threat may not be the only concerns about north korea. security experts tracking the global ransomware attack that affected 150 countries say the trail of clues could lead back to the north korean regime, which has a long record of computer criminality. cnn's alexandra field following the developments for us. she joins us live in seoul. good morning to you, alex. what do we know about this possible link? >> reporter: hey, dave. well, this is a massive attack, so it will take a while to get to the bottom of it, but there are leads, there is a direction to go in. here's how you get to the bottom of this, an attack that's generated some 300,000 cases, more than 150 countries. you've got security firms and researchers who are looking at the malware code, trying to match it to code used by other hackers in the past, known hackers. that may have been what led researchers to look at the lazarus group, a hacking group out of north korea. a top researcher out of google says there are similarities between the code used in this recent attack and code that's been generated by that group for their malware. those findings, those