Threat actors have been found exploiting a critical flaw in Magento to inject a persistent backdoor into e-commerce websites.

The attack leverages CVE-2024-20720 (CVSS score: 9.1), which has been described by Adobe as a case of "improper neutralization of special elements" that could pave the way for arbitrary code execution.

It was addressed by the company as part of security updates released on February 13, 2024.

Sansec said it discovered a "cleverly crafted layout template in the database" that's being used to automatically inject malicious code to execute arbitrary commands.

"Attackers combine the Magento layout parser with the beberlei/assert package (installed by default) to execute system commands," the company said.

"Because the layout block is tied to the checkout cart, this command is executed whenever <store>/checkout/cart is requested."

The command in question is sed, which is used to insert a code execution backdoor that's then responsible for delivering a Stripe payment skimmer to capture and exfiltrate financial information to another compromised Magento store.

The development comes as the Russian government has charged six people for using skimmer malware to steal credit card and payment information from foreign e-commerce stores at least since late 2017.

The suspects are Denis Priymachenko, Alexander Aseyev, Alexander Basov, Dmitry Kolpakov, Vladislav Patyuk, and Anton Tolmachev. Recorded Future News reported that the arrests were made a year ago, citing court documents.

"As a result, members of the hacker group illegally took possession of information about almost 160 thousand payment cards of foreign citizens, after which they sold them through shadow internet sites," the Prosecutor General's Office of the Russian Federation said.