Pierluigi Paganini May 23, 2022

A security researcher announced the discovery of an unpatched flaw in PayPal that could allow attackers to steal money from users.

TheHackerNews first reported that a security researcher (that goes online with the moniker h4x0r_dz) has discovered an unpatched flaw in PayPal that could allow attackers to trick users into completing transactions controlled by the attackers with a single click.

This kind of attack leverages an invisible overlay page or HTML element displayed on top of the visible page. Upon clicking on the legitimate page, users are in fact clicking the element controlled by the attackers that overlay the legitimate content.

The expert reported the bug to the PayPal bug bounty program seven months, demonstating that attacker can steal users’ money by exploiting Clickjacking,

The researcher discovered the vulnerability on the “www.paypal[.]com/agreements/approve” endpoint, which was designed for Billing Agreement.

The endpoint should accept only billingAgreementToken, but the expert discovered that it is not true.

“I found that we can pass another tokens type, and this leads to stealing money from victim’s PayPal account.” reads the post published by the researcher. “as you can see in the picture, the attacker is able to load a sensitive paypal.com endpoint in an Iframe, and when the attacker clicks on “near to click here” He will buy something.”

The victim should click everywhere on the page, and it will send money to the attacker’s PayPal.

The issue could be also exploited to subscribe services that allow PayPal payments.

“there are online services that let you add balance using Paypal to your account for example steam! . I can use the same exploit and force the user to add money to my account!” reads the post published by the researchers. “or I can exploit this bug and let the victim create/pay Netflix account for me !.”

The experts published a PoC exploit for this issue, that according to the expert has yet to be patched.

At the time of this writing PayPal has yet to award the bug.

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Pierluigi Paganini

(SecurityAffairs – hacking, domain name system)

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