Security researchers at Intezer and McAfee have conducted a joint investigation that allowed them to collect evidence that links malware families attributed to North Korean APT groups such as the notorious Lazarus Group and Group 123. North Korea-linked groups operated with two main goals, raise money and pursue nationalist aims. The experts analyzed thousands of malware samples, many still unclassified or uncategorized, and discovered many similarities in the source code used in attacks associated with North Korea. For example, the Common SMB module that was part of the WannaCry Ransomware was similar to the code used the malware Mydoom (2009) and DeltaAlfa.”]
Source: https://securityaffairs.co/wordpress/75227/malware/north-korea-malware-lazarus.html