The US agency responsible for maintaining and designing the nation’s cache of nuclear weapons was among those breached by a hack of Microsoft Corp.’s SharePoint document management software, according to a person with knowledge of the matter.

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.

In a major security lapse, the United States nuclear weapons agency, National Nuclear Security Administration , was breached by a hack of Microsoft SharePoint document management software.As