Hackers injected the Forbes’ subscription website with a Magecart script which collects payment card data customers introduce on the checkout page and exfiltrates it to a server controlled by the attackers. Magecart groups have been active since at least 2015 and represent an ever-evolving threat capable of launching attacks against high profile international companies like Ticketmaster, British Airways, OXO, and Newegg. Group-IB found 2,440 compromised websites during early April which had been infected with payment card skimming scripts.
Source: https://www.bleepingcomputer.com/news/security/hackers-inject-magecart-card-skimmer-in-forbes-subscription-site/