A cyber crime syndicate known as Magecart, which is made up of dozens of sub-groups that indulge in credit card theft by skimming online payment forms, has been found to be implicated in more than two million such attacks.

Sites that have been decommissioned due to attacks by the card-skimming attack group Magecart are being hijacked and re-used for other malicious activity once they come back online by a secondary group of cyber criminals, the security firm RiskIQ claims.

The subscription site for Forbes magazine has been the victim of the card-skimming attack group Magecart, with the well-known website leaking card data on Wednesday until the attack was noticed and the site taken down.