name: Suspicious mshta spawn
id: 4d33a488-5b5f-11eb-ae93-0242ac130002
version: 2
date: '2021-01-20'
author: Michael Haag, Splunk
status: production
type: TTP
description: The following analytic identifies wmiprvse.exe spawning mshta.exe. This
  behavior is indicative of a DCOM object being utilized to spawn mshta from wmiprvse.exe
  or svchost.exe. In this instance, adversaries may use LethalHTA that will spawn
  mshta.exe from svchost.exe.
data_source:
- Sysmon Event ID 1
search:
  selection1:
    ParentImage:
    - svchost.exe
    - wmiprvse.exe
  selection2:
    OriginalFileName: MSHTA.EXE
  selection3:
    Image|endswith: mshta.exe
  condition: (selection1) and selection2 and selection3
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: Although unlikely, some legitimate applications may exhibit
  this behavior, triggering a false positive.
references:
- https://codewhitesec.blogspot.com/2018/07/lethalhta.html
- https://github.com/redcanaryco/AtomicTestHarnesses
- https://redcanary.com/blog/introducing-atomictestharnesses/
tags:
  analytic_story:
  - Suspicious MSHTA Activity
  - Living Off The Land
  asset_type: Endpoint
  confidence: 60
  impact: 70
  message: mshta.exe spawned by wmiprvse.exe on $dest$
  mitre_attack_id:
  - T1218
  - T1218.005
  observable:
  - name: dest
    type: Endpoint
    role:
    - Victim
  product:
  - Splunk Enterprise
  - Splunk Enterprise Security
  - Splunk Cloud
  risk_score: 42
  security_domain: endpoint
tests:
- name: True Positive Test
  attack_data:
  - data: https://media.githubusercontent.com/media/splunk/attack_data/master/datasets/attack_techniques/T1218.005/atomic_red_team/windows-sysmon.log
    source: XmlWinEventLog:Microsoft-Windows-Sysmon/Operational
    sourcetype: xmlwineventlog