splunk-security_content/docs/_posts/2021-04-12-winword_spawning_powershell.md

title, excerpt, categories, last_modified_at, toc, toc_label, tags

title	excerpt	categories	last_modified_at	toc	toc_label	tags
Winword Spawning PowerShell	Phishing, Spearphishing Attachment	Endpoint	2021-04-12	true		TTP T1566 Phishing Initial Access T1566.001 Spearphishing Attachment Initial Access Splunk Enterprise Splunk Enterprise Security Splunk Cloud Endpoint Exploitation

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Description

The following detection identifies Microsoft Word spawning PowerShell. Typically, this is not common behavior and not default with winword.exe. Winword.exe will generally be found in the following path C:\Program Files\Microsoft Office\root\Office16 (version will vary). PowerShell spawning from winword.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.

• Type: TTP
• Product: Splunk Enterprise, Splunk Enterprise Security, Splunk Cloud
• Datamodel: Endpoint
• Last Updated: 2021-04-12
• Author: Michael Haag, Splunk
• ID: b2c950b8-9be2-11eb-8658-acde48001122

ATT&CK

ID	Technique	Tactic
T1566	Phishing	Initial Access
T1566.001	Spearphishing Attachment	Initial Access

Search

| tstats `security_content_summariesonly` count min(_time) as firstTime max(_time) as lastTime from datamodel=Endpoint.Processes where Processes.parent_process_name="winword.exe" `process_powershell` by Processes.dest Processes.user Processes.parent_process Processes.process_name Processes.original_file_name Processes.process Processes.process_id Processes.parent_process_id 
| `drop_dm_object_name(Processes)` 
| `security_content_ctime(firstTime)`
| `security_content_ctime(lastTime)` 
| `winword_spawning_powershell_filter`

Associated Analytic Story

• Spearphishing Attachments

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. In addition, confirm the latest CIM App 4.20 or higher is installed and the latest TA for the endpoint product.

Required field

• _time
• Processes.dest
• Processes.user
• Processes.parent_process_name
• Processes.parent_process
• Processes.original_file_name
• Processes.process_name
• Processes.process
• Processes.process_id
• Processes.parent_process_path
• Processes.process_path
• Processes.parent_process_id

Kill Chain Phase

• Exploitation

Known False Positives

False positives should be limited, but if any are present, filter as needed.

RBA

Risk Score	Impact	Confidence	Message
70.0	70	100	parent_process_name on dest by user launched the following powershell process: process_name which is very common in spearphishing attacks

Reference

• https://redcanary.com/threat-detection-report/techniques/powershell/
• https://attack.mitre.org/techniques/T1566/001/
• https://app.any.run/tasks/b79fa381-f35c-4b3e-8d02-507e7ee7342f/
• https://app.any.run/tasks/181ac90b-0898-4631-8701-b778a30610ad/

Test Dataset

Replay any dataset to Splunk Enterprise by using our replay.py tool or the UI. Alternatively you can replay a dataset into a Splunk Attack Range

• https://media.githubusercontent.com/media/splunk/attack_data/master/datasets/attack_techniques/T1566.001/macro/windows-sysmon.log

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