The number of companies and organizations compromised by a security vulnerability in Microsoft Corp.’s SharePoint servers is increasing rapidly, with the tally of victims soaring more than six-fold in a few days,

The Department of Energy, which oversees the agency that manages the US nuclear weapons stockpile, confirms it was affected by the SharePoint bug, but says it was 'minimally impacted.'

Victims of the recent global hacking campaign include the National Institutes of Health and the National Nuclear Security Administration, officials said.