Microsoft Scrambles To Patch Zero-Day Flaw In Windows Defender

Microsoft is scrambling to patch a zero-day flaw in Windows Defender after security researcher Nightmare-Eclipse revealed an exploit dubbed ShieldBreak. This exploit is an evolution of his previous RoguePlanet vulnerability, which was supposed to be patched by Microsoft's July Patch Tuesday.

ShieldBreak works on Windows 11, its Canary channel, and Windows Server 2025, with a 100% success rate. Although the PoC code only exists for Windows 11, it is likely that other versions of Windows, including Windows 10, are also vulnerable.

According to Malwarebytes, users can disable Defender to mitigate this exploit, but this will require an alternate antivirus/antimalware solution. Besides typical security advice like using 2FA and being wary of suspicious sites, there is not much that can be done until a patch is released.