PowerShell Module Obfuscated IEX Invocation via Invoke-Obfuscation Payload Patterns

Alerts when PowerShell module payloads contain patterns consistent with obfuscated IEX generation via Invoke-Obfuscation.

FreeReviewedSigma · High · v2

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

Analysis Detection

ATT&CK techniques

Execution → Defense Evasion

Recon
Resource Dev
Initial Access
Execution
- T1059.001PowerShell
Persistence
Priv Esc
Defense Evasion
- T1027Obfuscated Files or Information
Cred Access
Discovery
Lateral Movement
Collection
C2
Exfiltration
Impact

What it detects

This rule identifies obfuscated PowerShell invocation patterns consistent with Invoke-Obfuscation-generated code that ultimately results in IEX-style execution. Such obfuscation is commonly used to evade basic script inspection and signature-based detections, so catching distinctive payload construction markers is valuable. It relies on PowerShell module telemetry with access to the command payload content that matches specific regular expressions in the rule.

Reporting behind it

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Malicious Non-Interactive Encoded PowerShell Stager (via process_creation)

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PowerShell Encoded or Download-Cradle Command Line (via process_creation)

Obfuscated Encoded PowerShell Payload Deployed - PowerShell (via powershell)

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PowerShell Module Obfuscated IEX Invocation via Invoke-Obfuscation Payload Patterns

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.

powershell-module-obfuscated-invoke-expression-iex-payloads-from-invoke-obfuscat-2f211361

title: PowerShell Module Obfuscated IEX Invocation via Invoke-Obfuscation Payload Patterns
id: 44ac0c7b-a1d9-487f-8885-71ded80c6965
related:
  - id: 1b9dc62e-6e9e-42a3-8990-94d7a10007f7
    type: derived
  - id: 2f211361-7dce-442d-b78a-c04039677378
    type: derived
status: test
description: This rule identifies obfuscated PowerShell invocation patterns consistent with Invoke-Obfuscation-generated code that ultimately results in IEX-style execution. Such obfuscation is commonly used to evade basic script inspection and signature-based detections, so catching distinctive payload construction markers is valuable. It relies on PowerShell module telemetry with access to the command payload content that matches specific regular expressions in the rule.
references:
  - https://github.com/danielbohannon/Invoke-Obfuscation/blob/f20e7f843edd0a3a7716736e9eddfa423395dd26/Out-ObfuscatedStringCommand.ps1#L873-L888
  - https://github.com/SigmaHQ/sigma/blob/master/rules/windows/powershell/powershell_module/posh_pm_invoke_obfuscation_obfuscated_iex.yml
author: Daniel Bohannon (@Mandiant/@FireEye), oscd.community, Huntrule Team
date: 2019-11-08
modified: 2022-12-31
tags:
  - attack.stealth
  - attack.t1027
  - attack.execution
  - attack.t1059.001
logsource:
  product: windows
  category: ps_module
  definition: 0ad03ef1-f21b-4a79-8ce8-e6900c54b65b
detection:
  selection_payload:
    - Payload|re: \$PSHome\[\s*\d{1,3}\s*\]\s*\+\s*\$PSHome\[
    - Payload|re: \$ShellId\[\s*\d{1,3}\s*\]\s*\+\s*\$ShellId\[
    - Payload|re: \$env:Public\[\s*\d{1,3}\s*\]\s*\+\s*\$env:Public\[
    - Payload|re: \$env:ComSpec\[(\s*\d{1,3}\s*,){2}
    - Payload|re: \*mdr\*\W\s*\)\.Name
    - Payload|re: \$VerbosePreference\.ToString\(
    - Payload|re: \[String\]\s*\$VerbosePreference
  condition: selection_payload
falsepositives:
  - Unknown
level: high
license: DRL-1.1

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