Symantec says 'highly likely' North Korea group behind ransomware attacks

A screenshot shows a WannaCry ransomware demand, provided by cyber security firm Symantec, in Mountain View, California, U.S. May 15, 2017. Courtesy of Symantec/Handout via REUTERS

SAN FRANCISCO (Reuters) - Cyber security firm Symantec Corp said on Monday it was "highly likely" a hacking group affiliated with North Korea was behind the WannaCry cyber attack this month that infected more than 300,000 computers worldwide and disrupted hospitals, banks and schools across the globe.

Symantec researchers said they had found multiple instances of code that had been used both in the North Korea-linked group's previous activity and in early versions of WannaCry.