The company said the attacks had been described by another security outfit known as Sansec and that all the sites were running Magento 1, a version of software that is used to set up e-commerce websites.

The name Ant and Cockroach was given to the skimmer because it features the words “ant” and “cockroach” as part of its function names sprinkled throughout the skimming code.

Various Magecart groups have been named as being behind attacks on websites like those of British Airways, online retailer Newegg, customer rating plugin Shopper Approved, Forbes magazine and Indian outsourcing firm Wipro.

"The recent wave of attacks on Magento 1 sites and subsequent skimmer injections is connected to long-running activity, including other skimming campaigns and other malicious injections, such as coin miners and malvertising," Herman said.

"The skimming activity has been various and has evolved, using different skimmers and different skimmer variants. In all instances, we have observed the use of loader scripts that, in most cases, run checks against the URL looking for checkout pages."

He said a web of infrastructure connections, along with the techniques RiskIQ and others had documented starting in January 2019 — but also tied to activity since at least 2016 — pointed to one group, which RiskIQ tracked as Magecart Group 12.

"This group has carried out a large number of diverse Magecart attacks that often compromise large numbers of websites at once through supply chain attacks, such as the Adverline incident, or through the use of exploits such as in the September Magento 1 compromises," Herman said.

"Since August 2019, the skimmer most often used by this group has been the Ant and Cockroach skimmer. We have observed this skimmer using different forms of obfuscation, such as the distinctive 'radix' obfuscation. The recent wave of attacks uses a loader that runs checks against the URL and ensures that developer tools are not in use before loading the skimmer.

"This loader has been observed obfuscated and not obfuscated. The skimmer is the Ant and Cockroach skimmer, obfuscated with simple encoding, rather than the more complicated and recognisable 'radix' obfuscation. RiskIQ data allows us to easily connect this campaign to past activity and OSINT sources, putting the recent activity in context and creating a complete picture of the actors behind it."

The security brief can be downloaded here.