Researcher Drops BigDiskBuster Zero-Day PoC That Blocks Microsoft Defender Updates

A zero-day proof-of-concept tool named BigDiskBuster, published on GitHub on September 19, blocks Microsoft Defender from installing platform and signature updates by filling all available disk space. It has no patch, CVE, or Microsoft advisory. Its author, Abdelhamid Naceri, is a former Microsoft security researcher whose earlier Defender exploits were used in attacks.