Nicholas Burns’ emails reportedly accessed in hack that exploited flaw in Microsoft system and took Washington by surprise

The US ambassador to Beijing, Nicholas Burns, was reportedly one of the American officials whose emails were accessed in a recent Chinese hacking attack which took Washington by surprise with its sophistication.

Another target was Daniel Kritenbrink, the assistant secretary of state for east Asia, the Wall Street Journal reported on Thursday. When the attack was first disclosed last week, the administration admitted the email account of the commerce secretary, Gina Raimondo, had also been compromised. US officials were quoted as saying those were the three most senior targets but that in total, hundreds of thousands of government email accounts could have been breached.