name: Excel Spawning PowerShell
id: 42d40a22-9be3-11eb-8f08-acde48001122
version: 1
date: '2021-04-12'
author: Michael Haag, Splunk
type: batch
datamodel:
- Endpoint
description: The following detection identifies Microsoft Excel spawning PowerShell.
  Typically, this is not common behavior and not default with Excel.exe. Excel.exe
  will generally be found in the following path `C:\Program Files\Microsoft Office\root\Office16`
  (version will vary). PowerShell spawning from Excel.exe is common for a spearphishing
  attachment and is actively used. Albeit, the command executed will most likely be
  encoded and captured via another detection. During triage, review parallel processes
  and identify any files that may have been written.
search: '| tstats `security_content_summariesonly` count values(Processes.process)
  min(_time) as firstTime max(_time) as lastTime from datamodel=Endpoint.Processes
  where Processes.parent_process_name="excel.exe" Processes.process_name IN ("powershell.exe",
  "pwsh.exe")  by Processes.parent_process Processes.process_name Processes.user Processes.dest
  | `drop_dm_object_name("Processes")` | `security_content_ctime(firstTime)`|`security_content_ctime(lastTime)`
  | `excel_spawning_powershell_filter`'
how_to_implement: To successfully implement this search you need to be ingesting information
  on process that include the name of the process responsible for the changes from
  your endpoints into the `Endpoint` datamodel in the `Processes` node.
known_false_positives: False positives should be limited, but if any are present,
  filter as needed.
references:
- https://redcanary.com/threat-detection-report/techniques/powershell/
- https://attack.mitre.org/techniques/T1566/001/
tags:
  analytic_story:
  - Spearphishing Attachments
  automated_detection_testing: passed
  dataset:
  - https://media.githubusercontent.com/media/splunk/attack_data/master/datasets/attack_techniques/T1566.001/macro/windows-sysmon.log
  kill_chain_phases:
  - Exploitation
  mitre_attack_id:
  - T1003.002
  product:
  - Splunk Enterprise
  - Splunk Enterprise Security
  - Splunk Cloud
  required_fields:
  - _time
  - process_name
  - process_id
  - parent_process_name
  - dest
  - user
  - parent_process_id
  security_domain: endpoint