Suspicious Invoke-Obfuscation COMPRESS OBFUSCATION - Security (via security)

title: Suspicious Invoke-Obfuscation COMPRESS OBFUSCATION - Security (via security)
id: c50a79e0-b655-5f9b-be8e-d56240820458
status: stable
description: This rule detects Obfuscated Powershell via COMPRESS OBFUSCATION
references:
    - https://attack.mitre.org/techniques/T1059/001/
    - https://attack.mitre.org/techniques/T1027/
    - https://github.com/SigmaHQ/sigma/issues/1009
author: Huntrule Team
date: 2026-02-11
tags:
    - attack.stealth
    - attack.t1027
    - attack.execution
    - attack.t1059.001
logsource:
    product: windows
    service: security
    definition: The 'System Security Extension' audit subcategory need to be enabled to log the EID 4697
detection:
    selection:
        EventID: 4697
        ServiceFileName|contains|all:
            - 'new-object'
            - 'text.encoding]::ascii'
            - 'readtoend'
        ServiceFileName|contains:
            - 'system.io.compression.deflatestream'
            - 'system.io.streamreader'
    condition: selection
falsepositives:
    - Unknown
level: medium