Dallas-based AT&T on Friday revealed that the personal information of some cell phone customers was stolen in April.
The company did not say how many customers were affected.
“We recently learned that three employees of one of our vendors accessed some AT&T customer accounts without proper authorization,” the company said in a statement. “This is completely counter to the way we require our vendors to conduct business.”
AT&T said the information, which included personal information such as social security numbers, was taken from April 9 to April 21 and was used to unlock cell phones.
It does not appear the information was used to access bank or credit card accounts.
“We know our customers count on us and those who support our business to act with integrity and trust, and we take that very seriously,” the company said. “We have taken steps to help prevent this from happening again, notified affected customers, and reported this matter to law enforcement.”
AT&T first reported the breach to regulators in California, which has strict rules about revealing such information.