Hacker steals private data of Apple iCloud users: Report

Authorities in the US have arrested a man for hacking into the accounts of Apple iCloud users and stealing their intimate photos and videos, as per a report by TechRadar. As per the court filings, Hao Kuo Chi, a resident of California, was found to have conspired with others to access the private accounts of more than three hundred Apple customers in the US, with the campaign extending at least as far back as September 2014.
As per a document from the US Department of Justice, Chi “specifically sought out nude photographs and videos of young women” once he broke into the accounts. He then traded these with other “conspirators”, some of whom later leaked the pictures and video into the public domain.
How did he break into the secure Apple iCloud?