Detect mshta inline hta execution

name: Detect mshta inline hta execution
id: a0873b32-5b68-11eb-ae93-0242ac130002
version: 22
creation_date: '2020-04-29'
modification_date: '2026-05-13'
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 IN ("*vbscript*", "*javascript*", "*about*")

    by Processes.action Processes.dest Processes.original_file_name Processes.parent_process
       Processes.parent_process_exec Processes.parent_process_guid Processes.parent_process_id
       Processes.parent_process_name Processes.parent_process_path Processes.process
       Processes.process_exec Processes.process_guid Processes.process_hash
       Processes.process_id Processes.process_integrity_level Processes.process_name
       Processes.process_path Processes.user Processes.user_id Processes.vendor_product

    | `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
drilldown_searches:
    - name: View the detection results for - "$user$" and "$dest$"
      search: '%original_detection_search% | search  user = "$user$" dest = "$dest$"'
      earliest_offset: $info_min_time$
      latest_offset: $info_max_time$
    - name: View risk events for the last 7 days for - "$user$" and "$dest$"
      search: '| from datamodel Risk.All_Risk | search normalized_risk_object IN ("$user$", "$dest$") | stats count min(_time) as firstTime max(_time) as lastTime values(search_name) as "Search Name" values(risk_message) as "Risk Message" values(analyticstories) as "Analytic Stories" values(annotations._all) as "Annotations" values(annotations.mitre_attack.mitre_tactic) as "ATT&CK Tactics" by normalized_risk_object | `security_content_ctime(firstTime)` | `security_content_ctime(lastTime)`'
      earliest_offset: 7d
      latest_offset: "0"
finding:
    title: 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.
    entity:
        field: user
        type: user
        score: 50
intermediate_findings:
    entities:
        - field: dest
          type: system
          score: 50
          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.
threat_objects:
    - field: parent_process_name
      type: parent_process_name
    - field: process_name
      type: process_name
analytic_story:
    - Compromised Windows Host
    - Gozi Malware
    - Living Off The Land
    - Suspicious MSHTA Activity
    - XWorm
    - APT37 Rustonotto and FadeStealer
    - BlankGrabber Stealer
asset_type: Endpoint
mitre_attack_id:
    - T1218.005
product:
    - Splunk Enterprise
    - Splunk Enterprise Security
    - Splunk Cloud
category: endpoint
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
      test_type: unit