Detection: First Time Seen Running Windows Service

EXPERIMENTAL DETECTION

This detection status is set to experimental. The Splunk Threat Research team has not yet fully tested, simulated, or built comprehensive datasets for this detection. As such, this analytic is not officially supported. If you have any questions or concerns, please reach out to us at research@splunk.com.

Updated Date: 2024-05-21 ID: 823136f2-d755-4b6d-ae04-372b486a5808 Author: David Dorsey, Splunk Type: Anomaly Product: Splunk Enterprise Security

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	Supported App
Windows Event Log System 7036	Windows	`'xmlwineventlog'`	`'XmlWinEventLog:System'`	N/A

Macros Used

Name	Value
previously_seen_windows_services_window	`"-70m@m"`
first_time_seen_running_windows_service_filter	`search *`

first_time_seen_running_windows_service_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
T1569	System Services	Execution
T1569.002	Service Execution	Execution

KillChainPhase.INSTALLATION

NistCategory.DE_AE

Cis18Value.CIS_10

TeamTNT

APT32

APT38

APT39

APT41

Blue Mockingbird

Chimera

FIN6

Ke3chang

Silence

Wizard Spider

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 Risk Event	True

This configuration file applies to all detections of type anomaly. These detections will use Risk Based Alerting.

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

Risk Based Analytics (RBA)

Risk Message	Risk Score	Impact	Confidence
tbd	25	50	50

The Risk Score is calculated by the following formula: Risk Score = (Impact * Confidence/100). Initial Confidence and Impact is set by the analytic author.

Detection Testing

Test Type	Status	Dataset	Source	Sourcetype
Validation	Not Applicable	N/A	N/A	N/A
Unit	❌ Failing	N/A	`N/A`	`N/A`
Integration	❌ Failing	N/A	`N/A`	`N/A`

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: 5