“The United States and international cybersecurity authorities are issuing this joint Cybersecurity Advisory (CSA) to highlight a recently discovered cluster of activity of interest associated with a People’s Republic of China (PRC) state-sponsored cyber actor, also known as Volt Typhoon,” said a statement released by US, Australian, Canadian, New Zealand and UK authorities.

In a separate statement, Microsoft said Volt Typhoon had been active since mid-2021 and had targeted critical infrastructure in Guam, a crucial US military outpost in the Pacific Ocean.

“Microsoft assesses with moderate confidence that this Volt Typhoon campaign is pursuing development of capabilities that could disrupt critical communications infrastructure between the United States and Asia region during future crises,” the statement said.