New Windows Defender zero-day blocks Microsoft antivirus updates

Security researcher Abdelhamid Naceri (Nightmare Eclipse) disclosed a new Windows Defender zero-day vulnerability named BigDiskBuster, which allows standard users to block Microsoft antivirus definition updates by preventing Defender from performing platform and signature updates. The exploit affects all supported Windows versions and must run in the background to be effective. This is part of an ongoing series of zero-day releases by the researcher in response to a dispute with Microsoft, who has patched some but not all of the disclosed flaws.

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