Lazarus has a long history of destructive cyber-attacks. Some more notable examples are the 2013 “Dark Seoul” attacks, the 2014 attack on Sony Pictures, a series of SWIFT-targeted campaigns in 2015-2016, and more. The researchers found a new set of MARs (Malware Analysis Reports) covering newly uncovered/updated malware/implants attributed to North Korea. More specifically, these are tools attributed to the Lazarus Group / Hidden Cobra.
Full Featured RAT (Remote Access Trojan) payloads and associated CAgent11 implant builder/controller. This implant is used for standard system management, control and recon. Initial infection is carried out via a malicious executable. An embedded bitmap image (contained in the trojan) is decoded into shellcode upon execution, thus loading the implant. Network communications are encrypted via XOR. The analyzed BISTROMATH samples, along with the other families all attempt to evade analysis via common sandboxes (VIRTUALBOX, QEMU, VMware) via multiple artifact checks (presence of specific devices, registry entries, processes, files).