On a muggy spring night five years ago in the southern Chinese city of Shenzhen, six young men were slowly getting drunk. “We’d all had a few beers when someone first mentioned Foxconn,” one of them recalls. “But we immediately saw that it was a great idea.”

The plan was to hack into the computer systems of the giant Taiwanese contract manufacturer, which assembles many of the world’s best-selling electronic gadgets, such as Apple’s iPhones. This was no drunken whim. Four months later, the six hackers had breached Foxconn’s email system, according to three people with knowledge of the operation.

Foxconn’s position at the heart of the global technology value chain made it an alluring target for potential blackmailers. The company’s 1.4m workers assemble products for the cream of the global technology industry including HP, Dell, Cisco, Acer, IBM, Microsoft and Sony.