
title: Invoke-Obfuscation COMPRESS OBFUSCATION
author: Timur Zinniatullin, oscd.community
date: 2020/10/18
description: Detects Obfuscated Powershell via COMPRESS OBFUSCATION
detection:
  SELECTION_1:
    ScriptBlockText|re: (?i).*new-object.*(?:system\.io\.compression\.deflatestream|system\.io\.streamreader).*text\.encoding\]::ascii.*readtoend
  condition: SELECTION_1
falsepositives:
- unknown
id: 20e5497e-331c-4cd5-8d36-935f6e2a9a07
level: medium
logsource:
  category: ps_script
  definition: Script block logging must be enabled
  product: windows
modified: 2021/10/16
references:
- https://github.com/Neo23x0/sigma/issues/1009
status: experimental
tags:
- attack.defense_evasion
- attack.t1027
- attack.execution
- attack.t1059.001
ruletype: SIGMA
