Microsoft has warned its customers against a new sophisticated nation-state cyber attack that has its origin in China and is primarily targeting on-premises 'Exchange Server' software of the tech giant. Called "Hafnium," it operates from China and is attacking infectious disease researchers, law firms, higher education institutions, defence contractors, policy think tanks and NGOs in the US for the purpose of exfiltrating information.

"While Hafnium is based in China, it conducts its operations primarily from leased virtual private servers (VPS) in the US," said Tom Burt, Corporate Vice President, Customer Security and Trust at Microsoft. The Microsoft Threat Intelligence Center (MSTIC) found that "Hafnium" would first gain access to an Exchange Server either with stolen passwords or by using the previously undiscovered vulnerabilities to disguise itself as someone who should have access.