Windows 0-day dropped by disgruntled researcher hands hackers System rights

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• Ars Technica
  Windows 0-day dropped by disgruntled researcher hands hackers System rights

  Nightmare Eclipse, the pseudonym of a researcher with an ongoing, very public beef with Microsoft, has dropped yet another Windows zero-day. On Tuesday, Nightmare Eclipse disclosed SignDrop, a vulnerability that gives local users full System rights on some versions of Windows. The vulnerability resides in the Common Log File System , which Microsoft describes as a “general-purpose logging service used by software clients running in user-mode or kernel-mode.” By forcing a privileged process such as Windows Defender to open a crafted CLFS container, an attacker with ordinary user rights can abuse the privileged file creation to elevate privileges to System. Turning a Windows defense against itself The attack exploits the interaction of CLFS, Windows Defender, and Windows file permissions. The exploit uses Windows Defender to open a log file created by a standard user by calling ServerMpUpdateEngineSignature, a legitimate Defender function for processing antivirus signature updates. Read full article Comments ]]>

  Fri, 13 Nov 2026 16:26:32 GMT

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1. 2026-11-13 16:26Ars Technica — Windows 0-day dropped by disgruntled researcher hands hackers System rights