It was a Sunday afternoon in August 2012 and Gert-Jan Schenk, the European head of cyber security giant McAfee, had just arrived home from summer vacation.

As he busied himself with unpacking luggage, Schenk’s mobile phone rang, displaying an unfamiliar number. The father of two had his hands full with bags and kids, so he let it go to voicemail. Then the number rang again, and then a third time, before Schenk finally put his things down and answered the phone.

To Schenk’s surprise, the person on the line was the chief information officer of the world’s biggest oil company. And he sounded worried.

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