name: Logon Script Event Trigger Execution
id: 4c38c264-1f74-11ec-b5fa-acde48001122
version: 1
date: '2021-09-27'
author: Teoderick Contreras, Splunk
status: production
type: TTP
description: This search is to detect a suspicious modification of registry entry
  to persist and gain privilege escalation upon booting up of compromised host. This
  technique was seen in several APT and malware where it modify UserInitMprLogonScript
  registry entry to its malicious payload to be executed upon boot up of the machine.
data_source:
- Sysmon Event ID 13
search:
  selection1:
    TargetObject: '*\\Environment\\UserInitMprLogonScript'
  condition: selection1
how_to_implement: To successfully implement this search, you must be ingesting data
  that records registry activity from your hosts to populate the endpoint data model
  in the registry node. This is typically populated via endpoint detection-and-response
  product, such as Carbon Black or endpoint data sources, such as Sysmon. The data
  used for this search is typically generated via logs that report reads and writes
  to the registry.
known_false_positives: unknown
references:
- https://attack.mitre.org/techniques/T1037/001/
tags:
  analytic_story:
  - Windows Persistence Techniques
  - Windows Privilege Escalation
  - Hermetic Wiper
  asset_type: Endpoint
  confidence: 100
  impact: 80
  message: modified/added/deleted registry entry $Registry.registry_path$ in $dest$
  mitre_attack_id:
  - T1037
  - T1037.001
  observable:
  - name: dest
    type: Hostname
    role:
    - Victim
  - name: user
    type: User
    role:
    - Victim
  product:
  - Splunk Enterprise
  - Splunk Enterprise Security
  - Splunk Cloud
  risk_score: 80
  security_domain: endpoint
tests:
- name: True Positive Test
  attack_data:
  - data: https://media.githubusercontent.com/media/splunk/attack_data/master/datasets/attack_techniques/T1037.001/logonscript_reg/sysmon.log
    source: XmlWinEventLog:Microsoft-Windows-Sysmon/Operational
    sourcetype: xmlwineventlog