Microsoft left a kernel-level, zero-day bug in Windows for six months before patching it
Hackers exploited the issue to spread an extremely stealthy rootkit
Lazarus group articles
North Korean hackers are skimming card details from online shoppers
The notorious Lazarus Group has been linked to the attacks
Was North Korea behind disruptive cyberattack on multiple US newspapers?
Did the Lazarus Group strike again?
US says North Korea was "directly responsible" for WannaCry ransomware
Many experts have already blamed the Lazarus Group for WannaCry
Another security agency places blame for WannaCry on North Korea
The NSA and various security groups also suspect the hermit nation