LONDON, July 21 (Reuters) - Britain's National Cyber

Security Centre (NCSC) said on Monday it had detected a "limited

number" of UK-based victims in an ongoing hacking campaign that

has affected servers using Microsoft's ( MSFT ) SharePoint

system.

Microsoft ( MSFT ) on Saturday issued an alert about "active attacks"

on SharePoint servers used within organisations. It said that

SharePoint Online in Microsoft ( MSFT ) 365, which is in the cloud, was

not hit by the exploit, also known as a "zero day".