Detection rules › Sigma
VSS backup deletion or resize
Detects scenarios where an attacker attempts to delete or resize existing VSS backup.
Known false positives
- administrator cleaning outdated backup
MITRE ATT&CK coverage
| Tactic | Techniques |
|---|---|
| Impact |
Telemetry coverage
| Provider | Record / event type |
|---|---|
| Security-Auditing | Event ID 4688: A new process has been created. |
Rule body
title: VSS backup deletion or resize
description: Detects scenarios where an attacker attempts to delete or resize existing VSS backup.
references:
- https://www.picussecurity.com/resource/blog/how-to-beat-nefilim-ransomware-attacks
- https://www.itechtics.com/volume-shadow-copies/
- https://docs.microsoft.com/en-us/windows-server/administration/windows-commands/wbadmin
- https://www.picussecurity.com/resource/blog/technique-to-delete-volume-shadow-copies-deviceiocontrol
- https://thedfirreport.com/2021/12/13/diavol-ransomware/
- https://www.mandiant.com/resources/chasing-avaddon-ransomware
- https://blogs.vmware.com/security/2022/09/threat-report-illuminating-volume-shadow-deletion.html
- https://fourcore.io/blogs/ryuk-ransomware-simulation-mitre-ttp
tags:
- attack.impact
- attack.t1490
author: mdecrevoisier
status: experimental
logsource:
product: windows
category: process_creation
detection:
selection_baseline:
EventID: 4688
NewProcessName|endswith: '\vssadmin.exe'
selection_delete: # "vssadmin.exe delete shadows /all /quiet"
CommandLine|contains|all:
- shadows
- delete
selection_resize: # "vssadmin resize shadowstorage /for=c: /on=c: /maxsize=401MB"
CommandLine|contains|all:
- resize
- shadowstorage
condition: selection_baseline and (selection_delete or selection_resize)
falsepositives:
- administrator cleaning outdated backup
level: high
Stages and Predicates
Stage 0: condition
selection_baseline and (selection_delete or selection_resize)Stage 1: selection_baseline
selection_baseline:
EventID: 4688
NewProcessName|endswith: '\vssadmin.exe'
Stage 2: selection_delete
selection_delete:
CommandLine|contains|all:
- shadows
- delete
Stage 3: selection_resize
selection_resize:
CommandLine|contains|all:
- resize
- shadowstorage
Indicators
These rows show field, operator, and value matches.
| Field | Kind | Values | Search |
|---|---|---|---|
CommandLine | match |
| field:"CommandLine" kind:match |
NewProcessName | ends_with |
| field:"Image" kind:ends_with value:"\vssadmin.exe" |