Document Title: =============== PayPal Inc Bug Bounty #42 - Persistent POST Inject Vulnerability References (Source): ==================== http://www.vulnerability-lab.com/get_content.php?id=801 PayPal Security UID: kxy1ea5ech Release Date: ============= 2013-11-18 Vulnerability Laboratory ID (VL-ID): ==================================== 801 Common Vulnerability Scoring System: ==================================== 3.5 Product & Service Introduction: =============================== Als spezialisierte Factoringgesellschaft fr die Abwicklung von Rechnungskauf-Zahlungen im Internet wurde die BillSAFE GmbH 2008 durch die Altgesellschafter der mediafinanz AG gegrndet. Das Management der BillSAFE GmbH besteht ausnahmslos aus Risikomanagement-Experten mit jahrelanger Erfahrung aus der Betreuung von namhaften Online-Shops und Versandhandelsunternehmen. 2009 erfolgte die regulre Inbetriebnahme des Services mit der Anbindung der ersten 100 Online-Shops. 2010 beteiligte sich die eBay Tochter PayPal im Rahmen einer strategischen Partnerschaft an der BillSAFE GmbH. 2011 wurde ein neuer Unternehmensstandort auf dem eBay Campus in Berlin Dreilinden erffnet, um die enge operative Zusammenarbeit mit PayPal weiter zu intensivieren. Seit Dezember 2011 ist die BillSAFE GmbH ein 100%iges PayPal Unternehmen und Teil der eBay Firmengruppe. Die von BillSAFE angebotenen Produkte bndeln die Erfahrung aus der Abwicklung von mehreren hundert Millionen E-Commerce Transaktionen durch PayPal mit der Expertise in der Bearbeitung von mehreren Millionen Inkassofllen durch die mediafinanz AG. (Copy of the Vendor Homepage: http://www.billsafe.de/company/about ) Abstract Advisory Information: ============================== The Vulnerability Laboratory Research Team discovered a POST inject web vulnerability in the official Paypal Inc Billsafe online payment service web-application. Vulnerability Disclosure Timeline: ================================== 2012-12-27: Researcher Notification & Coordination (Benjamin Kunz Mejri) 2013-12-28: Vendor Notification (PayPal Site Security Team - Bug Bounty Program) 2013-01-04: Vendor Response/Feedback (PayPal Site Security Team - Bug Bounty Program) 2013-11-15: Vendor Fix/Patch (PayPal Developer Team - Bug Bounty Reward) 2013-11-16: Public Disclosure (Vulnerability Laboratory) Discovery Status: ================= Published Affected Product(s): ==================== PayPal Inc Product: BillSafe - Online Payment Service 2012 Q4 Exploitation Technique: ======================= Remote Severity Level: =============== Medium Technical Details & Description: ================================ A remote POST inject web vulnerability has been discovered in the official Paypal Inc Billsafe online payment service web-application. The issue allows remote attackers to inject via POST method request own malicious persistent script codes to compromise the application. The vulnerability is located in the integration center module. Remote attackers can manipulate the POST method request of the vulnerable `Register to download formular`. The vulnerable application values are company (firma), `firstname (vorname), `lastname (nachname)` and `shop-url`. The server accepts the manipulated POST context and saves all details as html in the application dbms for future usage. The security risk of the POST inject web vulnerability with persistent attack vector is estimated medium with a cvss (common vulnerability scoring system) count of 3.5(+). The input does not validate the saved context and the input fields are not restricted to prevent future executions. Whenever an attacker is processing to include malicious context the request via POST method will be accepted by the server without secure encoding procedure. Exploitation of the POST inject web vulnerability requires no privileged web application user account and low or medium user interaction. Successful exploitation of the client-side cross site scripting web vulnerabilities results in session hijacking, client-side phishing, client-side unauthorized/open (external) redirects and client-side manipulation of the exception module context. Vulnerable Service(s): [+] Paypal - BillSafe Vulnerable Section(s): [+] Integration Center (Integrations Center) Vulnerable Module(s): [+] Register to download Formular (Registration zum Formular download) Vulnerable Parameter(s): [+] Firma (company) [+] Vorname (firstname) [+] Nachname (lastname) [+] Shop-URL Proof of Concept (PoC): ======================= The post inject web vulnerability can be exploited by remote attackers without privileged application user account and with low or medium user interaction. For security demonstration or to reproduce the vulnerability follow the information below ... --- PoC Session Request Logs [POST] --- Host=www.billsafe.de User-Agent=Mozilla/5.0 (Windows NT 6.1; WOW64; rv:17.0) Gecko/20100101 Firefox/17.0 Accept=text/html, */*; q=0.01 Accept-Language=de-de,de;q=0.8,en-us;q=0.5,en;q=0.3 Accept-Encoding=gzip, deflate DNT=1 Connection=keep-alive Content-Type=application/x-www-form-urlencoded; charset=UTF-8 X-Requested-With=XMLHttpRequest Referer=http://www.billsafe.de/integration-center/shop-systems Content-Length=427 Cookie=__utma=22145316.759281629.1356643963.1356643963.1356643963.1; __utmb=22145316.25.9.1356643975887; __utmc=22145316; __utmz=22145316.1356643963.1.1.utmcsr=google|utmccn=(organic)|utmcmd=organic|utmctr=billsafe%20paypal; PHPSESSID=2qhldnsb86c71flbko91cofc85 Pragma=no-cache Cache-Control=no-cache POSTDATA= company=%3E%22+'[INJECTED SCRIPT CODE!])+%3C&firstname=%3E%22+'[INJECTED SCRIPT CODE!])+%3C&lastname=%3E%22+'[INJECTED SCRIPT CODE!]) +%3C&email=admin%40vulnerability-lab.com&shopUrl=http%3A%2F%2Fwww.%3E%22+'[INJECTED SCRIPT CODE!])+%3C.de +&terms=1&version=1337(6)&system=4&validate=true&format=html --- Response Header [200] --- Status=OK - 200 Date=Thu, 27 Dec 2012 21:47:11 GMT Server=Apache Cache-Control=max-age=2592000 Expires=Sat, 26 Jan 2013 21:47:11 GMT Vary=Accept-Encoding Content-Encoding=gzip Content-Length=511 Keep-Alive=timeout=15, max=68 Connection=Keep-Alive Content-Type=text/html Reference(s): http://www.billsafe.de/integration-center/shop-systems > [Download] http://www.billsafe.de/integration-center/api-sdk > [Download] Solution - Fix & Patch: ======================= The vulnerability can be patched by a secure parse of the vulnerable values in the POST method request. Also encode and parse the output of the vulnerable values even if the input has already been encoded and restricted. Security Risk: ============== The security risk of the POST inject web vulnerability in the register to download formular module is estimated as medium. Credits & Authors: ================== Vulnerability Laboratory [Research Team] - Benjamin Kunz Mejri (bkm@vulnerability-lab.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. 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