Detection: Windows Service Created Within Public Path

Updated Date: 2024-08-16 ID: 3abb2eda-4bb8-11ec-9ae4-3e22fbd008af Author: Mauricio Velazco, Splunk Type: TTP Product: Splunk Enterprise Security

Description

The following analytic detects the creation of a Windows Service with its binary path located in public directories using Windows Event ID 7045. This detection leverages logs from the wineventlog_system data source, focusing on the ImagePath field to identify services installed outside standard system directories. This activity is significant as it may indicate the installation of a malicious service, often used by adversaries for lateral movement or remote code execution. If confirmed malicious, this could allow attackers to execute arbitrary code, maintain persistence, or further compromise the system.

1`wineventlog_system` EventCode=7045 ImagePath = "*.exe" NOT (ImagePath IN ("*:\\Windows\\*", "*:\\Program File*", "*:\\Programdata\\*", "*%systemroot%\\*")) 
2| stats count min(_time) as firstTime max(_time) as lastTime by EventCode ImagePath ServiceName ServiceType StartType Computer UserID 
3| rename Computer as dest 
4| `security_content_ctime(firstTime)` 
5| `security_content_ctime(lastTime)` 
6| `windows_service_created_within_public_path_filter`

Data Source

Name Platform Sourcetype Source Supported App
Windows Event Log System 7045 Windows icon Windows 'xmlwineventlog' 'XmlWinEventLog:System' N/A

Macros Used

Name Value
security_content_ctime convert timeformat="%Y-%m-%dT%H:%M:%S" ctime($field$)
windows_service_created_within_public_path_filter search *
windows_service_created_within_public_path_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
T1543 Create or Modify System Process Persistence
T1543.003 Windows Service Privilege Escalation
KillChainPhase.EXPLOITAITON
KillChainPhase.INSTALLATION
NistCategory.DE_CM
Cis18Value.CIS_10
APT19
APT3
APT32
APT38
APT41
Blue Mockingbird
Carbanak
Cinnamon Tempest
Cobalt Group
DarkVishnya
Earth Lusca
FIN7
Ke3chang
Kimsuky
Lazarus Group
PROMETHIUM
TeamTNT
Threat Group-3390
Tropic Trooper
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 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 Service name, Service File Name Service Start type, and Service Type from your endpoints.

Known False Positives

Legitimate applications may install services with uncommon services paths.

Associated Analytic Story

Risk Based Analytics (RBA)

Risk Message Risk Score Impact Confidence
A Windows Service $ServiceName$ with a public path was created on $dest$ 54 90 60
The Risk Score is calculated by the following formula: Risk Score = (Impact * Confidence/100). Initial Confidence and Impact is set by the analytic author.

References

Detection Testing

Test Type Status Dataset Source Sourcetype
Validation ✅ Passing N/A N/A N/A
Unit ✅ Passing Dataset XmlWinEventLog:System XmlWinEventLog
Integration ✅ Passing Dataset XmlWinEventLog:System 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: 4