Network-Level Authentication (NLA) Disabled

Identifies the attempt to disable Network-Level Authentication (NLA) via registry modification. Network Level Authentication (NLA) is a feature on Windows that provides an extra layer of security for Remote Desktop (RDP) connections, as it requires users to authenticate before allowing a full RDP session. Attackers can disable NLA to enable persistence methods that require access to the Windows sign-in screen without authenticating, such as Accessibility Features persistence methods, like Sticky Keys.

Rule type: eql

Rule indices:

logs-endpoint.events.registry-*
endgame-*
logs-m365_defender.event-*
logs-sentinel_one_cloud_funnel.*
logs-windows.sysmon_operational-*

Severity: low

Risk score: 21

Runs every: 5m

Searches indices from: now-9m (Date Math format, see also Additional look-back time)

Maximum alerts per execution: 100

References:

https://www.microsoft.com/en-us/security/blog/2023/08/24/flax-typhoon-using-legitimate-software-to-quietly-access-taiwanese-organizations/

Tags:

Domain: Endpoint
OS: Windows
Use Case: Threat Detection
Tactic: Defense Evasion
Data Source: Elastic Defend
Data Source: Elastic Endgame
Data Source: Microsoft Defender for Endpoint
Data Source: SentinelOne
Data Source: Sysmon

Version: 203

Rule authors:

Elastic

Rule license: Elastic License v2

Rule query

edit

registry where host.os.type == "windows" and event.action != "deletion" and registry.value : "UserAuthentication" and
  registry.path : (
    "HKLM\\SYSTEM\\ControlSet*\\Control\\Terminal Server\\WinStations\\RDP-Tcp\\UserAuthentication",
    "\\REGISTRY\\MACHINE\\SYSTEM\\*ControlSet*\\Control\\Terminal Server\\WinStations\\RDP-Tcp\\UserAuthentication",
    "MACHINE\\SYSTEM\\*ControlSet*\\Control\\Terminal Server\\WinStations\\RDP-Tcp\\UserAuthentication"
  ) and registry.data.strings :  ("0", "0x00000000")

Framework: MITRE ATT&CK^TM

Tactic:
- Name: Defense Evasion
- ID: TA0005
- Reference URL: https://attack.mitre.org/tactics/TA0005/
Technique:
- Name: Modify Registry
- ID: T1112
- Reference URL: https://attack.mitre.org/techniques/T1112/
Technique:
- Name: Impair Defenses
- ID: T1562
- Reference URL: https://attack.mitre.org/techniques/T1562/

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