Nightmare Eclipse Drops Windows Zero-Day Exploit ‘SignDrop’
At a glance
Low rather than Medium: UK relevance is 40 of 100, little UK-specific signal so far.
Briefing
- IT leaders should assess if their systems are vulnerable to this zero-day exploit linked to the Nightmare Eclipse group.
Next steps
- Confirm whether this affects systems or suppliers in your estate
- The exploit leverages CLFS and Windows Defender to trigger arbitrary file creation in the antimalware process context.
Next steps
- Review the advisory against your asset inventory and patch cadence
Summary
- A Windows zero-day exploit called 'SignDrop' has been linked to the Nightmare Eclipse group, according to reports.
- The exploit uses CLFS and Windows Defender to create arbitrary files within the antimalware process context.
Part of The SignDrop zero-day exploit
Pulse
Last change 1h ago · Next recheck 14 Nov 2026, 09:02 UK time
- Story13 Nov 2026, 09:02 UK time · 1h ago
Linked reporting from SecurityWeek (independent original reporting).
Read source (SecurityWeek)
1 entry so far. The timeline chart appears once this story has more history.
Sources
- SecurityWeekNews
Nightmare Eclipse Drops Windows Zero-Day Exploit ‘SignDrop’
How we know
Statements extracted from sources. Higher confidence means stronger corroboration.
- ClaimedHeadline60% confidence
Nightmare Eclipse Drops Windows Zero-Day Exploit ‘SignDrop’
- ProbableSummary fact75% confidence
It abuses CLFS and Windows Defender to trigger arbitrary file creation in the context of the antimalware process. The post Nightmare Eclipse Drops Windows Zero-Day Exploit ‘SignDrop’ appeared first on SecurityWeek. Nightmare Eclipse Drops Windows Zero-Day Exploit ‘SignDrop’ This website stores cookies on your computer.