FUD Crypt — Signed Loader Kill Chain (Defender XDR / Sentinel)
UD Crypt (fudcrypt.net) is a Malware-as-a-Service crypter platform ($800–$2,000/month) that produces polymorphic Windows loaders carrying valid Microsoft-chained Authenticode signatures via Azure Trusted Signing abuse. The signature chains to the "Microsoft Identity Verification Root CA", bypassing SmartScreen and EV-signing checks. The loader abuses DLL sideloading into legitimate signed binaries (Zoom, Slack, VS Code, OneDrive, CCleaner, ProtonVPN, WindowsDF.exe → mpclient.dll), patches AMSI and ETW in-memory, masquerades the PEB as explorer.exe, and beacons via WSS to mstelemetrycloud.com. In a 38-day observation window: 200 operators, 334 builds, 2,093 C2 commands, 32 confirmed victims.
Microsoft Sentinel (KQL)
