"Because this is an ongoing investigation, we cannot disclose specific details regarding the incident or comment, other than to say that we are cooperating and we have notified the banks that issue MasterCard cards to monitor for any suspicious account activity and take the necessary steps to protect cardholders," read a MasterCard statement issued today.
According to a silicon.com report, a security breach occurred at a U.K. online retailer, leading to thousands of MasterCard and Visa holders to cancel their credit cards. As many as 4,000 U.K. MasterCard customers were affected, the report said.
Visa Europe released a statement on Friday saying: "Visa Europe can confirm that it is aware of a suspected data compromise involving a U.K.-based online merchant. A full investigation is continuing and Visa is working closely with all appropriate organizations to resolve this issue as a matter of urgency. In the event that a cardholder's account has been compromised, Visa would like to reassure the cardholder that they are fully protected and will not be liable for any loss."
A MasterCard spokesman would not comment on that.
"MasterCard International is concerned whenever cardholders are inconvenienced, and we will continue to monitor this event," the company statement said. "As usual, if a MasterCard cardholder is concerned about his or her individual account, they should contact their issuing financial institution."
Representatives of Manhattan-based security vendor CounterStorm – which produces an internal network defense appliance – said they were not surprised by the news.
Hackers more and more are launching targeted, financially driven attacks designed to steal confidential information at companies that have security holes, said company officials.
"Traditional security does not stand up against the most forceful of attackers," said Matt Miller, CounterStorm vice president of engineering. "Hackers know what security is in place. There's a lot of reconnaissance going on."