windows_powershell_remotesigned_file.yml

name: Windows Powershell RemoteSigned File
id: f7f7456b-470d-4a95-9703-698250645ff4
version: 1
date: '2023-06-16'
author: Teoderick Contreras, Splunk
status: production
type: Anomaly
data_source:
- Sysmon EventID 1
description: This analytic identifies the use of "remotesigned" execution policy for
  a file. This security setting determines whether PowerShell scripts can be executed
  on a computer. When the execution policy is set to "remotesigned," it allows locally
  created scripts to run without any restrictions, but scripts downloaded from the
  internet must have a digital signature from a trusted publisher.
search: '| tstats `security_content_summariesonly` min(_time) as firstTime max(_time)
  as lastTime from datamodel=Endpoint.Processes where `process_powershell` Processes.process="*
  remotesigned *" Processes.process="* -File *" 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)` | `windows_powershell_remotesigned_file_filter`'
how_to_implement: The detection is based on data that originates from Endpoint Detection
  and Response (EDR) agents. These agents are designed to provide security-related
  telemetry from the endpoints where the agent is installed. To implement this search,
  you must ingest logs that contain the process GUID, process name, and parent process.
  Additionally, you must ingest complete command-line executions. These logs must
  be processed using the appropriate Splunk Technology Add-ons that are specific to
  the EDR product. The logs must also be mapped to the `Processes` node of the `Endpoint`
  data model. Use the Splunk Common Information Model (CIM) to normalize the field
  names and speed up the data modeling process.
known_false_positives: It is possible administrators or scripts may run these commands,
  filtering may be required.
references:
- https://learn.microsoft.com/en-us/powershell/module/microsoft.powershell.security/set-executionpolicy?view=powershell-7.3
tags:
  analytic_story:
  - Amadey
  asset_type: Endpoint
  confidence: 50
  impact: 50
  message: A PowerShell commandline with remotesigned policy executed on $dest$
  mitre_attack_id:
  - T1059.001
  - T1059
  observable:
  - name: dest
    type: Hostname
    role:
    - Victim
  - name: user
    type: User
    role:
    - Victim
  product:
  - Splunk Enterprise
  - Splunk Enterprise Security
  - Splunk Cloud
  risk_score: 25
  required_fields:
  - _time
  - Processes.dest
  - Processes.user
  - Processes.parent_process
  - Processes.process_name
  - Processes.original_file_name
  - Processes.process
  - Processes.process_id
  - Processes.parent_process_id
  security_domain: endpoint
tests:
- name: True Positive Test
  attack_data:
  - data: https://media.githubusercontent.com/media/splunk/attack_data/master/datasets/attack_techniques/T1059.001/powershell_remotesigned/remotesigned_sysmon.log
    source: XmlWinEventLog:Microsoft-Windows-Sysmon/Operational
    sourcetype: xmlwineventlog