document Title: =============== Paypal BB #108 MOS - Bypass & Persistent Vulnerability References (Source): ==================== http://www.vulnerability-lab.com/get_content.php?id=1049 PayPal Security UID: qw115bSN Video: http://www.vulnerability-lab.com/get_content.php?id=1273 Video Demonstration: www.youtube.com/watch?v=GRvU_sKWkIs Release Date: ============= 2014-07-08 Vulnerability Laboratory ID (VL-ID): ==================================== 1049 Common Vulnerability Scoring System: ==================================== 4.1 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. 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 Advisory Information: ============================== The Vulnerability Laboratory Research Team has discovered a filter bypass & persistent Web Vulnerability on Paypal Core web application. Vulnerability Disclosure Timeline: ================================== 2013-08-15: Researcher Notification & Coordination (Ateeq ur Rehman Khan - VL Core Research Team) 2013-08-16: Vendor Notification (PayPal Site Security Team - Bug Bounty Program) 2013-12-22: Vendor Response/Feedback (PayPal Site Security Team - Bug Bounty Program) 2014-05-15: Vendor Fix/Patch (PayPal Inc Developer Team) 2014-07-09: Public Disclosure (Vulnerability Laboratory) Discovery Status: ================= Published Affected Product(s): ==================== PayPal Inc Product: Shipping & MOS Application - API 2013 Q2 Exploitation Technique: ======================= Remote Severity Level: =============== Medium Technical Details & Description: ================================ A filter bypass and persistent script code injection vulnerability is detected in the official Paypal service application and common service api. The vulnerability allows an attacker to inject own malicious script codes on application-side (persistent) of the vulnerable module/function. The vulnerability has been discovered in the Paypal MOS (Multi Order Shipping) web application (https://ship.paypal.com). The vulnerability exists in the `Ship To Address` section while creating a new order and the vulnerable fields are `First name` and `Last Name`. During the testing, the researcher was able to bypass the current security filters (client side input validation) by intercepting the POST requests and injecting the payloads directly instead of using the web interface. Affected URL is pasted below for your reference: https://ship.paypal.com/cgi-bin/shipweb?cmd=create-shipment The affected Parameters are: FirstName LastName The payload used during the testing is: ![CDATA[iframe src=evil.source onload=alert(`POC-NEW-Ateeq`)]] The vulnerability is exploitable for stand alone user account but also for multi-accounts in paypal. The way of exploitation is remote and the risk is high because of the following scenario. A remote attacker is able to create multiple customer orders with injected payloads. When the admin merchant account user logs in and checks the Paypal Multi Online Shipping Orders, the exploit gets triggered. Exploitation of the persistent web vulnerability requires a low privileged paypal application user account and only low user interaction. Successful exploitation of the vulnerability results in persistent session hijacking, persistent phishing, persistent external redirects, persistent external malware loads via inject and persistent module web context manipulation. Vulnerable Section(s): [+] Paypal API - (https://www.paypal.com/en) Vulnerable Module(s): [+] Create New Order - Ship To Vulnerable Field(s): [+] First Name [+] Last Name Proof of Concept (PoC): ======================= The persistent input validation vulnerability can be exploited by remote attackers with low user interaction. Requirement(s): You need two accounts to produce this PoC, #1 the Main Business Account and #2, the second low privileged user with limited access to only Paypal Multi Online Shipping Module. To reproduce the vulnerability you need to follow the below mentioned manual steps ... 1. Go to https://www.paypal.com/us/cgi-bin/webscr?cmd=_bulk-ship and Login as the Low Priviledged user. 2. After successfully logging in, you should have the Paypal Multi Shipping window popped up. 3. Click on "Continue" and you will reach to the main MOS web application. 4. On the Get Started page, you will have two options, #1 to import and #2 to Create. Click on Create 5. Click on "Ship To Address" to expand all input fields. 6. Fill up all input fields with dummy data and before clicking save and close, Intercept the POST request using Tamper data or any other http proxy intercepting tool 5. Fill dummy data in all other fields (I used digits only during the POC) 6. Intercept the POST request and enter the payload under the Firstname and Last name and click OK 7. Refresh your browser and you should be able to see a Javascript popup proving the existence of this vulnerability. Poc: Payload ]]> --- PoC Session Logs [POST] --- POST /cgi-bin/shipweb?cmd=create-shipment HTTP/1.1 Host: ship.paypal.com User-Agent: Mozilla/5.0 (Windows NT 6.1; WOW64; rv:22.0) Gecko/20100101 Firefox/22.0 Accept: text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8 Accept-Language: en-US,en;q=0.5 Accept-Encoding: gzip, deflate DNT: 1 Content-Type: text/xml; charset=UTF-8 Referer: https://ship.paypal.com/powership/shipping/dialogs/create/create.html?version=1_0_4 Content-Length: 1017 Cookie: [HIDDEN] Connection: keep-alive Pragma: no-cache Cache-Control: no-cache MBYAX9TQRRXHL ]]> ]]> AK 8XE38925VR9032019 0 false 000000 false false true Response Logs: HTTP/1.1 200 OK Date: Thu, 15 Aug 2013 22:49:54 GMT Server: Apache X-Frame-Options: SAMEORIGIN Set-Cookie: RouxWyWiKm3aD3COV0dah-P3yUq=LuZkeZYc_-9QH4IOUBbh_E8SdiYgOXCjL_UnXSxRJZLcLIBjBrKoxeEw80_IS0efTrI0ZtfUpgKJRRe0MkwLPYNjvaEm9N9tVSYtjDrpnRInb1kK; domain=.paypal.com; path=/; Secure; HttpOnly Connection: close Content-Type: text/xml Content-Length: 299 BS-1DS20715V1016433V 7HJ56070690027340 false 0 Reference(s): https://www.paypal.com/us/cgi-bin/webscr?cmd=_bulk-ship https://ship.paypal.com/ Solution - Fix & Patch: ======================= Input validation should be performed not just on client side but also on the server end before allowing the entries to be saved into the database to mitigate any further risks associated with this vulnerability. Security Risk: ============== The security risk of the persistent script code inject vulnerability is estimated as medium(+). Credits & Authors: ================== Vulnerability Laboratory [Research Team] - Ateeq ur Rehman Khan (ateeq@evolution-sec.com) [www.vulnerability-lab.com] Disclaimer & Information: ========================= 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. 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