Suspicious Volume Shadow Copy Vssapi.dll Load — Sigma Rule

Rule metadata and linked tags

Author: frack113. Source status: test; severity: high. Source dates: 2022-10-31 / 2026-05-18.

{
  "category": "image_load",
  "product": "windows"
}

Pinned original Sigma rule · Detection Rule License 1.1

Source SHA-256: 6d564b6f62383fe24c747194946781ad8cece0f07b26bde6cf9b95af32cfa4a7

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: Suspicious Volume Shadow Copy Vssapi.dll Load
id: 37774c23-25a1-4adb-bb6d-8bb9fd59c0f8
related:
    - id: 333cdbe8-27bb-4246-bf82-b41a0dca4b70 # vss_ps.dll
      type: similar
    - id: 48bfd177-7cf2-412b-ad77-baf923489e82 # vsstrace.dll
      type: similar
status: test
description: Detects the image load of VSS DLL by uncommon executables
references:
    - https://github.com/ORCx41/DeleteShadowCopies
author: frack113
date: 2022-10-31
modified: 2026-05-18
tags:
    - attack.impact
    - attack.t1490
logsource:
    category: image_load
    product: windows
detection:
    selection:
        ImageLoaded|endswith: '\vssapi.dll'
    filter_main_windows:
        - Image:
              - 'C:\Windows\explorer.exe'
              - 'C:\Windows\ImmersiveControlPanel\SystemSettings.exe'
        - Image|startswith:
              - 'C:\Windows\System32\'
              - 'C:\Windows\SysWOW64\'
              - 'C:\Windows\Temp\{' # Installers
              - 'C:\Windows\WinSxS\'
              - 'C:\$WinREAgent\Scratch\'
    filter_main_program_files:
        # When using this rule in your environment replace the "Program Files" folder by the exact applications you know use this. Examples would be software such as backup solutions
        Image|startswith:
            - 'C:\Program Files\'
            - 'C:\Program Files (x86)\'
    filter_main_null_image:
        Image: null
    filter_optional_programdata_packagecache:
        # The following filter is required because of many FPs cause by:
        #   C:\ProgramData\Package Cache\{10c6cfdc-27af-43fe-bbd3-bd20aae88451}\dotnet-sdk-3.1.425-win-x64.exe
        #   C:\ProgramData\Package Cache\{b9cfa33e-ace4-49f4-8bb4-82ded940990a}\windowsdesktop-runtime-6.0.11-win-x86.exe
        #   C:\ProgramData\Package Cache\{50264ff2-ad47-4569-abc4-1c350f285fb9}\aspnetcore-runtime-6.0.11-win-x86.exe
        #   C:\ProgramData\Package Cache\{2dcef8c3-1563-4149-a6ec-5b6c98500d7d}\dotnet-sdk-6.0.306-win-x64.exe
        #   etc.
        Image|startswith: 'C:\ProgramData\Package Cache\'
    filter_optional_avira:
        Image|contains|all:
            - '\temp\is-'
            - '\avira_system_speedup.tmp'
    condition: selection and not 1 of filter_main_* and not 1 of filter_optional_*
falsepositives:
    - Unknown
level: high

Original YAML and metadata in JSON

False positives

• Unknown

Source references

• https://github.com/ORCx41/DeleteShadowCopies