huntrule

Windows Security: New or Renamed User Account Name Containing '$'

Alerts on Windows user create/rename events when the account name contains '$', excluding the HomeGroupUser$ exception.

FreeReviewedSigma · Medium · v2
Product
windows
Service
security
Author
Ilyas Ochkov, oscd.community (SigmaHQ), DRL 1.1
Published
2019-10-25
Updated
2026-07-31
AnalysisDetection

ATT&CK techniques

Defense Evasion

  1. Recon

  2. Resource Dev

  3. Initial Access

  4. Execution

  5. Persistence

  6. Priv Esc

  7. Defense Evasion

  8. Cred Access

  9. Discovery

  10. Lateral Movement

  11. Collection

  12. C2

  13. Exfiltration

  14. Impact

What it detects

This rule flags Windows Security events where a user account is created or renamed and the account name contains the '$' character. Attackers may use this to obscure naming and potentially bypass simpler detections that do not account for special characters in user names. The detection relies on Windows account management telemetry from EventID 4720 (user created) and EventID 4781 (user renamed), inspecting SamAccountName and NewTargetUserName fields while excluding the specific HomeGroupUser$ pattern.

Reporting behind it

Related detections9 linkedT1036 — drag to rearrange
Suspicious EAGERBEE Configuration File Created in Public User Directory via File Event
Malicious DLL Execution With Non Standard Extension via rundll32
Suspicious Rclone Exfiltration Masquerading as wininit.exe
Suspicious Executable Running from Public Pictures Directory
Suspicious Python Execution via Renamed Synaptics Binary
Agent Tesla Persistence via Realtek Named Scheduled Task Batch
Suspicious Interlock Fake Updater Executable Execution
Malicious User Account Created by a Computer Account (via security)
Suspicious Execution of agent.exe From WinSyncDefender AppData Directory (via process_creation)
Windows Security: New or Renamed User Account Name Containing '$'
Pivot detection · T1036 · 9 related

Changelog

v2
  1. v2
    Candidate ingested via manual entry.2026-07-31
  2. v1
    No changelog recorded for this version.2026-07-30

Detection content is published as a reviewed draft. Tune thresholds and exclusions against your own telemetry before enabling this rule for alerting.