splunk-security_content/docs/_posts/2021-08-25-getnettcpconnection_with_powershell.md

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

title	excerpt	categories	last_modified_at	toc	toc_label	tags
GetNetTcpconnection with PowerShell	System Network Connections Discovery	Endpoint	2021-08-25	true		System Network Connections Discovery Discovery Splunk Enterprise Splunk Enterprise Security Splunk Cloud Endpoint

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Description

This analytic looks for the execution of powershell.exe with command-line utilized to get a listing of network connections on a compromised system. The Get-NetTcpConnection commandlet lists the current TCP connections. Red Teams and adversaries alike may use this commandlet for situational awareness and Active Directory Discovery.

• Type: Hunting
• Product: Splunk Enterprise, Splunk Enterprise Security, Splunk Cloud
• Datamodel: Endpoint
• Last Updated: 2021-08-25
• Author: Mauricio Velazco, Splunk
• ID: e02af35c-1de5-4afe-b4be-f45aba57272b

ATT&CK

ID	Technique	Tactic
T1049	System Network Connections Discovery	Discovery

Search

| tstats `security_content_summariesonly` count min(_time) as firstTime max(_time) as lastTime from datamodel=Endpoint.Processes where (Processes.process_name="powershell.exe") (Processes.process=*Get-NetTcpConnection*) by Processes.dest Processes.user Processes.parent_process Processes.process_name Processes.process Processes.process_id Processes.parent_process_id 
| `drop_dm_object_name(Processes)` 
| `security_content_ctime(firstTime)` 
| `security_content_ctime(lastTime)` 
| `getnettcpconnection_with_powershell_filter`

Associated Analytic Story

• Active Directory Discovery

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.

Required field

• 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

• Reconnaissance

Known False Positives

Administrators or power users may use this command for troubleshooting.

RBA

Risk Score	Impact	Confidence	Message
15.0	30	50	Network Connection discovery on dest by user

Reference

• https://attack.mitre.org/techniques/T1049/
• https://docs.microsoft.com/en-us/powershell/module/nettcpip/get-nettcpconnection?view=windowsserver2019-ps

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/T1049/AD_discovery/windows-sysmon.log

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