huntrule

Windows PowerShell User Discovery via Current Username APIs

Alerts on PowerShell script blocks that retrieve the current username or user identity using common environment/.NET calls.

FreeReviewedSigma · Low · v2
Product
windows
Category
ps_script
Author
frack113 (SigmaHQ), DRL 1.1
Published
2022-04-04
Updated
2026-07-31
AnalysisDetection

ATT&CK techniques

Discovery

  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 PowerShell script block text that attempts to determine the current logged-in user by referencing username-related environment variables and .NET identity APIs. User discovery helps attackers tailor follow-on actions and validate execution context, so frequent or unexpected usage can be suspicious. It relies on Script Block Logging telemetry capturing PowerShell script content containing the specific username expressions.

Reporting behind it

Related detections9 linkedT1033 — drag to rearrange
Suspicious Whoami Discovery Spawned by Windows Script Host via Process Creation (via process_creation)
Suspicious Localized Administrator Account and Group Enumeration After Citrix Bleed Exploitation
Malicious Recon Output Staged in Qlik Sense Fonts Directory by Cactus Ransomware
Suspicious Host Reconnaissance Command Chain via cmd
Malicious Child Process Spawned From n8n Node Process
Suspicious Credential Enumeration via cmdkey List
Suspicious IIS Worker Process Spawning Whoami Reconnaissance
Suspicious Whoami Execution With Output Redirected to a File (via process_creation)
Possible Logged-On Session Discovery via Quser or Qwinsta (via process_creation)
Windows PowerShell User Discovery via Current Username APIs
Pivot detection · T1033 · 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.