Millenium RAT File Encryption: Mass Write in User Dirs + Shadow Copy Delete

Ibrahim Saud@tektrix

•updated Jun 30, 2026•1•0•2

Detects a suspicious pattern where a large volume of files (documents, archives, or media) are written to common user directories, followed within 10 minutes by attempts to impair system recovery (deleting shadow copies) or disable Microsoft Defender exclusions using native Windows utilities such as vssadmin, wmic, or PowerShell. This behavior is highly indicative of ransomware staging activities.