Microsoft Corp. and U.S. government officials are still working to understand how a network of suspected Chinese hacking groups carried out an unusually indiscriminate and far-reaching cyberattack on Microsoft email software, more than a month after the discovery of an operation that rendered hundreds of thousands of small businesses, schools and other organizations vulnerable to intrusion. A leading theory has emerged in recent weeks, according to people familiar with the matter: The suspected Chinese hackers mined troves of personal information acquired beforehand to carry out the attack.
Read the article: The Wall Street Journal
