name: Malicious PowerShell Process - Encoded Command
id: c4db14d9-7909-48b4-a054-aa14d89dbb19
version: 5
date: '2020-07-21'
author: David Dorsey, Splunk
type: Hunting
datamodel:
- Endpoint
description: This search looks for PowerShell processes that have encoded the script
  within the command-line. Malware has been seen using this parameter, as it obfuscates
  the code and makes it relatively easy to pass a script on the command-line.
search: '| tstats `security_content_summariesonly` count min(_time) as firstTime max(_time)
  as lastTime from datamodel=Endpoint.Processes where `process_powershell` (Processes.process=*-EncodedCommand*
  OR Processes.process=*-enc*) by Processes.user Processes.process_name Processes.process
  Processes.parent_process_name Processes.original_file_name Processes.dest Processes.process_id
  | `drop_dm_object_name(Processes)` | `security_content_ctime(firstTime)`| `security_content_ctime(lastTime)`
  | `malicious_powershell_process___encoded_command_filter`'
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.
known_false_positives: System administrators may use this option, but it's not common.
references: []
tags:
  analytic_story:
  - Malicious PowerShell
  - NOBELIUM Group
  asset_type: Endpoint
  automated_detection_testing: passed
  cis20:
  - CIS 3
  - CIS 7
  - CIS 8
  confidence: 50
  context:
  - Source:Endpoint
  - Stage:Initial Access
  - Stage:Execution
  - Stage:Defense Evasion
  dataset:
  - https://media.githubusercontent.com/media/splunk/attack_data/master/datasets/attack_techniques/T1027/atomic_red_team/windows-sysmon.log
  impact: 70
  kill_chain_phases:
  - Command and Control
  - Actions on Objectives
  message: Powershell.exe running potentially malicious encodede commands on $dest$
  mitre_attack_id:
  - T1027
  nist:
  - PR.PT
  - DE.CM
  - PR.IP
  observable:
  - name: dest
    type: Endpoint
    role:
    - Victim
  product:
  - Splunk Enterprise
  - Splunk Enterprise Security
  - Splunk Cloud
  required_fields:
  - _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
  risk_score: 35
  security_domain: endpoint