An “accidental hero” has halted the global spread of the WannaCry ransomware, reportedly by spending a few dollars on registering a domain name hidden in the malware.
However, a UK cybersecurity researcher tweeting as @malwaretechblog, with the help of Darien Huss from security firm Proofpoint, found and activated a “kill switch” in the malicious software.
The switch was hardcoded into the malware in case the creator wanted to stop it spreading. This involved a very long nonsensical domain name that the malware makes a request to – just as if it was looking up any website – and if the request comes back and shows that the domain is live, the kill switch takes effect and the malware stops spreading.
“I saw it wasn’t registered and thought, ‘I think I’ll have that’,” he is reported as saying. The purchase cost him $10.69. Immediately, the domain name was registering thousands of connections every second.
The kill switch won’t help anyone whose computer is already infected with the ransomware, and and it’s possible that there are other variants of the malware with different kill switches that will continue to spread.