Favicons Found Housing Credit Card Skimming Malware

Malicious actors set up an entire online repository of malicious, credit card skimmer-laden favicons to lure in companies looking for a graphic to appear their browser tab.

Favicons are a branding graphic, also known as a shortcut icon, website icon, tab icon, URL icon or bookmark icon. And while they are normally benign, a cybergang managed to build a rather elaborate scheme that utilized them to skim credit card information, reported Malwarebytes’ Senior Analyst Jerome Segura.

The threat actors created the site myicons[.]net and loaded it with the graphics. The site was registered about one week ago and is hosted on a server known for its malicious activities. To top it off the graphics themselves had been stolen from another site.

At first Segura was under the impression the operators were using steganography to hide the skimmer in the image.

“But this was not the case. The image was properly formatted, with no extra code inside,” Segura said, adding the next step was to see how it behaved in action. “Lo and behold, when visiting the checkout page of a compromised Magento website, the innocent favicon.png turned into something else altogether. Instead of serving a PNG image, the malicious server returns JavaScript code that consists of a credit card payment form.”

This form is loaded dynamically in the DOM to override the correct form. The skimmer itself has been nicknamed Ant and Cockroach and is designed for use against those speaking English and Portuguese.

In addition to the payment card data, the skimmer also retrieves the victims name, address, phone number and email.