Detection: Windows Outlook Dialogs Disabled from Unusual Process

Description

The following analytic detects the modification of the Windows Registry key "PONT_STRING" under Outlook Options. This disables certain dialog popups, which could allow malicious scripts to run without notice. This detection leverages data from the Endpoint.Registry datamodel to search for this key changing from an unusual process. 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\\Options\\General*" Registry.registry_value_name="PONT_STRING" 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| join process_guid [
 5| tstats `security_content_summariesonly` count FROM datamodel=Endpoint.Processes WHERE NOT (Processes.process_name = "Outlook.exe") by _time span=1h 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 
 6| `drop_dm_object_name(Processes)`] 
 7| fields _time parent_process_name parent_process process_name process_path process process_guid registry_path registry_value_name registry_value_data registry_key_name action dest user 
 8| `security_content_ctime(firstTime)` 
 9| `security_content_ctime(lastTime)` 
10| `windows_outlook_dialogs_disabled_from_unusual_process_filter`

Data Source

Name	Platform	Sourcetype	Source
Sysmon EventID 13	Windows	'XmlWinEventLog'	'XmlWinEventLog:Microsoft-Windows-Sysmon/Operational'

Macros Used

Annotations

Default Configuration

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

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 for processes other than Outlook to modify this feature on a Windows system since it is a default Outlook functionality. Although no false positives have been identified, use the provided filter macro to tune the search.

Associated Analytic Story

• NotDoor Malware

• Windows Registry Abuse

Risk Based Analytics (RBA)

Risk Message:

Outlook Dialog registry key modified on $dest$ by unusual process

References

• https://lab52.io/blog/analyzing-notdoor-inside-apt28s-expanding-arsenal/

• https://hackread.com/russian-apt28-notdoor-backdoor-microsoft-outlook/

Detection Testing

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