Post Syndicated from Bruce Schneier original https://www.schneier.com/blog/archives/2020/12/hiding-malware-in-social-media-buttons.html
Clever tactic:
This new malware was discovered by researchers at Dutch cyber-security company Sansec that focuses on defending e-commerce websites from digital skimming (also known as Magecart) attacks.
The payment skimmer malware pulls its sleight of hand trick with the help of a double payload structure where the source code of the skimmer script that steals customers’ credit cards will be concealed in a social sharing icon loaded as an HTML ‘svg’ element with a ‘path’ element as a container.
The syntax for hiding the skimmer’s source code as a social media button perfectly mimics an ‘svg’ element named using social media platform names (e.g., facebook_full, twitter_full, instagram_full, youtube_full, pinterest_full, and google_full).
A separate decoder deployed separately somewhere on the e-commerce site’s server is used to extract and execute the code of the hidden credit card stealer.
This tactic increases the chances of avoiding detection even if one of the two malware components is found since the malware loader is not necessarily stored within the same location as the skimmer payload and their true purpose might evade superficial analysis.