A US cyber security firm says, hackers affiliated with North Korea were highly likely to be behind the ransomware attacks that have affected computers around the world. Releasing the findings from its investigation into the malware, Cyber security firm, Symantec, said they have found multiple similarities between the malware used in this attack and in a previous one believed to have been carried out by a group of North Korean hackers known as Lazarus. <br/><br/>The US government determined that the group was involved in the 2014 cyberattack on a subsidiary of Sony in the United States. They say the same IP address was used in both attacks. It also suspects that Lazarus stole large sums of money last year in an attack on Bangladesh's central bank. The new virus, called WannaCry, encrypts all files on a computer and demands 300 dollars in bitcoins to decrypt them. The US Government said the virus has infected more than 3 lakh devices in around 150 countries.