Potential NetNTLMv1 Downgrade Attack
Identifies registry modification to force the system to fall back to NTLMv1 for authentication. This modification is possible with local administrator privileges and is commonly referred to as a `NetNTLMv1 downgrade…
Description
Identifies registry modification to force the system to fall back to NTLMv1 for authentication. This modification is possible with local administrator privileges and is commonly referred to as a `NetNTLMv1 downgrade attack`.
Detection logic
Its licence does not clear it for publishing here
Sunturai publishes a detection's own text where the licence it arrived under has been reviewed and permits it, and Elastic License 2.0 has not. The query as its source wrote it, its canonical form and the hash that pins this revision are in the workspace record.
Detection requirements
- Platform
- ContainersESXiIaaSIdentity ProviderLinuxmacOSNetwork DevicesOffice SuiteWindows
The rule states no platform. This is derived from the 3 ATT&CK techniques it maps to.
- Log source category
- event_index
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 |
|---|---|
| learn.microsoft.com/en-us/previous-versions/windows/it-pro/windows-10/security/threat-protection/security-policy-settings/network-security-lan-manager-authentication-level | Only this detection cites it |
From the source
- At source
- Open at source
- Upstream identifier
- 4d169db7-0323-4157-9ad3-ea5ece9019c9
- Tagged by the source as
- Data Source: CrowdstrikeData Source: Elastic DefendData Source: Elastic EndgameData Source: Microsoft Defender XDRData Source: SentinelOneData Source: SysmonDomain: EndpointNoise: LowOS: WindowsPerformance: NormalPlatform: WindowsResources: Investigation GuideRule Type: Event Correlation (EQL)Tactic: Defense EvasionUse Case: Threat Detection
Licence
- Published under
- Elastic License 2.0Read the licence
- Attribution
- Required
Authorship
- Written by
- Published
- Sep 20, 2026
- Version
- 3