On March 2, 2021, Microsoft announced that the company was facing a state-sponsored cybersecurity threat that they dubbed “Hafnium,” which was based out of China. Hafnium’s attacks targeted a company product called Microsoft Exchange Server, an email and calendar server product used by tens of thousands of customers. Microsoft released a series of patches for Microsoft Exchange Server. However, there was a major problem. If users incorrectly installed the patch, the patch did not fully update the correct files. Most worrisome, if that happened the user received no warning message that the patch wasn't installed. Industry experts describe the Hafnium attacks as "astronomical" and "crazy huge" in their scope. Bloomberg reported that there are “at least 60,000 known victims globally.” In July 2021, the U.S. government and Western allies formally blamed China for the attack. The announcement was not accompanied by sanctions against the Chinese government. The U.S. Justice Department filed charges against four Chinese nationals who prosecutors said who were working with China's Ministry of State Security in the cyberattack.