name: Windows Diskshadow Proxy Execution
id: 58adae9e-8ea3-11ec-90f6-acde48001122
version: 1
date: '2022-02-15'
author: Lou Stella, Splunk
status: production
type: TTP
description: DiskShadow.exe is a Microsoft Signed binary present on Windows Server.
  It has a scripting mode intended for complex scripted backup operations. This feature
  also allows for execution of arbitrary unsigned code. This analytic looks for the
  usage of the scripting mode flags in executions of DiskShadow. During triage, compare
  to known backup behavior in your environment and then review the scripts called
  by diskshadow.
data_source:
- Sysmon Event ID 1
search:
  selection1:
    OriginalFileName: diskshadow.exe
  selection2:
    Image|endswith: diskshadow.exe
  selection3:
    CommandLine:
    - '*-s*'
    - '*/s*'
  condition: (selection1 or selection2) and selection3
how_to_implement: To successfully implement this search you need to be ingesting information
  on processes that include the name of the process responsible for the changes from
  your endpoints into the `Endpoint` datamodel in the `Processes` node. In addition,confirm
  the latest CIM App 4.20 or higher is installed and the latest TA for the endpoint
  product.
known_false_positives: Administrators using the DiskShadow tool in their infrastructure
  as a main backup tool with scripts will cause false positives that can be filtered
  with `windows_diskshadow_proxy_execution_filter`
references:
- https://bohops.com/2018/03/26/diskshadow-the-return-of-vss-evasion-persistence-and-active-directory-database-extraction/
tags:
  analytic_story:
  - Living Off The Land
  asset_type: Endpoint
  confidence: 70
  impact: 70
  message: Possible Signed Binary Proxy Execution on $dest$
  mitre_attack_id:
  - T1218
  observable:
  - name: dest
    type: Hostname
    role:
    - Victim
  product:
  - Splunk Enterprise
  - Splunk Enterprise Security
  - Splunk Cloud
  risk_score: 49
  security_domain: endpoint
tests:
- name: True Positive Test
  attack_data:
  - data: https://media.githubusercontent.com/media/splunk/attack_data/master/datasets/attack_techniques/T1218/diskshadow/windows-sysmon.log
    source: XmlWinEventLog:Microsoft-Windows-Sysmon/Operational
    sourcetype: xmlwineventlog