sigmamediumHunting

Clear PowerShell History - PowerShell

Detects keywords that could indicate clearing PowerShell history

MITRE ATT&CK

defense-evasion

Detection Query

selection1a:
  ScriptBlockText|contains:
    - del
    - Remove-Item
    - rm
selection1b:
  ScriptBlockText|contains: (Get-PSReadlineOption).HistorySavePath
selection_2:
  ScriptBlockText|contains|all:
    - Set-PSReadlineOption
    - –HistorySaveStyle
    - SaveNothing
selection_3:
  ScriptBlockText|contains|all:
    - Set-PSReadlineOption
    - -HistorySaveStyle
    - SaveNothing
condition: 1 of selection_* or all of selection1*

Author

Ilyas Ochkov, Jonhnathan Ribeiro, Daniil Yugoslavskiy, oscd.community

Created

2022-01-25

Data Sources

windowsps_script

Platforms

windows

References

https://gist.github.com/hook-s3c/7363a856c3cdbadeb71085147f042c1a

Tags

attack.defense-evasionattack.t1070.003

Raw Content

title: Clear PowerShell History - PowerShell
id: 26b692dc-1722-49b2-b496-a8258aa6371d
related:
    - id: dfba4ce1-e0ea-495f-986e-97140f31af2d
      type: derived
status: test
description: Detects keywords that could indicate clearing PowerShell history
references:
    - https://gist.github.com/hook-s3c/7363a856c3cdbadeb71085147f042c1a
author: Ilyas Ochkov, Jonhnathan Ribeiro, Daniil Yugoslavskiy, oscd.community
date: 2022-01-25
modified: 2022-12-02
tags:
    - attack.defense-evasion
    - attack.t1070.003
logsource:
    product: windows
    category: ps_script
    definition: 'Requirements: Script Block Logging must be enabled'
detection:
    selection1a:
        ScriptBlockText|contains:
            - 'del'
            - 'Remove-Item'
            - 'rm'
    selection1b:
        ScriptBlockText|contains: '(Get-PSReadlineOption).HistorySavePath'
    selection_2:
        ScriptBlockText|contains|all:
            - 'Set-PSReadlineOption'
            - '–HistorySaveStyle'  # not sure if the homoglyph –/- is intended, just checking for both
            - 'SaveNothing'
    selection_3:
        ScriptBlockText|contains|all:
            - 'Set-PSReadlineOption'
            - '-HistorySaveStyle'
            - 'SaveNothing'
    condition: 1 of selection_* or all of selection1*
falsepositives:
    - Legitimate PowerShell scripts
level: medium