Data Processors International, based in Omaha, said Wednesday that "an unauthorized outside party" had tapped into its computer system, prompting a criminal investigation.
Scott Jones, a company spokesman, refused to comment on when the cracker gained access and how many credit card account numbers may have been compromised.
Credit card companies and the Secret Service have said that as many as 8 million account numbers were accessed. The card companies said they were notified of the incident early this month.
When the security breach was detected, Data Processors immediately notified credit card companies and law enforcement agencies, Jones said. He added that the company is sharing all its information with the Secret Service and the FBI.
Credit card companies said they had received no reports of fraudulent activity involving the accounts as of late Wednesday. The companies, including Visa, MasterCard, American Express and Discover, have policies in place that protect consumers from liability for fraudulent use of their accounts.
At least one bank -- Citizens Financial Group of Providence, R.I., which is owned by the Royal Bank of Scotland -- canceled 8,800 cards and issued replacements after being notified of the security breach.
Data Processors International, which has 40 employees, takes up half the first floor of a three-story building. The company's clients include mail-order and marketing businesses that run TV ads asking viewers to order products over the phone.
Jones would not name any of the clients.
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