Microsoft issued an emergency fix to close off a vulnerability in its SharePoint software that hackers have exploited to carry out widespread attacks on businesses and at least some federal agencies.

Microsoft has warned that Chinese state-sponsored hackers are among those exploiting flaws in its SharePoint software.

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.

Researchers first uncovered a sweeping cyber espionage operation targeting Microsoft server software affecting at least 100 organisations.

Microsoft Corp.’s server software is under attack from unidentified hackers, with cybersecurity analysts warning of widespread security breaches across the globe.The Redmond, Washington-based software maker said it had released a new security patch for customers to apply to their SharePoint servers “to mitigate active attacks targeting on-premises servers,