Windows Cloud Files Filter Log Created by Non-System Process
Detects a non-system process causing creation of CldFlt0.etl under C:\Windows\System32\LogFiles\CloudFiles\. This path is initialised by the CldFlt driver when a process calls CfRegisterSyncRoot() or…
Description
Detects a non-system process causing creation of CldFlt0.etl under C:\Windows\System32\LogFiles\CloudFiles\. This path is initialised by the CldFlt driver when a process calls CfRegisterSyncRoot() or CfConnectSyncRoot(). In the RedSun exploit this is a side-effect of the DoCloudStuff() function that registers a fake sync provider to create the cloud-tagged bait file. Legitimate cloud providers (OneDrive etc.) register sync roots from SYSTEM-level service processes, not from user-context executables.
Detection logic
Detection requirements
- Platform
- ContainersLinuxmacOSWindows
The rule states no platform. This is derived from the ATT&CK technique it maps to.
- Log source category
- sysmon_eventid_11
Known benign triggers
- No false positives have been identified at this time.
MITRE ATT&CK mappings
0 exclusive techniques.This is coverage no other published rule has; it is not this rule's total technique count.
References
| Reference | Cited by |
|---|---|
| github.com/Nightmare-Eclipse/RedSun | 3 |
| www.huntress.com/blog/nightmare-eclipse-intrusion | 4 |
From the source
- At source
- Open at source
- Upstream identifier
- 2e0042b9-8a75-49ca-b3a2-948f04b752bf
- Tagged by the source as
- RedSunWindows Privilege EscalationEndpointendpointSplunk CloudSplunk EnterpriseSplunk Enterprise Securityendpoint
Licence
- Published under
- Apache License 2.0Read the licence
- Attribution
- Required
- Obtained under
- Apache-2.0Read the origin licence
Authorship
- Written by
- Published
- Aug 26, 2026
- Version
- 1