Proxy Execution via Vshadow

SIGMA detection rule by David Faiss · NOASSERTION

Detects the invocation of vshadow.exe with the -exec parameter that executes a specified script or command after the shadow copies are created but before the VShadow tool exits. VShadow is a command-line tool that you can use to create and manage volume shadow copies. While legitimate backup or administrative scripts may use this flag, attackers can leverage this parameter to proxy the execution of malware.

title: Proxy Execution via Vshadow
id: d7c75059-2901-4578-b209-8837fd31c6a8
status: experimental
description: |
    Detects the invocation of vshadow.exe with the -exec parameter that executes a specified script or command after the shadow copies are created but before the VShadow tool exits.
    VShadow is a command-line tool that you can use to create and manage volume shadow copies. While legitimate backup or administrative scripts may use this flag,
    attackers can leverage this parameter to proxy the execution of malware.
author: David Faiss
date: 2025-05-26
references:
    - https://lolbas-project.github.io/lolbas/OtherMSBinaries/Vshadow/
    - https://learn.microsoft.com/en-us/windows/win32/vss/vshadow-tool-and-sample
tags:
    - attack.stealth
    - attack.t1202
logsource:
    product: windows
    category: process_creation
detection:
    selection_img:
        - Image|endswith: '\vshadow.exe'
        - OriginalFileName: 'vshadow.exe'
    selection_cli:
        CommandLine|contains: '-exec'
    condition: all of selection_*
falsepositives:
    - System backup or administrator tools
    - Legitimate administrative scripts
level: medium

[[ currentRule.title && currentRule.title.length > 60 ? currentRule.title.slice(0, 60) + '…' : currentRule.title ]]

93f74d5d-eae1-4949-bad8-763d6de6025a

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Executable code, not a declarative rule

This submission is arbitrary [[ currentRule.format ? currentRule.format.toUpperCase() : '' ]] code, not a declarative detection rule — review it as you would any script before running it, and note that it cannot be safely aggregated or auto-executed alongside YARA/Sigma/Suricata/CRS rules.

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Format & documentation suggestions

Not a security issue — this rule is valid and was accepted as-is. These are optional fields/conventions its own format recommends, mainly affecting its quality score and how well it documents itself for other reviewers.

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