CNN BUSINESS | Here’s what we know so far about the massive Microsoft Exchange hack

New York (CNN Business) – Many security experts remain alarmed about the large, Chinese-linked hack of Microsoft’s Exchange email service a week after the attack was first reported.

The breach is believed to have targeted hundreds of thousands of Exchange users around the world. Microsoft (MSFT) said four vulnerabilities in its software allowed hackers to access servers for the popular email and calendar service, andthe company urged customers to immediately update their on-premises systems with software fixes.

Even the White House quickly got involved, and now multiple US government agencies also are investigating the attack.  —read more—