Since Friday’s breach more than 200,000 victims - including York Teaching Hospital Trust and Hull and East Yorkshire Hospitals NHS Trust - across 150 countries have been infected by the Wanna Decryptor ransomware, also known as WannaCry.
Europol director Rob Wainwright said the attack was indiscriminate across the private and public sectors.
“We are in the face of an escalating threat, the numbers are going up, I am worried about how the numbers will continue to grow when people go to work and turn their machines. The latest count is over 200,000 victims in at least 150 countries. Many of those will be businesses including large corporations.”
Organisations across the globe are now working non-stop to hunt down those responsible for the ransomware.
Meanwhile health authorities are racing to upgrade security software amid fears hackers could exploit the same vulnerability with a new virus.
There have also been calls for an inquiry into the circumstances surrounding the attack and preparedness by the NHS.
Patrick Crowley, chief executive of York Hospitals, said: “Services are running almost normally. Just treat us with a bit of understanding because things are running a little bit slower but if you have an appointment assume it is going to go ahead.”
Just the beginning
The doctor who said hospitals could be vulnerable to ransomware one day before a virus struck the NHS has warned this could “just be the beginning”.
Dr Krishna Chinthapalli said the havoc wreaked on some health services in an international cyber attack could encourage hackers to target hospitals.
He wrote in a British Medical Journal article on Thursday that some hospitals “will almost certainly be shut down by ransomware this year”. The following day dozens of trusts in England and Scotland were forced to cancel procedures after staff reported seeing computers go down “one by one”.
Ransomware encrypts a computer hard drive and then demands an online payment for a key to unlock the data. In many cases, the payment makes no difference and the data remains forever out of reach.
Dr Chinthapalli, a neurology registrar at the National Hospital for Neurology and Neurosurgery in London, said: “Some people have said I predicted this but that’s not quite right, I was warning about this and saying that attacks were likely to be imminent this year.
“These ransomware attacks have been on the rise over the last three years, it wasn’t exactly something that was a shock – what was surprising is the scale of this one.”
He added: “Healthcare remains vulnerable and if anything this one will raise awareness among the hacker community that hospitals are a target for them, this could just be the beginning.
“Hackers will realise that hospitals can be hacked relatively easily, and of course that hospitals have very sensitive data and we need that to manage our patients and it’s time-critical data.”
A British cyber whiz became an “accidental hero” after he registered a domain name that stopped the spread of the malicious software, which exploits a vulnerability in Microsoft Windows software. The anonymous specialist, known only as MalwareTech, prevented more than 100,000 computers across the globe from being infected. However, MalwareTech warned that hackers could upgrade the virus to remove the kill switch.
“Version 1 of WannaCrypt was stoppable but version 2.0 will likely remove the flaw. You’re only safe if you patch ASAP,” he wrote on Twitter.
The attack led to criticism of the Government and NHS bosses, with the Liberal Democrats demanding an inquiry takes place.
Home Secretary Amber Rudd admitted “there’s always more” that can be done to protect against viruses.
She said: “If you look at who’s been impacted by this virus, it’s a huge variety across different industries and across international governments.
“This is a virus that attacked Windows platforms. The fact is the NHS has fallen victim to this.
“I don’t think it’s to do with that preparedness. There’s always more we can all do to make sure we’re secure against viruses, but I think there have already been good preparations in place by the NHS to make sure they were ready for this sort of attack.”
Labour’s Shadow Health Secretary, Jonathan Ashworth, in a letter to Mr Hunt, said concerns were repeatedly flagged about outdated computer systems and the lack of investment in modern computer systems.
He demanded that the Conservatives publish the Department of Health’s risk register to see how seriously they were taking IT threats.
Among those affected by the virus was Nissan UK, but the car manufacturer said there had been no major impact.