Potential PowerShell Downgrade Attack

Title: Potential PowerShell Downgrade Attack
Status: test
Description:Detects PowerShell downgrade attack by comparing the host versions with the actually used engine version 2.0
References:
  -http://www.leeholmes.com/blog/2017/03/17/detecting-and-preventing-powershell-downgrade-attacks/
  -https://github.com/r00t-3xp10it/hacking-material-books/blob/43cb1e1932c16ff1f58b755bc9ab6b096046853f/obfuscation/simple_obfuscation.md#bypass-or-avoid-amsi-by-version-downgrade-
Author: Harish Segar (rule)
Date: 2020-03-20
modified:2023-01-04
Tags:

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

Logsource:

• category: process_creation
• product: windows

Detection:
  selection:
    Image|endswith: '\powershell.exe'
    CommandLine|contains:
      -' -version 2 '
      -' -versio 2 '
      -' -versi 2 '
      -' -vers 2 '
      -' -ver 2 '
      -' -ve 2 '
      -' -v 2 '

  condition:selection
Falsepositives:
  -Unknown
Level: medium