Cyber security experts in the National Health Service (NHS) worked alongside the National Cyber Security Centre (NCSC), part of the GCHQ spy agency, to patch computer systems after the attack caused widespread problems on Friday, Wallace said.
The ransomware called Wanna Decrypt, also known as WannaCry, encrypts files on the machine, effectively locking them.
More than 200,000 victims in 150 countries have been registered so far, with warnings the impact could spread further on Monday.
After concerns were reported about three hospitals, cyber security analysts said an older virus had been found.
The UK National Health Service was among those hardest hit, with officials estimating that as many as 70,000 different devices may have been impacted – including vital health care equipment like blood-storage refrigerators, MRI scanners, and critical computer systems.
But speaking publicly for the first time since the cyberattack, Health Secretary Jeremy Hunt said that “according to the latest intelligence we have not seen a second wave of attacks”.
Wainwright told ITV that the world faced an escalating threat, and there was concern about the level of potential attacks on Monday morning.
Microsoft released fixes for the vulnerability in March, but computers that didn’t run the update were subject to the ransom attack.
Also hit were Deutsche Bahn, the Russian Central Bank, Russian Railways, Russia’s Interior Ministry, Megafon and Telefónica.
How to prevent a #ransomware attack? Speaking on the BBC’s Andrew Marr Show, Fallon said the Vanguard submarines that carry the deterrent “operate in isolation” when on patrol, implying that they can’t be hacked remotely.
The health service has been rebuked for using the outdated Windows XP operating system to store digital information, despite security updates for the software having been discontinued by Microsoft.
Patients using Princess Royal University Hospital were unaffected by the cyber attack which swept across the NHS last week.
United Lincolnshire Hospitals Trust has said all patients should attend their booked outpatient appointments and operations “as planned tomorrow (Tuesday) after ‘significant progress” has been made in restoring IT systems following Friday’s cyber attack.
“You are dealing with a criminal”, he said.