Windows SpeechRuntime COM Hijacking DLL Load

name: Windows SpeechRuntime COM Hijacking DLL Load
id: bd35738c-e93a-4e4f-be24-f6a3680b950a
version: 4
date: '2026-03-10'
author: Raven Tait, Splunk
status: production
type: TTP
description: SpeechRuntime is vulnerable to an attack that allows a user to run code on another user's session remotely and stealthily by exploiting a Windows COM class. When this class is invoked, it launches SpeechRuntime.exe in the context of the currently logged-on user. Because this COM class is susceptible to COM Hijacking, the attacker can alter the registry remotely to point to a malicious DLL. By dropping that DLL on the target system (e.g., via SMB) and triggering the COM object, the attacker causes the malicious DLL to load into SpeechRuntime.exe and executing under the user's context. This detection identifies suspicious DLL loads by SpeechRuntime.exe from outside the expected locations.
data_source:
    - Sysmon EventID 7
search: |-
    `sysmon` EventCode=7 Image="*SpeechRuntime.exe"
      | eval image_loaded_lower = lower(ImageLoaded)
      | search NOT image_loaded_lower="*system32*"
      | fillnull
      | stats count min(_time) as firstTime max(_time) as lastTime
        BY Image ImageLoaded dest
           loaded_file loaded_file_path original_file_name
           parent_process_name parent_process_guid process_exec
           process_guid process_hash process_id
           process_name process_path service_dll_signature_exists
           service_dll_signature_verified signature signature_id
           user_id vendor_product
      | `security_content_ctime(firstTime)`
      | `security_content_ctime(lastTime)`
      | `windows_speechruntime_com_hijacking_dll_load_filter`
how_to_implement: To successfully implement this search, you need to be ingesting logs with the process name and ImageLoaded (Like sysmon EventCode 7) from your endpoints. If you are using Sysmon, you must have at least version 6.0.4 of the Sysmon TA. Also be sure to include those monitored dll to your own sysmon config.
known_false_positives: This process should normally never be loading dlls from outside the Windows system directory.
references:
    - https://github.com/rtecCyberSec/SpeechRuntimeMove
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: Possible Lateral Movement abusing Speech Runtime on $dest$
    risk_objects:
        - field: dest
          type: system
          score: 50
    threat_objects: []
tags:
    analytic_story:
        - Active Directory Lateral Movement
        - Compromised Windows Host
        - Scattered Lapsus$ Hunters
    asset_type: Endpoint
    mitre_attack_id:
        - T1021.003
    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/T1021.003/lateral_movement_speechruntime/windows-sysmon.log
          source: XmlWinEventLog:Microsoft-Windows-Sysmon/Operational
          sourcetype: XmlWinEventLog