PowerShell Decompress via Expand-Archive
Alerts on PowerShell usage of Expand-Archive, a common decompression step attackers may use to unpack files.
- Product
- windows
- Category
- ps_module
- Author
- Roberto Rodriguez (Cyb3rWard0g), OTR (Open Threat Research) (SigmaHQ), DRL 1.1
- Published
- 2020-05-02
- Updated
- 2026-07-31
ATT&CK techniques
Defense EvasionRecon
Resource Dev
Initial Access
Execution
Persistence
Priv Esc
Defense Evasion
Cred Access
Discovery
Lateral Movement
Collection
C2
Exfiltration
Impact
What it detects
This rule matches PowerShell script module telemetry where the command payload contains the string "Expand-Archive". Adversaries can use archive extraction to unpack files during stealthy staging and follow-on execution. It relies on Windows PowerShell module logging that captures the executed payload content and supports substring matching for the target cmdlet name.
Reporting behind it
- github.comhttps://github.com/OTRF/detection-hackathon-apt29/issues/8
- github.comhttps://github.com/OTRF/ThreatHunter-Playbook/blob/2d4257f630f4c9770f78d0c1df059f891ffc3fec/docs/evals/apt29/detections/4.A.3_09F29912-8E93-461E-9E89-3F06F6763383.md
- github.comhttps://github.com/SigmaHQ/sigma/blob/master/rules/windows/powershell/powershell_module/posh_pm_decompress_commands.yml
Changelog
v2- v2Candidate ingested via manual entry.2026-07-31
- v1No 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.
title: PowerShell Decompress via Expand-Archive
id: fcb4079c-a1f5-4e1a-911d-cc2c2cbad00b
related:
- id: 81fbdce6-ee49-485a-908d-1a728c5dcb09
type: derived
- id: 1ddc1472-8e52-4f7d-9f11-eab14fc171f5
type: derived
status: test
description: This rule matches PowerShell script module telemetry where the command payload contains the string "Expand-Archive". Adversaries can use archive extraction to unpack files during stealthy staging and follow-on execution. It relies on Windows PowerShell module logging that captures the executed payload content and supports substring matching for the target cmdlet name.
references:
- https://github.com/OTRF/detection-hackathon-apt29/issues/8
- https://github.com/OTRF/ThreatHunter-Playbook/blob/2d4257f630f4c9770f78d0c1df059f891ffc3fec/docs/evals/apt29/detections/4.A.3_09F29912-8E93-461E-9E89-3F06F6763383.md
- https://github.com/SigmaHQ/sigma/blob/master/rules/windows/powershell/powershell_module/posh_pm_decompress_commands.yml
author: Roberto Rodriguez (Cyb3rWard0g), OTR (Open Threat Research), Huntrule Team
date: 2020-05-02
modified: 2022-12-25
tags:
- attack.stealth
- attack.t1140
logsource:
product: windows
category: ps_module
definition: 0ad03ef1-f21b-4a79-8ce8-e6900c54b65b
detection:
selection_4103:
Payload|contains: Expand-Archive
condition: selection_4103
falsepositives:
- Unknown
level: informational
license: DRL-1.1