Image credits: PayPal.com





Stored XSS Vulnerability.



A critical stored XSS Vulnerability was found in PayPal's secure payment system by Egypt-based researcher Ebrahim Egazy. The persistent (or stored) XSS vulnerability is a more devastating variant of a cross-site scripting flaw. It occurs when the data provided by the attacker is saved by the server, and then permanently displayed on "normal" pages returned to other users in the course of regular browsing, without proper HTML escaping.





About the Vulnerability



The vulnerability was found at the PayPal Secure payment URL https://securepayments.paypal.com/cgi-bin/acquiringweb . Paypal SecurePayments domain is used by PayPal users to do secure payments when purchasing from any shopping site. This secure payments page require Paypal users to fill some forms that include their Credit Card number, CVV2, Expiry date and more to finalize the payment and purchase the products via their PayPal account. In normal cases, the submitted data is processed through encrypted channel(HTTPS) so attackers won’t be able to sniff/steal such data.





The researcher was able to find a stored XSS vulnerability that affects the SecurePayment page directly which allowed him to alter the page HTML and rewrite the page content. This makes it possible for an attacker to provide his own HTML forms to the user and send the users data back to attacker’s server in clear text format. This information can be used to purchase anything on behalf of users or even transfer the user's money to attackers account.









Steps to exploit Stored XSS Vulnerability



The researcher gives a detailed step by step explanation as below, in his blog. According to him the worst attacking scenario that could be conducted using this vulnerability is as below:





An attacker needs to set up a rogue shopping site or hijack any legitimate shopping site Now modify the "Checkout" button with an URL designed to exploit the XSS vulnerability Whenever Paypal users browse the malformed shopping website and click on "CheckOut" button to Pay with their Paypal account, they'll be redirected to the Secure Payments page The page actually displays a phishing page where the victims are asked to enter their payment card information to complete the purchasing. Now on clicking the Submit Payment Button, instead of paying the product price (let's say $100), the Paypal user will pay the attacker amount of attacker's choice.





Vulnerability Is patched now.





Egazy reported the bug to PayPal team on June 19th and it was fixed on August 25. He was also rewarded by PayPal with a bug bounty of $750 as per their bug bounty policies.



Source : http://www.sec-down.com/wordpress/?p=553



Also Read: R.I.P Adobe Flash. It's Time To Move On! reported the bug to PayPal team on June 19th and it was fixed on August 25. He was also rewarded by PayPal with a bug bounty of $750 as per their bug bounty policies.





A critical security vulnerability has been discovered in the eBay-owned PayPal that could allow attackers to steal login credentials and credit card details in plain text.