Microsoft hack: 3,000 UK email servers remain unsecured

More than 3,000 UK email servers remain at risk from the global Microsoft Exchange email flaw, officials believe.The National Cyber Security Centre said it estimated 7,000 servers had been affected by the flaw in the UK and only half had been secured.It said malicious software had been detected on 2,300 machines but it had helped businesses remove it.The agency said it was "vital" that all affected businesses took action to secure their email servers.The announcement reveals the scale of the problem among UK companies for the first time since the global security flaw emerged last week.Ransomware groups have begun using the flaw to install their malicious programs, the NCSC warned - though there was no evidence of widespread ransomware attacks on UK companies so far.Once installed, ransomware locks away a user's data behind strong encryption, making the computer system unusable. The group then demands payment to unlock it - and if demands are not met, will steal or delete the data.