Windows Office Product Spawned Child Process For Download

name: Windows Office Product Spawned Child Process For Download
id: f02b64b8-cbea-4f75-bf77-7a05111566b1
version: 9
date: '2026-04-15'
author: Teoderick Contreras, Splunk
status: production
type: TTP
description: The following analytic identifies Office applications spawning child processes to download content via HTTP/HTTPS. It leverages data from Endpoint Detection and Response (EDR) agents, focusing on process creation events where Office applications like Word or Excel initiate network connections, excluding common browsers. This activity is significant as it often indicates the use of malicious documents to execute living-off-the-land binaries (LOLBins) for payload delivery. If confirmed malicious, this behavior could lead to unauthorized code execution, data exfiltration, or further malware deployment, posing a severe threat to the organization's security.
data_source:
    - Sysmon EventID 1
    - Windows Event Log Security 4688
    - CrowdStrike ProcessRollup2
search: |
    | tstats `security_content_summariesonly` count min(_time) as firstTime max(_time)
    as lastTime from datamodel=Endpoint.Processes where
    `process_office_products_parent`
    Processes.process IN ("*http:*","*https:*")
    NOT (
      Processes.original_file_name IN ("firefox.exe", "chrome.exe","iexplore.exe","msedge.exe")
      OR
      Processes.process_name IN ("firefox.exe", "chrome.exe","iexplore.exe","msedge.exe")
    )
    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)`
    | `windows_office_product_spawned_child_process_for_download_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: Default browser not in the filter list.
references:
    - https://app.any.run/tasks/92d7ef61-bfd7-4c92-bc15-322172b4ebec/
    - https://www.trustwave.com/en-us/resources/blogs/spiderlabs-blog/trojanized-onenote-document-leads-to-formbook-malware/
drilldown_searches:
    - name: View the detection results for - "$dest$"
      search: '%original_detection_search% | search  dest = "$dest$"'
      earliest_offset: $info_min_time$
      latest_offset: $info_max_time$
    - name: View risk events for the last 7 days for - "$dest$"
      search: '| from datamodel Risk.All_Risk | search normalized_risk_object IN ("$dest$") | 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"
rba:
    message: Office document spawning suspicious child process on $dest$
    risk_objects:
        - field: dest
          type: system
          score: 50
    threat_objects: []
tags:
    analytic_story:
        - Spearphishing Attachments
        - CVE-2023-36884 Office and Windows HTML RCE Vulnerability
        - PlugX
        - NjRAT
        - APT37 Rustonotto and FadeStealer
    asset_type: Endpoint
    mitre_attack_id:
        - T1566.001
    product:
        - Splunk Enterprise
        - Splunk Enterprise Security
        - Splunk Cloud
    security_domain: endpoint
tests:
    - name: True Positive Test
      attack_data:
        - data: https://media.githubusercontent.com/media/splunk/attack_data/master/datasets/attack_techniques/T1566.001/datasets2/windows-sysmon.log
          source: XmlWinEventLog:Microsoft-Windows-Sysmon/Operational
          sourcetype: XmlWinEventLog