An unknown threat actor has infected 953 online stores, most of them running Magento, as part of a long-running campaign active since July 2025. According to Dutch e-commerce security company Sansec, the activity is designed to add a small piece of code to the store’s pages that, when visited by unsuspecting users, serves malicious JavaScript loader code through Magento CMS blocks. “When you visit, that code makes your browser ask the group’s server what to do next,” Sansec said. The latest JavaScript loader domain is hosted behind Cloudflare and only responds to script requests from real visitors of infected stores. The loader is staged within Magento’s cms_block database table, which is used to render static content into storefront pages.