In a blog post Tuesday, Microsoft said it observed hackers attempting to “gain initial access to target organizations.” According to Microsoft, those involved included hacking groups called Linen Typhoon and Violet Typhoon—which Microsoft said are linked to the Chinese government—and China-based group Storm-2603.

Microsoft has issued an emergency fix to close off a vulnerability in Microsoft’s widely-used SharePoint software that hackers have exploited to carry out widespread attacks on businesses and at leas...

Bloomberg reported that no sensitive or classified information is known to have been compromised in the attack on the National Nuclear Security Administration, the agency responsible for maintaining ...