eBay has no plans to fix a "severe" vulnerability that allows attackers to use the company's trusted website to distribute malicious code and phishing pages, researchers from security firm Check Point Software said.
"Customers can be tricked into opening the page, and the code will then be executed by the user's browser or mobile app, leading to multiple ominous scenarios that range from phishing to binary download." The post went on to say that Check Point researchers privately reported the security hole to eBay in mid-December. On January 16, eBay officials informed Check Point that they had no plans to issue a fix. The post didn't explain the reason behind eBay's decision.
In an e-mail sent to Ars after this post went live, eBay officials wrote: "eBay is committed to providing a safe and secure marketplace for our millions of customers around the world. We take reported security issues very seriously, and work quickly to evaluate them within the context of our entire security infrastructure. We have not found any fraudulent activity stemming from this incident.”
The e-mail added: Also, it's important to understand that we have been in touch with the researcher and have implemented various security filters based on his findings to detect this exploit. Since we allow active content on our site it's important to understand that malicious content on our marketplace is extraordinarily uncommon, which we estimate to be less than two listings per million that use active content on the eBay marketplace.
As the proof-of-concept exploit in the video above demonstrates, exploits require some element of social engineering, mostly in the form of a dialog box that instructs a user to OK the installation of a malicious app. Given the lack of security awareness of many of eBay's hundreds of millions of users and the site's walled-garden environment that aims to block malicious content, it's a fair bet that a significant number of people exposed to the threat would be tricked into infecting their devices or turning over their login credentials.
eBay performs simple verification but only strips alpha-numeric characters from inside the script tags. The JSF**k technique allows the attackers to get around this protection by using a very limited and reduced number of characters.
This is how a simple JSF**k script looks:
This is how a successful exploitation of the vulnerability would look:
As shown, the message which appears on eBay’s website application (specifically, on the attacker’s store on the eBay site) entices the unsuspecting user into downloading a new eBay mobile application by offering a one-time discount.
For example, if a user taps the `download` button, he will unknowingly download a malicious application to his mobile device.