"If users or administrators detect the custom tools indicative of HIDDEN COBRA, these tools should be immediately flagged, reported to the DHS National Cybersecurity Communications and Integration Center or the FBI Cyber Watch, and given highest priority for enhanced mitigation," the alert said.

The DHS and FBI identified Internet Protocol addresses associated with a malware variant, known as "DeltaCharlie," which is used to manage the North's s distributed denial-of-service botnet infrastructure, the alert said.

It also included indicators of compromise, malware descriptions, network signatures, and host-based rules to help network defenders detect activity conducted by the North Korean government. (Yonhap)