Researcher Releases BigDiskBuster Zero-Day PoC Blocking Microsoft Defender Updates

A zero-day proof-of-concept tool called BigDiskBuster, published on GitHub September 19, stops Microsoft Defender from installing platform and signature updates by filling all available disk space.

The tool has no patch, no CVE, and no Microsoft advisory. Its author, Abdelhamid Naceri (also known as Nightmare Eclipse), is a former Microsoft security researcher whose earlier Defender exploits have previously been used by attackers.