title: Invoke-Obfuscation COMPRESS OBFUSCATION
author: Timur Zinniatullin, oscd.community
date: 2020/10/18
description: Detects Obfuscated Powershell via COMPRESS OBFUSCATION
detection:
    SELECTION_1:
        Payload|re: (?i).*new-object.*(?:system\.io\.compression\.deflatestream|system\.io\.streamreader).*text\.encoding\]::ascii.*readtoend
    condition: SELECTION_1
falsepositives:
- unknown
id: 7034cbbb-cc55-4dc2-8dad-36c0b942e8f1
level: medium
logsource:
    category: ps_module
    definition: PowerShell Module Logging must be enabled
    product: windows
modified: 2021/10/16
references:
- https://github.com/Neo23x0/sigma/issues/1009
related:
-   id: 20e5497e-331c-4cd5-8d36-935f6e2a9a07
    type: derived
status: experimental
tags:
- attack.defense_evasion
- attack.t1027
- attack.execution
- attack.t1059.001
yml_filename: powershell_invoke_obfuscation_via_compress.yml
yml_path: /Users/user/Documents/YamatoSecurity/sigma/rules/windows/powershell/powershell_module