PowerShell Deleted Mounted Share — Sigma Rule

Rule metadata and linked tags

Author: oscd.community, @redcanary, Zach Stanford @svch0st. Source status: test; severity: medium. Source dates: 2020-10-08 / 2025-10-07.

{
  "product": "windows",
  "category": "ps_script",
  "definition": "Requirements: Script Block Logging must be enabled"
}

Pinned original Sigma rule · Detection Rule License 1.1

Source SHA-256: fbfd77c7f2d239f9b3bde720ef09c58063bf80d0ea56173c325ebfb38c2bbd37

Detection logic

Original source YAML. Source-tag agreement is not proof of complete semantic coverage. This rule has not been compiled for a SIEM backend or validated against live telemetry here.

title: PowerShell Deleted Mounted Share
id: 66a4d409-451b-4151-94f4-a55d559c49b0
status: test
description: Detects when when a mounted share is removed. Adversaries may remove share connections that are no longer useful in order to clean up traces of their operation
references:
    - https://github.com/redcanaryco/atomic-red-team/blob/f339e7da7d05f6057fdfcdd3742bfcf365fee2a9/atomics/T1070.005/T1070.005.md
author: 'oscd.community, @redcanary, Zach Stanford @svch0st'
date: 2020-10-08
modified: 2025-10-07
tags:
    - attack.stealth
    - attack.t1070.005
logsource:
    product: windows
    category: ps_script
    definition: 'Requirements: Script Block Logging must be enabled'
detection:
    selection:
        ScriptBlockText|contains:
            - 'Remove-SmbShare'
            - 'Remove-FileShare'
    filter_main_module_load:
        ScriptBlockText|contains|all:
            - 'FileShare.cdxml'
            - 'Microsoft.PowerShell.Core\Export-ModuleMember'
            - 'ROOT/Microsoft/Windows/Storage/MSFT_FileShare'
            - 'ObjectModelWrapper'
            - 'Cmdletization.MethodParameter'
    condition: selection and not 1 of filter_main_*
falsepositives:
    - Administrators or Power users may remove their shares via cmd line
level: medium

Original YAML and metadata in JSON

False positives

• Administrators or Power users may remove their shares via cmd line

Source references

• https://github.com/redcanaryco/atomic-red-team/blob/f339e7da7d05f6057fdfcdd3742bfcf365fee2a9/atomics/T1070.005/T1070.005.md