Hackers linked to Beijing accessed the email account of US Ambassador to China Nicholas Burns in a spying operation believed to have compromised hundreds of thousands of US government emails, the Wall Street Journal reported.
Daniel Kritenbrink, assistant secretary of state for East Asia, was also hacked in the largest spying operation revealed earlier this month by Microsoft MSFT.O, according to the report on Thursday, citing people familiar with the matter.
Asked about the alleged breach of the accounts of the two diplomats, the State Department declined to provide details, saying its investigation into the spying operation was ongoing.
It added that: “For security reasons, we are not going to share additional information about the nature and scope of this cybersecurity incident at this time.”
Before the WSJ report appeared, Kritenbrink was asked at a congressional session on US policy toward China if he could rule out that his emails or those of his staff were the target of the Microsoft hack.
“I can’t comment on an investigation that the FBI is conducting, but no, I’m not ruling it out,” Kritenbrink said.
Burns and Kritenbrink join US Commerce Secretary Gina Raimondo as the only publicly identified victims of the spy campaign, which prompted a warning from Washington’s top diplomat to his Chinese counterpart.
The Chinese embassy in Washington did not immediately respond to a request for comment on the report, but the Chinese Foreign Ministry previously called the allegations “disinformation.”
Microsoft said last week that Chinese hackers misappropriated one of its digital keys and used a flaw in its code to steal email from US government agencies and other customers.
The company did not immediately respond to a message seeking comment on the WSJ report.
The leak has put Microsoft’s security practices under scrutiny, and officials and lawmakers have called on the company to make its top level of digital auditing, also called a registry, available to all customers free of charge.
Microsoft said late on Thursday that it would take the criticism into account.
Last week, White House National Security Council spokesman Adam Hodge said a breach in Microsoft’s cloud security “affected unclassified systems,” without elaborating.
“Officials immediately contacted Microsoft to find the source and the breach in their cloud service,” Hodge added.
The State Department “detected atypical activity” and “took immediate steps to secure our systems,” a department spokesperson said in a statement at the time.
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