Try in Splunk Security Cloud

Description

The following analytic detects the creation of a new service named WerFaultSvc with a binary path in the Windows WinSxS directory. It leverages Windows System logs, specifically EventCode 7045, to identify this activity. This behavior is significant because it indicates the presence of Snake malware, which uses this service to maintain persistence by blending in with legitimate Windows services. If confirmed malicious, this activity could allow an attacker to execute Snake malware components, leading to potential data exfiltration, system compromise, and long-term persistence within the environment.

  • Type: TTP

  • Product: Splunk Enterprise, Splunk Enterprise Security, Splunk Cloud

  • Last Updated: 2024-05-13
  • Author: Michael Haag, Splunk
  • ID: 64eb091f-8cab-4b41-9b09-8fb4942377df

Annotations

ATT&CK

ATT&CK

ID Technique Tactic
T1547.006 Kernel Modules and Extensions Persistence, Privilege Escalation
T1569.002 Service Execution Execution
Kill Chain Phase
  • Installation
  • Exploitation
NIST
  • DE.CM
CIS20
  • CIS 10
CVE 


1
2
3
4
5
6



`wineventlog_system` EventCode=7045  ImagePath="*\\windows\\winSxS\\*" ImagePath="*\Werfault.exe" 
| stats count min(_time) as firstTime max(_time) as lastTime by Computer EventCode ImagePath ServiceName ServiceType 
| rename Computer as dest 
| `security_content_ctime(firstTime)` 
| `security_content_ctime(lastTime)` 
| `windows_snake_malware_service_create_filter`

Macros

The SPL above uses the following Macros:

:information_source: windows_snake_malware_service_create_filter is a empty macro by default. It allows the user to filter out any results (false positives) without editing the SPL.

Required fields

List of fields required to use this analytic.

  • EventCode
  • Service_File_Name
  • Service_Type
  • _time
  • Service_Name
  • Service_Start_Type
  • Service_Account
  • user

How To Implement

To successfully implement this search, you need to be ingesting Windows System logs with the Service name, Service File Name Service Start type, and Service Type from your endpoints.

Known False Positives

False positives should be limited as this is a strict primary indicator used by Snake Malware.

Associated Analytic Story

RBA

Risk Score Impact Confidence Message
72.0 80 90 A service, WerFaultSvc, was created on $dest$ and is related to Snake Malware.

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

Reference

Test Dataset

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 | version: 2