Microsoft accuses hackers belonging to the Chinese government-backed cyberespionage group Hafnium of attacks on mail server software.
The tech giant reported in a blog post that a group of hackers had exploited four previously undetected vulnerabilities in different software versions. They allowed cybercriminals to remotely access Microsoft users' mailboxes.
As added, Hafnium's activities target infectious disease researchers, law firms, higher education institutions and defense companies. It also attacks political think tanks and non-governmental groups.
The BBC said it was the eighth time in the past twelve months that Microsoft has publicly accused national government-backed groups of targeting institutions of importance to users. Hafnium is based in China, but mainly operates from leased private servers located in the USA.
While many US tech companies have tumultuous relationships with the Chinese government, Microsoft has maintained its presence in China since 1992 (PAP).