AT&T sues over unauthorized access to data

On Wednesday, the company's services division filed a lawsuit in U.S district court in San Antonio, Texas, to block 25 unnamed "John Doe" defendants who have allegedly pretended to be customers to gain access to account information.

AT&T customers affected by the data breach have been notified and access to their online accounts has been frozen, the company said.

"Regrettably, there are always people looking for ways to circumvent the system," Priscilla Hill-Ardoin, chief privacy officer for AT&T, said in a statement. "But we intend to remain vigilant in order to keep our customers' information secure."