Sigma rule: PowerShell Downgrade Attack - PowerShell

A detection rule from the SigmaHQ repository, shown as its author published it. Dataset version ref-e3064f8621bb, updated 2023-10-27T00:00:00.000Z.

Rule

Title
PowerShell Downgrade Attack - PowerShell
Status
test
Level
medium
Author
Florian Roth (Nextron Systems), Lee Holmes (idea), Harish Segar (improvements)
Date
2017-03-22
Modified
2023-10-27
File
rules/windows/powershell/powershell_classic/posh_pc_downgrade_attack.yml
Commit
ccbb0369507f796db0b0ae6854c8a2be471b9d84

Detects PowerShell downgrade attack by comparing the host versions with the actually used engine version 2.0

Log source

product
windows
category
ps_classic_start

Detection

selection:
    Data|contains: 'EngineVersion=2.'
filter_main:
    Data|contains: 'HostVersion=2.'
condition: selection and not filter_main

False positives (as the rule lists them)

  • Unknown

Tags

  • attack.execution
  • attack.t1059.001

MITRE ATT&CK ids this rule names

References

  • http://www.leeholmes.com/blog/2017/03/17/detecting-and-preventing-powershell-downgrade-attacks/

Read on 2026-11-03T00:58:21.399Z under licence sigma-drl-1.1@d5f4c36a from https://github.com/SigmaHQ/sigma/blob/ccbb0369507f796db0b0ae6854c8a2be471b9d84/rules/windows/powershell/powershell_classic/posh_pc_downgrade_attack.yml

Sources and licences

  • SigmaHQ

    "PowerShell Downgrade Attack - PowerShell" by Florian Roth (Nextron Systems), Lee Holmes (idea), Harish Segar (improvements) (SigmaHQ). Rule: https://github.com/SigmaHQ/sigma/blob/ccbb0369507f796db0b0ae6854c8a2be471b9d84/rules/windows/powershell/powershell_classic/posh_pc_downgrade_attack.yml.
    Licensed under the Detection Rule License (DRL) 1.1: https://github.com/SigmaHQ/Detection-Rule-License

    Detection Rule License (DRL) 1.1

Cite this page

Dragons Eye Ransomware Tracker, "Sigma rule: PowerShell Downgrade Attack - PowerShell",
entity page, dataset version ref-e3064f8621bb, updated 2023-10-27T00:00:00.000Z,
https://ransomware-tracker.com/detections/sigma/6331d09b-4785-4c13-980f-f96661356249 (accessed 2026-11-03).
Underlying source: SigmaHQ rule 6331d09b-4785-4c13-980f-f96661356249, commit ccbb0369507f796db0b0ae6854c8a2be471b9d84.

Pages change. The dataset version identifies the data, but no archive of old versions is kept, so this citation cannot be replayed later.