Detection: First Time Seen Running Windows Service

Description

The following analytic detects the first occurrence of a Windows service running in your environment. It leverages Windows system event logs, specifically EventCode 7036, to identify services entering the "running" state. This activity is significant because the appearance of a new or previously unseen service could indicate the installation of unauthorized or malicious software. If confirmed malicious, this activity could allow an attacker to execute arbitrary code, maintain persistence, or escalate privileges within the environment. Monitoring for new services helps in early detection of potential threats.

Search

1`wineventlog_system` EventCode=7036 
2| rex field=Message "The (?<service>[-\(\)\s\w]+) service entered the (?<state>\w+) state" 
3| where state="running" 
4| lookup previously_seen_running_windows_services service as service OUTPUT firstTimeSeen 
5| where isnull(firstTimeSeen) OR firstTimeSeen > relative_time(now(), `previously_seen_windows_services_window`) 
6| table _time dest service 
7| `first_time_seen_running_windows_service_filter`

Data Source

Name	Platform	Sourcetype	Source
Windows Event Log System 7036	Windows	'xmlwineventlog'	'XmlWinEventLog:System'

Macros Used

Annotations

Default Configuration

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

Implementation

While this search does not require you to adhere to Splunk CIM, you must be ingesting your Windows system event logs in order for this search to execute successfully. You should run the baseline search Previously Seen Running Windows Services - Initial to build the initial table of child processes and hostnames for this search to work. You should also schedule at the same interval as this search the second baseline search Previously Seen Running Windows Services - Update to keep this table up to date and to age out old Windows Services. Please update the previously_seen_windows_services_window macro to adjust the time window. Please ensure that the Splunk Add-on for Microsoft Windows is version 8.0.0 or above.

Known False Positives

A previously unseen service is not necessarily malicious. Verify that the service is legitimate and that was installed by a legitimate process.

Associated Analytic Story

• NOBELIUM Group

• Orangeworm Attack Group

• Windows Service Abuse

Risk Based Analytics (RBA)

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: 6