Document Title: =============== PayPal Bug Bounty #121 - Bypass & Persistent Vulnerability References (Source): ==================== http://www.vulnerability-lab.com/get_content.php?id=1627 ID: EIBBP-32725 Video: http://www.vulnerability-lab.com/get_content.php?id=1697 Release Date: ============= 2016-03-30 Vulnerability Laboratory ID (VL-ID): ==================================== 1627 Common Vulnerability Scoring System: ==================================== 3.9 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. (Copy of the Homepage: www.paypal.com) [http://en.wikipedia.org/wiki/PayPal] Abstract Advisory Information: ============================== The Vulnerability Laboratory Core Research Team discovered an application-side mail encoding web vulnerability and filter bypass issue in the official PayPal Inc online-service web-application. Vulnerability Disclosure Timeline: ================================== 2015-10-27: Researcher Notification & Coordination (Benjamin Kunz Mejri - Evolution Security GmbH) 2015-10-28: Vendor Notification (PayPal Inc - Security & Bug Bounty Team) 2015-10-30: Vendor Response/Feedback (PayPal Inc - Security & Bug Bounty Team) 2016-03-08: Vendor Fix/Patch (PayPal Inc - Developer Team) 2016-03-09: Security Acknowledgements (PayPal Inc - Security & Bug Bounty Team) 2016-03-30: Public Disclosure (Vulnerability Laboratory) Discovery Status: ================= Published Affected Product(s): ==================== PayPal Inc Product: PayPal - Online Service Web Application 2015 Q4 Exploitation Technique: ======================= Remote Severity Level: =============== Low Technical Details & Description: ================================ A persistent input validation & mail encoding web vulnerability has been discovered in the official PayPal Inc online-service web-application. The validation and mail encoding web vulnerability allows remote attackers to inject own malicious script codes to the mail header of the portal mails. Due to a long term testing we was able to verify with an older registered account a new vulnerability by accessing the panel. The accoutn x01445@gmail.com was registered with special chars in the ownername input fields. By registration of multiple emails to the account we was able to stream the malicious payload in the ownername of the account to another connected paypal user email (research@vulnerability-lab.com). The ownername input field does not encode the vulnerable inserted special chars. When an account is registered with an already exisiting account for sharing it is required to confirm the account by email (link). In this email the malicious injected owner-name payload is executing in the users account email inbox. The web-server of the paypal portal does not filter the input of the already injected code and uses a string to stream it internal to the registere account mail to verify. Thus results in the execution of the payload in the mail inbox of the target account that was added. The reply of the server does run through the main email sender of paypal (service@paypal.de). A filter has been activated by an automated appliance to make executable codes invisible after taking them to process by send as confirm email. In our testings every second email was manipulated by the server by injection of `div style=``display:none; color:fff; font-size:1pt;`. Even if the interaction was manual or automated coordinated to patch the validation flaw next to processing it we used another method to bypass. To bypass the filter then and edit the value=`` its required to update the owner name with payload to [payload]+input, and change it to value=`anything src=`/` so basically `anything` will be the value and src=``/`` will be the new parameter inside that input code form. The same way we used to confirm vulnerability 120 with the EIBBP-32718. The security risk of the persistent input validation web vulnerability is estimated as medium with a cvss (common vulnerability scoring system) count of 3.8. Exploitation of the persistent input validation web vulnerability requires a low privilege web-application user account and low user interaction. Successful exploitation of the vulnerability results in session hijacking, persistent phishing attacks, persistent redirect to external sources and persistent manipulation of affected or connected service module context. Request Method(s): Inject [+] POST Vulnerable Module(s): [+] PayPal Account - Profile Account Settings - Unconfirmed Email Account Vulnerable Parameter(s): [+] ownername Affected Module(s): [+] Confirm your Email Address (service@paypal.de or service@paypal.com) Proof of Concept (PoC): ======================= The application-side mail encoding vulnerability can be exploited by multi user account and shared accounts with restricted user account access and low or medium user interaction. For security demonstration or to reproduce the security vulnerability follow the provided information and steps below to continue. 1. Register a PayPal Inc account 2. Inject a payload as ownername to the paypal user profile 3. Use the bypass filter method to process the input 4. Surf to the profile were the emails becomes visible and click the unconfirmed flag button Note: Now the service takes the payload and streams the code to the paypal user email accounts 5. Open the postbox of one of the registered accounts that is still not confirmed and watch the header 6. The code executes in the header section next to the introduction sentence with the vulnerable ownername value 7. Successful reproduce of the security vulnerability! PoC: Source (Confirm Email Address) Confirm your email address ... Hello %20%20%20%20"><[PERSISTENT INJECTED SCRIPT CODE VULNERABILITY VIA OWNERNAME!]iframe src="a" onload="alert("VL")" <,<="" p="">

Confirm your email address now to let us know it really belongs to you.

Once that's done, you're ready to receive money.

If you are unable to click the button below to confirm your email, please follow this link https://www.paypal.com/de/ece/?cn=00622082609784738416&em=research@vulnerability-lab.com.

Confirm your email

Thanks,

PayPal

Copyright Â© 1999-2015 PayPal. All rights reserved. PayPal (Europe) S.Ã r.l. et Cie, S.C.A. SociÃ©tÃ© en Commandite par Actions Registered Office: 22â€“24 Boulevard Royal, L-2449 Luxembourg RCS Luxembourg B 118 349

Video Demonstration: ../poc.wmv In the video we demonstrate the compromised test account with multiple emails. One of the email is unconfirmed. In the profile of the user is a payload saved to the ownername of the paypal account. This ownername is taken to the confirm email of paypal and send by the original source. After the switch over to the system of the mobile device we extract the send message and save it as basic html file which results in an execution. The bug is located on the application-side and affects the email encoding to the paypal users. This issue could also have an effect to other section as well which has to be approved. The bypass method is to pass the bug through the filter for execution. Solution - Fix & Patch: ======================= 2016-03-08: Vendor Fix/Patch (PayPal Inc - Developer Team) Security Risk: ============== The security risk of the application-side mail encoding vulnerability and filter bypass issue is estimated as medium. (CVSS 3.7) Credits & Authors: ================== Vulnerability Laboratory [Research Team] - Benjamin Kunz Mejri (bkm@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. We do not approve or encourage anybody to break any vendor licenses, policies, deface websites, hack into databases or trade with fraud/stolen material. Domains: www.vulnerability-lab.com - www.vuln-lab.com - www.evolution-sec.com Contact: admin@vulnerability-lab.com - research@vulnerability-lab.com - admin@evolution-sec.com Section: magazine.vulnerability-db.com - vulnerability-lab.com/contact.php - evolution-sec.com/contact Social: twitter.com/#!/vuln_lab - facebook.com/VulnerabilityLab - youtube.com/user/vulnerability0lab Feeds: vulnerability-lab.com/rss/rss.php - vulnerability-lab.com/rss/rss_upcoming.php - vulnerability-lab.com/rss/rss_news.php Programs: vulnerability-lab.com/submit.php - vulnerability-lab.com/list-of-bug-bounty-programs.php - vulnerability-lab.com/register/ Any modified copy or reproduction, including partially usages, of this file requires authorization from Vulnerability Laboratory. Permission to electronically redistribute this alert in its unmodified form is granted. All other rights, including the use of other media, are reserved by Vulnerability-Lab Research Team or its suppliers. All pictures, texts, advisories, source code, videos and other information on this website is trademark of vulnerability-lab team & the specific authors or managers. To record, list (feed), modify, use or edit our material contact (admin@vulnerability-lab.com or research@vulnerability-lab.com) to get a permission. Copyright © 2016 | Vulnerability Laboratory - [Evolution Security GmbH]™

Query Builder