Detection rules › Sigma
Potential PowerShell Downgrade Attack
Detects PowerShell downgrade attack by comparing the host versions with the actually used engine version 2.0
MITRE ATT&CK coverage
| Tactic | Techniques |
|---|---|
| Execution |
Telemetry coverage
| Provider | Record / event type |
|---|---|
| Sysmon | Event ID 1: Process creation |
| Security-Auditing | Event ID 4688: A new process has been created. |
Rule body
title: Potential PowerShell Downgrade Attack
id: b3512211-c67e-4707-bedc-66efc7848863
related:
- id: 6331d09b-4785-4c13-980f-f96661356249
type: derived
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
Stages and Predicates
Stage 0: condition
selectionStage 1: selection
selection:
Image|endswith: '\powershell.exe'
CommandLine|contains:
- ' -version 2 '
- ' -versio 2 '
- ' -versi 2 '
- ' -vers 2 '
- ' -ver 2 '
- ' -ve 2 '
- ' -v 2 '
Indicators
These rows show field, operator, and value matches.
| Field | Kind | Values | Search |
|---|---|---|---|
CommandLine | match |
| field:"CommandLine" kind:match |
Image | ends_with |
| field:"Image" kind:ends_with value:"\powershell.exe" |