Office Product Spawning MSHTA

SPLUNK detection rule by Michael Haag, Splunk · Apache-2.0

The following analytic has been deprecated in favour of a more generic approach in "Windows Office Product Spawned Uncommon Process". The following analytic identifies instances where a Microsoft Office product spawns `mshta.exe`. This detection leverages data from Endpoint Detection and Response (EDR) agents, focusing on process creation events where the parent process is an Office application. This activity is significant because it is a common technique used by malware families like TA551 and IcedID to execute malicious scripts or payloads. If confirmed malicious, this behavior could allow attackers to execute arbitrary code, potentially leading to data exfiltration, system compromise, or further malware deployment.

name: Office Product Spawning MSHTA
id: 6078fa20-a6d2-11eb-b662-acde48001122
version: 9
creation_date: '2021-04-27'
modification_date: '2026-05-13'
author: Michael Haag, Splunk
status: removed
type: TTP
description: The following analytic has been deprecated in favour of a more generic approach in "Windows Office Product Spawned Uncommon Process". The following analytic identifies instances where a Microsoft Office product spawns `mshta.exe`. This detection leverages data from Endpoint Detection and Response (EDR) agents, focusing on process creation events where the parent process is an Office application. This activity is significant because it is a common technique used by malware families like TA551 and IcedID to execute malicious scripts or payloads. If confirmed malicious, this behavior could allow attackers to execute arbitrary code, potentially leading to data exfiltration, system compromise, or further malware deployment.
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 Processes.parent_process_name IN ("winword.exe","excel.exe","powerpnt.exe","mspub.exe","visio.exe", "onenote.exe","onenotem.exe", "msaccess.exe","Graph.exe","winproj.exe") `process_mshta` by Processes.dest Processes.user Processes.parent_process_name Processes.parent_process Processes.process_name Processes.original_file_name Processes.process Processes.process_id Processes.parent_process_id | `drop_dm_object_name(Processes)` | `security_content_ctime(firstTime)`| `security_content_ctime(lastTime)` | `office_product_spawning_mshta_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: No false positives known. Filter as needed.
references:
    - https://redcanary.com/threat-detection-report/threats/TA551/
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 ("$dest$") starthoursago=168  | 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: $info_min_time$
      latest_offset: $info_max_time$
rba:
    message: Office process $parent_process_name$ observed executing a suspicious child process $process_name$ with process id $process_id$ on host $dest$
    risk_objects:
        - field: dest
          type: system
          score: 63
    threat_objects:
        - field: process_name
          type: process_name
tags:
    analytic_story:
        - Azorult
        - Spearphishing Attachments
        - IcedID
        - Compromised Windows Host
        - NjRAT
        - CVE-2023-36884 Office and Windows HTML RCE Vulnerability
    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/macro/windows-sysmon_macros.log
            source: XmlWinEventLog:Microsoft-Windows-Sysmon/Operational
            sourcetype: XmlWinEventLog
deprecation_info:
    reason: Detection deprecated as it no longer effectively identifies the intended malicious activity
    removed_in_version: 5.2.0
    replacement_content:
        - Windows Office Product Spawned Uncommon Process

[[ currentRule.title && currentRule.title.length > 60 ? currentRule.title.slice(0, 60) + '…' : currentRule.title ]]

4f2e8624-a03a-4eb4-9d5d-be7df735f8b7

Propose edits, view related rules, and engage with the community through comments.

Executable code, not a declarative rule

This submission is arbitrary [[ currentRule.format ? currentRule.format.toUpperCase() : '' ]] code, not a declarative detection rule — review it as you would any script before running it, and note that it cannot be safely aggregated or auto-executed alongside YARA/Sigma/Suricata/CRS rules.

Rejected pattern present

[[ reason ]]

What does this mean?

Format & documentation suggestions

Not a security issue — this rule is valid and was accepted as-is. These are optional fields/conventions its own format recommends, mainly affecting its quality score and how well it documents itself for other reviewers.

[[ reason ]]

What do these messages mean?

[[ currentRule.title && currentRule.title.length > 60 ? currentRule.title.slice(0, 60) + '…' : currentRule.title ]]

[[ currentRule.title ]]

Community Discussion