Security researchers say Microsoft customers should take immediate action to defend against the ongoing cyberattacks, and must assume they have already been compromised.

Security experts at Google and Microsoft have discovered that Chinese government-backed hackers are exploiting a serious flaw, known as a zero-day vulnerability, in Microsoft SharePoint, a tool used by many companies to store and share documents internally.

Hours after Microsoft revealed hacking groups affiliated with the Chinese government have been exploiting a flaw in its SharePoint software, Bloomberg News reports that the National Nuclear Security Administration has also been breached in the attacks.

A series of cyberattacks targeting Microsoft collaboration software, specifically SharePoint, have been linked to Chinese hackers and threat actors.

More than 400 systems have been compromised so far in the widespread cyberattacks exploiting vulnerabilities in Microsoft SharePoint servers, according to researchers at Eye Security.

State CISOs in North Carolina and Arizona said their teams began work immediately to ensure on-prem SharePoint systems were secure, following the recent disclosure of an active zero-day exploit.

Microsoft is once again in the cybersecurity spotlight, acknowledging Tuesday morning that hackers linked to China are among those exploiting vulnerabilities in on-premises SharePoint software, the latest in a string… Read More

More details emerged on the ToolShell zero-day attacks targeting SharePoint servers, but confusion remains over the vulnerabilities.