DcRAT/Millenium RAT AMSI bypass via AmsiOpenSession in-memory patch

Ibrahim Saud@tektrix

•updated Jun 30, 2026•0•0•0

Detects potential Antimalware Scan Interface (AMSI) bypass attempts where a process loads amsi.dll followed by suspicious memory modification operations (e.g., VirtualProtect, WriteProcessMemory) targeting the AmsiOpenSession function or the amsi.dll memory space. This is a common technique used by malware like DcRAT and various loaders to neutralize endpoint security visibility.