Windows Security: Detect Obfuscated PowerShell IEX Invocation via ServiceFileName Patterns (Event ID 4697)

Alerts on EventID 4697 instances where ServiceFileName matches obfuscated IEX-style PowerShell invocation patterns consistent with Invoke-Obfuscation.

FreeReviewedSigma · High · v2

Product: windows
Service: security
Author: Daniel Bohannon (@Mandiant/@FireEye), oscd.community (SigmaHQ), DRL 1.1
Published: 2019-11-08
Updated: 2026-07-31

Analysis Detection

ATT&CK techniques

Defense Evasion

Recon
Resource Dev
Initial Access
Execution
Persistence
Priv Esc
Defense Evasion
- T1027Obfuscated Files or Information
Cred Access
Discovery
Lateral Movement
Collection
C2
Exfiltration
Impact

What it detects

This rule flags Windows Security audit Event ID 4697 where the recorded service binary path contains specific strings consistent with obfuscated PowerShell IEX invocation patterns. Attackers commonly use obfuscation to evade command-line inspection and to hide the real payload delivery mechanism. Telemetry relies on the Security log producing Event ID 4697 along with the ServiceFileName field matching multiple predefined regular-expression patterns.

Reporting behind it

Related detections9 linkedT1027 — drag to rearrange

Suspicious PowerShell Invoke-Expression with Replace Obfuscation

Suspicious Base64 Decoded Payload Piped to Shell

Suspicious Shell Command Obfuscation via printf Escape Encoding on VMware ESXi (via process_creation)

Malicious Emmenhtal JavaScript Loader Spawning Encoded PowerShell

Suspicious Python Interpreter Launching Encoded PowerShell via subprocess

Suspicious PowerShell Download Of Text-Disguised Payload

Suspicious Encrypted Implant File Creation for DLL Search Order Hijacking (RainyDay Turian PlugX)

Suspicious PS1Bot PowerShell Payload Written to ProgramData (via file_event)

Malicious Non-Interactive Encoded PowerShell Stager (via process_creation)

Windows Security: Detect Obfuscated PowerShell IEX Invocation via ServiceFileName Patterns (Event ID 4697)

Pivot detection · T1027 · 9 related

Changelog

v2
Candidate ingested via manual entry.2026-07-31
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.

windows-security-event-4697-obfuscated-powershell-iex-invocation-pattern-from-in-fd0f5778

title: "Windows Security: Detect Obfuscated PowerShell IEX Invocation via ServiceFileName Patterns (Event ID 4697)"
id: bba8f149-30ae-4ae2-b511-12178b894952
related:
  - id: 51aa9387-1c53-4153-91cc-d73c59ae1ca9
    type: derived
  - id: fd0f5778-d3cb-4c9a-9695-66759d04702a
    type: derived
status: test
description: This rule flags Windows Security audit Event ID 4697 where the recorded service binary path contains specific strings consistent with obfuscated PowerShell IEX invocation patterns. Attackers commonly use obfuscation to evade command-line inspection and to hide the real payload delivery mechanism. Telemetry relies on the Security log producing Event ID 4697 along with the ServiceFileName field matching multiple predefined regular-expression patterns.
references:
  - https://github.com/danielbohannon/Invoke-Obfuscation/blob/f20e7f843edd0a3a7716736e9eddfa423395dd26/Out-ObfuscatedStringCommand.ps1#L873-L888
  - https://github.com/SigmaHQ/sigma/blob/master/rules/windows/builtin/security/win_security_invoke_obfuscation_obfuscated_iex_services_security.yml
author: Daniel Bohannon (@Mandiant/@FireEye), oscd.community, Huntrule Team
date: 2019-11-08
modified: 2022-11-27
tags:
  - attack.stealth
  - attack.t1027
logsource:
  product: windows
  service: security
  definition: The 'System Security Extension' audit subcategory need to be enabled to log the EID 4697
detection:
  selection_eid:
    EventID: 4697
  selection_servicefilename:
    - ServiceFileName|re: \$PSHome\[\s*\d{1,3}\s*\]\s*\+\s*\$PSHome\[
    - ServiceFileName|re: \$ShellId\[\s*\d{1,3}\s*\]\s*\+\s*\$ShellId\[
    - ServiceFileName|re: \$env:Public\[\s*\d{1,3}\s*\]\s*\+\s*\$env:Public\[
    - ServiceFileName|re: \$env:ComSpec\[(\s*\d{1,3}\s*,){2}
    - ServiceFileName|re: \\*mdr\*\W\s*\)\.Name
    - ServiceFileName|re: \$VerbosePreference\.ToString\(
    - ServiceFileName|re: \String\]\s*\$VerbosePreference
  condition: all of selection_*
falsepositives:
  - Unknown
level: high
license: DRL-1.1

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