# Researcher releases tool that can block Microsoft Defender updates

_Published Tuesday, September 22, 2026 at 7:07 AM EDT · Security · Latest · Tier 2 — Notable_

![Researcher releases tool that can block Microsoft Defender updates — Primary](https://www.bleepstatic.com/content/hl-images/2026/06/17/Microsoft-Defender.jpg)

Security researcher Abdelhamid Naceri released a proof-of-concept tool that he says lets a standard Windows user prevent Microsoft Defender from receiving platform and signature updates. The tool, called BigDiskBuster, must remain running in the background and reportedly works across all supported Windows versions.

Blocking updates could leave Defender using outdated malware definitions even while the antivirus remains installed. Naceri described the proof of concept as buggy and in need of rewriting, and Microsoft had not commented when BleepingComputer sought a response.

## Sources

- [BleepingComputer](https://www.bleepingcomputer.com/news/security/new-windows-defender-zero-day-blocks-microsoft-antivirus-updates/)

---
Canonical: https://techandbusiness.org/newswire/uBwKqfaiNphMZe_1Fwcmnk
Published: 2026-09-22T11:07:36.868Z
Story chronology: 2026-09-22T09:55:11.000Z
Retrieved: 2026-09-22T12:57:02.994Z
Publisher: Tech & Business (techandbusiness.org)