Remote Process Instantiation via WinRM and PowerShell
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
Kill Chain Phase
- Exploitation
NIST
CIS20
CVE
Search
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| 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:
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.
Supported Add-on (TA)
List of Splunk Add-on’s tested to work with the analytic.
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 |
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
- https://attack.mitre.org/techniques/T1021/006/
- https://pentestlab.blog/2018/05/15/lateral-movement-winrm/
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
source | version: 1