Data of nearly all AT&T customers leaked from 3rd-party platform

The AT&T logo is positioned above one of its retail stores in New York, U.S. October 24, 2016. /AP

The data of nearly all customers of U.S. telecommunications giant AT&T was downloaded from a third-party platform in a security breach, the company said Friday.

The breach, which took place in April of this year, hit AT&T's cellular customers and customers of mobile virtual network o