When Nation-States Become Ransomware Affiliates: Lazarus Group Deploys Medusa via a Custom IME-Based Loader
2026-03-17 • Break Glass Intelligence •
Breakglass analyzed two samples from a Hungarian incident as evidence that Lazarus Group operated as a Medusa ransomware-as-a-service affiliate rather than only deploying DPRK-built ransomware. The TSMSISrv.dll loader is attributed to Lazarus-linked tradecraft through detections and TTP matches, using Windows 8 IME SDK camouflage, SessionEnv DLL sideloading, COM hijacking persistence, dual TLS anti-analysis callbacks, and a custom AES implementation. The separate gaze.exe ransomware binary carries Medusa builder indicators, including a G:\Medusa\Release\gaze.pdb path, VS2019 x86 build characteristics, XOR-encoded configuration, Tor negotiation infrastructure, service-kill routines, and RSA/AES file encryption. Compilation timestamps place the loader in March 2025 and the ransomware in October 2025, supporting a patient intrusion followed by later extortion deployment. The finding matters because it suggests DPRK operators may bring their own access and persistence tooling into third-party ransomware ecosystems, complicating attribution and incident response.