Detection: Windows Outlook LoadMacroProviderOnBoot Persistence

Updated Date: 2025-09-09 ID: 93c91139-01f8-4905-802b-0d106f026b13 Author: Raven Tait, Splunk Type: TTP Product: Splunk Enterprise Security

Description

The following analytic detects the modification of the Windows Registry key "LoadMacroProviderOnBoot" under Outlook. This enables automatic loading of macros, which could allow malicious scripts to run without notice. This detection leverages data from the Endpoint.Registry datamodel to search for this key being enabled. This activity is significant as it is commonly associated with some malware infections, indicating potential malicious intent to harvest email information.

Search

1
2| tstats `security_content_summariesonly` count FROM datamodel=Endpoint.Registry WHERE Registry.registry_path="*\\Outlook\\*" Registry.registry_value_name="LoadMacroProviderOnBoot" Registry.registry_value_data="0x00000001" by Registry.action Registry.dest Registry.process_guid Registry.process_id Registry.registry_hive Registry.registry_path Registry.registry_key_name Registry.registry_value_data Registry.registry_value_name Registry.registry_value_type Registry.status Registry.user Registry.vendor_product 
3| `drop_dm_object_name(Registry)` 
4| `security_content_ctime(firstTime)` 
5| `security_content_ctime(lastTime)` 
6| `windows_outlook_loadmacroprovideronboot_persistence_filter`

Data Source

Name	Platform	Sourcetype	Source
Sysmon EventID 13	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_outlook_loadmacroprovideronboot_persistence_filter	`search *`

windows_outlook_loadmacroprovideronboot_persistence_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
T1112	Modify Registry	Defense Evasion
T1137	Office Application Startup	Persistence

Exploitation

Installation

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 registry value name, registry path, and registry value data from your endpoints. If you are using Sysmon, you must have at least version 2.0 of the official Sysmon TA. https://splunkbase.splunk.com/app/5709

Known False Positives

It is unusual to modify this feature on a Windows system. Although no false positives have been identified, use the provided filter macro to tune the search.

Associated Analytic Story

Risk Based Analytics (RBA)

Risk Message:

Outlook LoadMacroProviderOnBoot registry key modified on $dest$

Risk Object	Risk Object Type	Risk Score	Threat Objects
dest	system	54	No Threat Objects

References

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