'BigDiskBuster' Leaves Microsoft Defender Running While Blocking Updates

Researchers demonstrated a proof-of-concept technique, "BigDiskBuster," that can stop Microsoft Defender from receiving security intelligence updates while the Defender service continues to run normally. For CIOs and technology leaders, the business risk is a silent protection gap: endpoints may appear healthy and compliant while actually missing the latest detections, extending the window for malware persistence and increasing exposure across the fleet. IT organizations should treat security update integrity as an operational control, not just an application status check, and add monitoring for failed Defender updates, disk-usage anomalies, and related I/O behaviors.