AT&T revealed Friday that a cyberattack breached the data of “nearly all” of its cellular customers and downloaded it to a third-party cloud platform.The telecom giant has “taken steps” to close off the illegal access point and is working with law enforcement to track down the hackers. At least one person has already been apprehended, AT&T said. “At this time, we do not believe that the data is publicly available,” AT&T said in a statement.The company first learned in April that a cyberattack breached the d ...