ShieldBreak Defender-triggered SYSTEM shell spawn (tightened)
Detects a SYSTEM-privileged cmd.exe/powershell.exe process spawned in close temporal/process proximity to Microsoft Defender's scanning process (MsMpEng.exe), consistent with successful exploitation of the ShieldBreak zero-day (CVE-2026-50656) TOCTOU bypass. Excludes known legitimate SYSTEM shell spawns from scheduled tasks, SCCM/Intune, and PsExec-style tooling.
Splunk (SPL)
