APT / THREAT GROUP
GRILLMARK
3
aliases
Last seen:Mar 17, 2026
Intelligence Profile
This is a proxy-aware HTTP backdoor that is implemented as a service and uses the compromised system's proxy settings to access the internet. C&C traffic is base64 encoded and the files sent to the server are compressed with aPLib.
Threat Analysis
GRILLMARK is a known-sophistication threat actor of undetermined national origin, engaged in cyber operations with a primary motivation of unknown activity patterns.
External References
Quick Facts
TypeAPT / Threat Group
Aliases3
Also Known As
GRILLMARKHellsing Backdoorwin.grillmark
External Intelligence
Malpedia: win.grillmarkResearch Links
Data sourced from Malpedia, Ransomware.live, RansomLook, and CTIWATCH OSINT collection. Actor attribution is based on available intelligence and may be incomplete.