A concrete conclusion could be weeks away.
Intelligence officials and private security experts say that new digital clues point to North Korean-linked hackers as likely suspects in the sweeping ransomware attacks that have crippled computer systems around the world.
The indicators are far from conclusive, the researchers warned, and it could be weeks, if not months, before investigators are confident enough in their findings to officially point the finger at Pyongyang’s increasingly bold corps of digital hackers. The attackers based their weapon on vulnerabilities that were stolen from the National Security Agency and published last month.
Security experts at Symantec, which in the past has accurately identified attacks mounted by the United States, Israel and North Korea, found early versions of the ransomware, called WannaCry, that used tools that were also deployed against Sony Pictures Entertainment, a Bangladesh Central Bank last year and Polish banks in February. American officials said Monday that they had seen the same similarities.