Researchers found five gigabytes of data that had been stolen from foreign ministries and energy companies by hacking their on-premises Microsoft Exchange servers in the Middle East, Asia and Eastern Europe. Microsoft blamed a group of Chinese state-sponsored hackers for the 2021 attack, which infected as many as 60,000 victims with malware. A person familiar with the investigation into the 2021 hack, who wasnt authorized to speak publicly and requested anonymity, made a similar allegation, saying the data theft followed the same methods. Both hacking campaigns underscore how flaws in Microsofts popular email servers act as a skeleton key for hackers to unlock sensitive data from government and private companies.”]
Source: https://fortune.com/2021/08/04/microsoft-exchange-cyber-attack-diplomats-china/