The data of nearly all customers of the telecommunications giant AT&T was downloaded to a third-party platform in a 2022 security breach, the company said Friday, as cyberattacks against businesses, schools and health systems continue to spread globally.

The breach hit customers of AT&T’s cellular customers, customers of mobile virtual network operators using AT&T’s wireless network, as well as its landline customers who interacted with those cellular numbers.

AT&T said that it currently doesn’t believe that the data is publicly available.