Health insurer Anthem said hackers infiltrated its computer network and accessed a swathe of personal information about current and former customers including their incomes and street addresses.
The company said in a statement Wednesday it is contacting customers affected by the “very sophisticated” cyberattack.
It said credit card information wasn’t compromised and so far it has not found evidence that medical information such as insurance claims and test results was targeted or obtained.
Anthem said the FBI is investigating and it has hired Internet security company Mandiant to improve its network defenses.
Information stolen included names, birth dates, social security numbers, street addresses, email addresses and employment details including income.
The FBI urged Anthem customers contacted by the insurer to report suspected instances of identity theft.
It praised the company’s rapid response to the hack.