Document Title: =============== Paypal Bug Bounty #48 - Persistent Web Vulnerability References (Source): ==================== http://www.vulnerability-lab.com/get_content.php?id=830 PayPal Security UID: dyf1f8cejz Release Date: ============= 2013-03-28 Vulnerability Laboratory ID (VL-ID): ==================================== 830 Common Vulnerability Scoring System: ==================================== 3.5 Product & Service Introduction: =============================== PayPal offers, both companies and individuals, a simple, quick and innovative solution of receiving money and making payments online. In ten years time, this company has become an authority in this market. Online buyers, eBay vendors, online stores and even the traditional offline companies. The number of users who trust PayPal with their transactions, continues to grow. 175 million PayPal accounts worldwide are certainly proof of that. PayPal uses a unique and extremely advanced system to prevent fraud, which guarantees a completely reliable and safe solution for real time payments online. GP+ objectively analyzes and assesses the quality and find ablility of online stores and, at the same time, examines the possibilities to avoid attrition in the sales process. The base of this analysis is formed by: Google, Yahoo! and Microsoft Live, the W3C, Lipperhey in house research, governments, renowned trade publications, worldwide specialists pool and research done by PayPal into the characteristics of the most successful online stores worldwide. (Copy of the Vendor Homepage: https://www.paypal-gpplus.com/en/about/ ) Abstract Advisory Information: ============================== The Vulnerability Laboratory Research Team discovered a input validation web vulnerability in the official PayPal GP+ Web Application Service. Vulnerability Disclosure Timeline: ================================== 2013-01-02: Researcher Notification & Coordination 2013-01-04: Vendor Notification 2013-01-16: Vendor Response/Feedback 2013-03-26: Vendor Fix/Patch 2013-03-29: Public Disclosure Discovery Status: ================= Published Affected Product(s): ==================== Exploitation Technique: ======================= Remote Severity Level: =============== Low Technical Details & Description: ================================ A persistent input validation web vulnerability is detected in the official Paypal GP+ service application for anlayzing websites. The vulnerability typus allows an attacker to inject own malicious script code in the vulnerable module on application-side (persistent). The vulnerability is located in the `Indexability` section of the `Expert view` modules of the website, that has been analyzed. The malicious code can be inserted in the `robots.txt` file of the website that will be analyzed. After the search is done, the malicious script code will be executed in the Robots.txt section in Home > Dashboard Analyses > Expert View > Indexability when processing to load the robots function exception-handling with the bound error listing. Exploitation of the vulnerability requires low user interaction without privileged web application user account. Successful exploitation of the vulnerability result in persistent session hijacking, persistent phishing, persistent external redirects, persistent external malware loads via inject and persistent vulnerable module web context manipulation. Vulnerable Section(s): [+] Paypal GP+ - (https://www.paypal-gpplus.com/en/dashboard/all/) Vulnerable Module(s): [+] Expert View => Indexability Vulnerable Parameter(s): [+] Robots.txt Affected Module(s): [+] Expert View => Indexability - Exception Handling (Listing) Proof of Concept (PoC): ======================= The vulnerability can be exploited by remote attackers without user interaction and without privileged application user account. For demonstration or reproduce ... A remote attacker can insert the malicious script code in the "robots.txt" of the website he would like to request. After the scan is done, the victim user goes to "Expert view" and choose Indexability, the malicious code will get executed in the Robots.txt section. URL: https://www.paypal-gpplus.com/en/dashboard/analysis/2728779/indexability/ Code Review: Indexability [Robots.txt] Robots.txt Your robots.txt file contains 3 disallows for user agents: Solution - Fix & Patch: ======================= 2013-03-26: Vendor Fix/Patch Security Risk: ============== The security risk of the persistent input validation vulnerabilities are estimated as medium(+). Credits & Authors: ================== Vulnerability Laboratory [Research Team] - Ibrahim El-Sayed (the_storm) [storm@vulnerability-lab.com] [iel-sayed.blogspot.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.vulnerability-lab.com/register Contact: admin@vulnerability-lab.com - support@vulnerability-lab.com - research@vulnerability-lab.com Section: video.vulnerability-lab.com - forum.vulnerability-lab.com - news.vulnerability-lab.com 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 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, sourcecode, 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 support@vulnerability-lab.com) to get a permission. Copyright © 2013 | Vulnerability Laboratory