Microsoft has plugged security holes in its Exchange email software. Hackers who worked from China have exploited it, according to the American software company.
According to Microsoft, the cybercriminals targeted various US agencies, including researchers, lawyers, educational institutions, and NGOs.
They could access email accounts through software flaws, as well as deploy malware.
Microsoft is calling on customers in a blog post to install the latest software patches to close loopholes. The Exchange Server versions 2013, 2016 and 2019 are affected.