Diving into Hidden Scheduled Tasks

**Executive Summary:** This report expands on Microsoft’s findings about the ‘Tarrask’ malware technique that hides scheduled tasks by removing or altering the Security Descriptor (SD) registry value; ARC Labs demonstrates additional evasion methods (importing tasks, creating registry keys without SD, and setting deny SDDL entries) that can bypass Event Log and registry-auditing telemetry on Windows 10/11 and provides detection guidance, Sysmon rules, and a PowerShell hunt script to identify tampered or stealthy scheduled tasks.