The company said it is investigating with the help of inside and outside cybersecurity experts, and has not determined yet if the data came from AT&T or one of its vendors.
“Currently, AT&T does not have evidence of unauthorized access to its systems resulting in exfiltration of the data set,” the company said in a statement.
The data appears to be from 2019 or earlier, and contains information from 7.6 million current AT&T account holders and about 65.4 million former account holders, AT&T said.
The company said it was notifying customers whose data was leaked and would pay for credit monitoring when applicable.
Many high-profile companies have suffered data breaches, including both of AT&T’s biggest rivals. Verizon has seen multiple reports of information leaks over the years, and T-Mobile has had at least eight incidents since 2018, including a 2021 instance in which hackers stole the data of millions of customers. This year, a hack at a third-party company may have exposed the account information of American Express cardholders.
AT&T was thrust into a harsh spotlight last month when a massive cellphone outage affected more than 1.7 million customers and disrupted 911 services in some states. The company said it was caused by a technical error, not a cyberattack.
