The Department of Homeland Security and the Federal Bureau of Investigation issued a rare cybersecurity bulletin linking North Korea to a series of attacks that have targeted global businesses and critical infrastructure since 2009.
The alert focuses on a malware strain called DeltaCharlie, which DHS and FBI say was used by the North Korean government to launch distributed denial of service attacks. DDoS attacks use floods of web traffic from compromised devices to knock websites or services offline.
North Korea targeted "the media, aerospace, financial, and critical infrastructure sectors in the United States and globally," the alert says.
The US government refers to North Korea's hacking team as Hidden Cobra, but cybersecurity firms often use the slightly less sinister name Lazarus Group. The North Koreans have also been linked to the WannaCry ransomware that spread virally in May and shut down hospitals and businesses.
WannaCry primarily targeted unpatched Windows machines, and it sounds like the Lazarus Group's DDoS malware is also primarily exploiting devices that run old versions of Windows. "The multiple vulnerabilities in these older systems provide cyber actors many targets for exploitation," the alert notes.
Windows typically stops issuing patches for older operating systems after they have been retired, but the company today released patches that thwart WannaCry on outdated devices, ZDNet reports.
Although DHS and FBI released data that will help detect and mitigate Lazarus Group attacks, the agencies said more research is necessary to "understand the full breadth" of the group's capabilities.