Background: 'Vaccine' created for huge cyber-attackpublished at 10:24 British Summer Time 28 June 2017
Security researchers have discovered a "vaccine" for the huge cyber-attack that hit organisations across the world on Tuesday.
The creation of a single file can stop the attack from infecting a machine.
However, researchers have not been able to find a so-called kill switch that would prevent the crippling ransomware from spreading to other vulnerable computers.
Experts are still unsure about the attack's origins or its real purpose.