name: Powershell COM Hijacking InprocServer32 Modification
id: ea61e291-af05-4716-932a-67faddb6ae6f
version: 1
date: '2022-09-26'
author: Michael Haag, Splunk
type: TTP
datamodel:
- Endpoint
description: The following analytic utilizes PowerShell ScriptBlock Logging to identify a script that is attempting to modify or add a component object model to inprocserver32 path within the registry.
search: '`powershell` EventCode=4104 ScriptBlockText = "*Software\\Classes\\CLSID\\*\\InProcServer32*" | stats count min(_time)
  as firstTime max(_time) as lastTime by EventCode ScriptBlockText Computer UserID | `security_content_ctime(firstTime)`
  | `security_content_ctime(lastTime)` | `powershell_com_hijacking_inprocserver32_modification_filter`'
how_to_implement: The following analytic requires PowerShell operational logs
  to be imported. Modify the PowerShell macro as needed to match the sourcetype or
  add index. This analytic is specific to 4104, or PowerShell Script Block Logging.
known_false_positives: False positives will be present if any scripts are adding to inprocserver32. Filter as needed.
references:
  - https://attack.mitre.org/techniques/T1546/015/
  - https://www.splunk.com/en_us/blog/security/hunting-for-malicious-powershell-using-script-block-logging.html
  - https://blog.cluster25.duskrise.com/2022/09/23/in-the-footsteps-of-the-fancy-bear-powerpoint-graphite/
  - https://github.com/redcanaryco/atomic-red-team/blob/master/atomics/T1546.015/T1546.015.md
tags:
  analytic_story:
  - Malicious PowerShell
  asset_type: Endpoint
  cis20:
  - CIS 3
  - CIS 5
  - CIS 16
  confidence: 80
  context:
  - Source:Endpoint
  - Stage:Defense Evasion
  dataset:
  - https://media.githubusercontent.com/media/splunk/attack_data/master/datasets/attack_techniques/T1546.015/atomic_red_team/windows-powershell.log
  impact: 80
  kill_chain_phases:
  - Exploitation
  - Installation
  message: A PowerShell script has been identified with InProcServer32 within the script code on $Computer$.
  mitre_attack_id:
  - T1546.015
  - T1059
  - T1059.001
  nist:
  - DE.CM
  observable:
  - name: Computer
    type: Hostname
    role:
    - Victim
  product:
  - Splunk Enterprise
  - Splunk Enterprise Security
  - Splunk Cloud
  required_fields:
  - _time
  - ScriptBlockText
  - Opcode
  - Computer
  - UserID
  - EventCode
  risk_score: 64
  security_domain: endpoint