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Description

This analytic looks for the execution of powershell.exe with arguments utilized to start a process on a remote endpoint by abusing the WinRM protocol. Specifically, this search looks for the abuse of the Invoke-Command commandlet. Red Teams and adversaries alike may abuse WinRM and powershell.exe for lateral movement and remote code execution.

  • Type: TTP
  • Product: Splunk Enterprise, Splunk Enterprise Security, Splunk Cloud
  • Datamodel: Endpoint
  • Last Updated: 2021-11-16
  • Author: Mauricio Velazco, Splunk
  • ID: ba24cda8-4716-11ec-8009-3e22fbd008af

Annotations

ATT&CK

ATT&CK

ID Technique Tactic
T1021 Remote Services Lateral Movement
T1021.006 Windows Remote Management Lateral Movement
Kill Chain Phase
  • Exploitation
NIST
CIS20
CVE
1
2
3
4
5
6
| tstats `security_content_summariesonly` count min(_time) as firstTime max(_time) as lastTime from datamodel=Endpoint.Processes where `process_powershell` (Processes.process="*Invoke-Command*" AND Processes.process="*-ComputerName*") by Processes.dest Processes.user Processes.parent_process_name 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)` 
| `remote_process_instantiation_via_winrm_and_powershell_filter`

Macros

The SPL above uses the following Macros:

:information_source: remote_process_instantiation_via_winrm_and_powershell_filter is a empty macro by default. It allows the user to filter out any results (false positives) without editing the SPL.

Required fields

List of fields required to use this analytic.

  • _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

How To Implement

To successfully implement this search, you need to be ingesting logs with the process name, parent process, and command-line executions from your endpoints.

Known False Positives

Administrators may leverage WinRM and Invoke-Command to start a process on remote systems for system administration or automation use cases. However, this activity is usually limited to a small set of hosts or users.

Associated Analytic Story

RBA

Risk Score Impact Confidence Message
45.0 90 50 A process was started on a remote endpoint from $dest by abusing WinRM using PowerShell.exe

:information_source: The Risk Score is calculated by the following formula: Risk Score = (Impact * Confidence/100). Initial Confidence and Impact is set by the analytic author.

Reference

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

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