A sophisticated cyber group capitalized on a combination of five “zero-day” vulnerabilities to target persons inside North Korea and foreign individuals working on DPRK-related issues last year, a report issued by Google’s Threat Analysis Group (TAG) said Thursday.

The report, which analyzed almost 40,000 warnings sent last year relating to government-backed phishing or malware attempts, drew particular attention to one actor as being responsible for some of the most sophisticated North Korea-related attacks.

“Last year, TAG discovered that a single threat actor was capitalizing on five zero-day vulnerabilities,” the analysis said. “The majority of targets we observed were from