Sanguine Security analysts have discovered that attackers are using steganography and hiding MageCart skimmers in buttons designed to publish content on social networks.
Steganography means hiding information within another format (for example, text within images, images within videos, and so on). In recent years, the most common form of steganographic attacks has been hiding malicious payloads within image files, usually in PNG or JPG formats. Operators of web skimmers also did not stay away from this trend and hid their malicious code in website logos, product images or in the favicon of infected resources.
Sanguine Security experts now write that SVG files, rather than PNG or JPG files, are used in new attacks to conceal malicious code. Most likely, this is due to the fact that recently, protective solutions have become better at detecting skimmers in ordinary pictures.
In theory, it should be easier to detect malicious code in vector images. However, the researchers write that attackers are smart and designed their payload with these nuances in mind.
“The malicious payload takes the form of an HTML <svg> element using the <path> element as a container for the payload. The payload itself is hidden using syntax that resembles the correct use of the <svg> element, ”reads the expert report.
According to experts, hackers tested this technique back in June, and it was discovered on active e-commerce sites in September, with malicious payloads hidden inside buttons designed to publish content on social networks (Google, Facebook, Twitter, Instagram, YouTube, etc. Pinterest).
In infected stores, as soon as users navigated to the checkout page, a secondary component (called a decoder) read the malicious code hidden inside social media icons and then downloaded a keylogger that would capture and steal bank card information from the checkout form.