Sigma rule: Potential Remote Desktop Connection to Non-Domain Host

A detection rule from the SigmaHQ repository, shown as its author published it. Dataset version ref-763fa0ede29c, updated 2021-11-27T00:00:00.000Z.

Rule

Title
Potential Remote Desktop Connection to Non-Domain Host
Status
test
Level
medium
Author
James Pemberton
Date
2020-05-22
Modified
2021-11-27
File
rules/windows/builtin/ntlm/win_susp_ntlm_rdp.yml
Commit
ccbb0369507f796db0b0ae6854c8a2be471b9d84

Detects logons using NTLM to hosts that are potentially not part of the domain.

Log source

product
windows
service
ntlm
definition
Requires events from Microsoft-Windows-NTLM/Operational

Detection

selection:
    EventID: 8001
    TargetName|startswith: 'TERMSRV'
condition: selection

False positives (as the rule lists them)

  • Host connections to valid domains, exclude these.
  • Host connections not using host FQDN.
  • Host connections to external legitimate domains.

Tags

  • attack.command-and-control
  • attack.t1219.002

MITRE ATT&CK ids this rule names

References

  • n/a

Read on 2026-11-03T00:58:21.399Z under licence sigma-drl-1.1@d5f4c36a from https://github.com/SigmaHQ/sigma/blob/ccbb0369507f796db0b0ae6854c8a2be471b9d84/rules/windows/builtin/ntlm/win_susp_ntlm_rdp.yml

Sources and licences

  • SigmaHQ

    "Potential Remote Desktop Connection to Non-Domain Host" by James Pemberton (SigmaHQ). Rule: https://github.com/SigmaHQ/sigma/blob/ccbb0369507f796db0b0ae6854c8a2be471b9d84/rules/windows/builtin/ntlm/win_susp_ntlm_rdp.yml.
    Licensed under the Detection Rule License (DRL) 1.1: https://github.com/SigmaHQ/Detection-Rule-License

    Detection Rule License (DRL) 1.1

Cite this page

Dragons Eye Ransomware Tracker, "Sigma rule: Potential Remote Desktop Connection to Non-Domain Host",
entity page, dataset version ref-763fa0ede29c, updated 2021-11-27T00:00:00.000Z,
https://ransomware-tracker.com/detections/sigma/ce5678bb-b9aa-4fb5-be4b-e57f686256ad (accessed 2026-11-03).
Underlying source: SigmaHQ rule ce5678bb-b9aa-4fb5-be4b-e57f686256ad, commit ccbb0369507f796db0b0ae6854c8a2be471b9d84.

Pages change. The dataset version identifies the data, but no archive of old versions is kept, so this citation cannot be replayed later.