Invoke-Obfuscation COMPRESS OBFUSCATION - PowerShell Module

Title: Invoke-Obfuscation COMPRESS OBFUSCATION - PowerShell Module
Status: test
Description:Detects Obfuscated Powershell via COMPRESS OBFUSCATION
References:
  -https://github.com/SigmaHQ/sigma/issues/1009
Author: Timur Zinniatullin, oscd.community
Date: 2020-10-18
modified:2022-11-29
Tags:

• -'attack.stealth'
• -'attack.t1027'
• -'attack.execution'
• -'attack.t1059.001'

Logsource:

• product: windows
• category: ps_module
• definition: 0ad03ef1-f21b-4a79-8ce8-e6900c54b65b

Detection:
  selection_4103:
    Payload|contains|all:
      -'new-object'
      -'text.encoding]::ascii'

    Payload|contains:
      -'system.io.compression.deflatestream'
      -'system.io.streamreader'

    Payload|endswith: 'readtoend'
  condition:selection_4103
Falsepositives:
  -Unknown
Level: medium