splunk-security_content/detections/endpoint/detect_mshta_inline_hta_execution.yml

name: Detect mshta inline hta execution
id: a0873b32-5b68-11eb-ae93-0242ac130002
version: 8
date: '2024-08-15'
author: Bhavin Patel, Michael Haag, Splunk
status: production
type: TTP
description: The following analytic detects the execution of "mshta.exe" with inline
  protocol handlers such as "JavaScript", "VBScript", and "About". It leverages data
  from Endpoint Detection and Response (EDR) agents, focusing on command-line arguments
  and process details. This activity is significant because mshta.exe can be exploited
  to execute malicious scripts, potentially leading to unauthorized code execution.
  If confirmed malicious, this could allow an attacker to execute arbitrary code,
  escalate privileges, or establish persistence within the environment, posing a severe
  security risk.
data_source:
- Sysmon EventID 1
- Windows Event Log Security 4688
- CrowdStrike ProcessRollup2
search: '| tstats `security_content_summariesonly` count values(Processes.process)
  as process values(Processes.parent_process) as parent_process min(_time) as firstTime
  max(_time) as lastTime from datamodel=Endpoint.Processes where `process_mshta` (Processes.process=*vbscript*
  OR Processes.process=*javascript* OR Processes.process=*about*) by Processes.user
  Processes.process_name Processes.original_file_name Processes.parent_process_name
  Processes.dest  | `drop_dm_object_name(Processes)` | `security_content_ctime(firstTime)`|
  `security_content_ctime(lastTime)` | `detect_mshta_inline_hta_execution_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: Although unlikely, some legitimate applications may exhibit
  this behavior, triggering a false positive.
references:
- https://github.com/redcanaryco/AtomicTestHarnesses
- https://redcanary.com/blog/introducing-atomictestharnesses/
- https://docs.microsoft.com/en-us/windows/win32/search/-search-3x-wds-extidx-prot-implementing
tags:
  analytic_story:
  - Suspicious MSHTA Activity
  - Living Off The Land
  - Gozi Malware
  asset_type: Endpoint
  confidence: 100
  impact: 90
  message: An instance of $parent_process_name$ spawning $process_name$ was identified
    on endpoint $dest$ by user $user$ executing with inline HTA, indicative of defense
    evasion.
  mitre_attack_id:
  - T1218
  - T1218.005
  observable:
  - name: user
    type: User
    role:
    - Victim
  - name: dest
    type: Hostname
    role:
    - Victim
  - name: parent_process_name
    type: Process
    role:
    - Attacker
  - name: process_name
    type: Process
    role:
    - Attacker
  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: 90
  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