• Anthem

Anthem (Photo : Reuters)

China is now the leading suspect in a "very sophisticated external cyber attack" on U.S. health insurance giant Anthem, Inc. that stole over 80 million records containing personal information from its servers.

Stolen were Social Security numbers, email addresses, employment information, income levels and other personal information of Anthem members in the United States, according to Computer World. Cyber security experts fear the stolen data will be used for identity theft.

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Anthem, however, claims credit card numbers and medical information weren't affected. It set up a special web page addressing the breach and said it was assessing the impact of the attack.

State sponsored hackers working for the Chinese government are the prime suspects in the attack, according to information from the FBI and private cybersecurity firm, Mandiant.

Investigation so far shows that some of the software and techniques used in the attack have strong similarities to those employed almost exclusively in the past by China, said Bloomberg

Anthem's breach might be one of the largest suffered by a health care provider. Anthem has 37.5 million subscribers for its health plans, and 68 million people customers.

The affected Anthem brands were Anthem Blue Cross; Anthem Blue Cross and Blue Shield; Blue Cross and Blue Shield of Georgia; Empire Blue Cross and Blue Shield; Amerigroup; Caremore; Unicare; Healthlink or DeCare, The Register reported.

Anthem CEO Joseph Swedish described the breach as a "very sophisticated external cyber attack." He said his own information was stolen, as well.

"We join you in your concern and frustration, and I assure you that we are working around the clock to do everything we can to further secure your data," Swedish said.

Anthem hired Mandiant, a computer forensics unit, to investigate the breach.