Microsoft Defender Updates Blocked by Naceri's Latest Zero-Day Exploit
Security researcher Abdelhamid Naceri has released another zero-day exploit targeting Microsoft Defender, dubbed BigDiskBuster. This tool blocks antivirus updates on all supported Windows versions and requires running in the background to be effective.
Naceri's latest creation is similar to UnDefend, a previous exploit that allowed standard users to block definition updates. The researcher claims that BigDiskBuster works similarly but may require some rewriting due to its buggy nature.
This release comes amid an ongoing dispute between Naceri and Microsoft over the latter's alleged unfair termination in March 2025. Naceri has released nearly a dozen zero-day exploits since April, targeting various Windows components and Defender vulnerabilities.