Detection: Windows Service Create RemComSvc

Description

The following analytic detects the creation of the RemComSvc service on a Windows endpoint, typically indicating lateral movement using RemCom.exe. It leverages Windows EventCode 7045 from the System event log, specifically looking for the "RemCom Service" name. This activity is significant as it often signifies unauthorized lateral movement within the network, which is a common tactic used by attackers to spread malware or gain further access. If confirmed malicious, this could lead to unauthorized access to sensitive systems, data exfiltration, or further compromise of the network.

1`wineventlog_system` EventCode=7045 ServiceName="RemCom Service" 
2| stats count min(_time) as firstTime max(_time) as lastTime by dest ImagePath ServiceName ServiceType   
3| `security_content_ctime(firstTime)` 
4| `security_content_ctime(lastTime)` 
5| `windows_service_create_remcomsvc_filter`

Data Source

Name Platform Sourcetype Source
Windows Event Log System 7045 Windows icon Windows 'xmlwineventlog' 'XmlWinEventLog:System'

Macros Used

Name Value
security_content_ctime convert timeformat="%Y-%m-%dT%H:%M:%S" ctime($field$)
windows_service_create_remcomsvc_filter search *
windows_service_create_remcomsvc_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
T1543.003 Windows Service Persistence
T1543 Create or Modify System Process Privilege Escalation
KillChainPhase.EXPLOITAITON
KillChainPhase.INSTALLATION
NistCategory.DE_AE
Cis18Value.CIS_10
APT19
APT3
APT32
APT38
APT41
Agrius
Aquatic Panda
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 Risk Event True
This configuration file applies to all detections of type anomaly. These detections will use Risk Based Alerting.

Implementation

To implement this analytic, the Windows EventCode 7045 will need to be logged. The Windows TA for Splunk is also recommended.

Known False Positives

False positives may be present, filter as needed based on administrative activity.

Associated Analytic Story

Risk Based Analytics (RBA)

Risk Message Risk Score Impact Confidence
A new service was created related to RemCom on $dest$. 32 40 80
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: 3