Detection: Windows SpeechRuntime COM Hijacking DLL Load

Updated Date: 2025-08-22 ID: bd35738c-e93a-4e4f-be24-f6a3680b950a Author: Raven Tait, Splunk Type: TTP Product: Splunk Enterprise Security

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.

Search

1`sysmon` EventCode=7 Image="*SpeechRuntime.exe" 
2| eval image_loaded_lower = lower(ImageLoaded) 
3| search NOT image_loaded_lower="*system32*" 
4| fillnull 
5| 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 
6| `security_content_ctime(firstTime)` 
7| `security_content_ctime(lastTime)` 
8| `windows_speechruntime_com_hijacking_dll_load_filter`

Data Source

Name	Platform	Sourcetype	Source
Sysmon EventID 7	Windows	`'XmlWinEventLog'`	`'XmlWinEventLog:Microsoft-Windows-Sysmon/Operational'`

Macros Used

Name	Value
security_content_ctime	`convert timeformat="%Y-%m-%dT%H:%M:%S" ctime($field$)`
windows_speechruntime_com_hijacking_dll_load_filter	`search *`

windows_speechruntime_com_hijacking_dll_load_filter is an empty macro by default. It allows the user to filter out any results (false positives) without editing the SPL.

Annotations

- MITRE ATT&CK

+ Kill Chain Phases

+ NIST

+ CIS

- Threat Actors

ID	Technique	Tactic
T1021.003	Distributed Component Object Model	Lateral Movement

Exploitation

DE.CM

CIS 10

Default Configuration

This detection is configured by default in Splunk Enterprise Security to run with the following settings:

Setting	Value
Disabled	true
Cron Schedule	`0 * * * *`
Earliest Time	`-70m@m`
Latest Time	`-10m@m`
Schedule Window	`auto`
Creates Notable	Yes
Rule Title	`%name%`
Rule Description	`%description%`
Notable Event Fields	user, dest
Creates Risk Event	True

This configuration file applies to all detections of type TTP. These detections will use Risk Based Alerting and generate Notable Events.

Implementation

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.

Associated Analytic Story

Risk Based Analytics (RBA)

Risk Message:

Possible Lateral Movement abusing Speech Runtime on $dest$

Risk Object	Risk Object Type	Risk Score	Threat Objects
dest	system	55	No Threat Objects

References

https://github.com/rtecCyberSec/SpeechRuntimeMove

Detection Testing

Test Type	Status	Dataset	Source	Sourcetype
Validation	✅ Passing	N/A	N/A	N/A
Unit	✅ Passing	Dataset	`XmlWinEventLog:Microsoft-Windows-Sysmon/Operational`	`XmlWinEventLog`
Integration	✅ Passing	Dataset	`XmlWinEventLog:Microsoft-Windows-Sysmon/Operational`	`XmlWinEventLog`

Replay any dataset to Splunk Enterprise by using our replay.py tool or the UI. Alternatively you can replay a dataset into a Splunk Attack Range

Source: GitHub | Version: 1