Credit card skimmer masquerades as favicon

Credit card skimmer masquerades as favicon

Malware authors are notorious for their deceptive attempts at staying one step ahead of defenders. As their schemes get exposed, they always need to go back to their bag of tricks to pull out a new one.

When it comes to online credit card skimmers, we have already seen a number of evasion techniques, some fairly simple and others more elaborate. The goal remains to deceive online shoppers while staying under the radar from website administrators and security scanners.

In this latest instance, we observed an old server-side trick combined with the clever use of an icon file to hide a web skimmer. Threat actors registered a new website purporting to offer thousands of images and icons for download, but which in reality has a single purpose: to act as a façade for a credit card skimming operation.

The suspicious favicon

This latest case started with an image file displayed on the browser’s tab often used for branding or identifying a website, also known as a favicon.

While reviewing our crawler logs, we noticed requests to a domain called myicons[.]net hosting various icons and, in particular, favicons. Several e-commerce sites were loading a Magento favicon from this domain.

This in itself is not particularly suspicious. However, we noticed that the domain myicons[.]net was registered just a few days ago and was hosted on a server (83.166.244[.]76) that was previously identified as malicious. In a blog post, web security company Sucuri disclosed how this host was part of a web skimming campaign using time-based domain names.

In addition, we found that the person who registered myicons[.]net stole all the content from a legitimate site hosted at; and they did it in the most simple way—by loading it as an iframe: