Detection rules › Splunk

Windows Snake Malware Service Create

Status
production
Severity
medium
Group by
ImagePath, ServiceType, computer_name, service_name, signature_id
Author
Michael Haag, Splunk
Source
github.com/splunk/security_content

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.

MITRE ATT&CK coverage

Event coverage

Rule body splunk

name: Windows Snake Malware Service Create
id: 64eb091f-8cab-4b41-9b09-8fb4942377df
version: 9
creation_date: '2023-05-11'
modification_date: '2026-05-13'
author: Michael Haag, Splunk
status: production
type: TTP
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.
data_source:
    - Windows Event Log System 7045
search: '`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`'
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.
references:
    - https://media.defense.gov/2023/May/09/2003218554/-1/-1/0/JOINT_CSA_HUNTING_RU_INTEL_SNAKE_MALWARE_20230509.PDF
drilldown_searches:
    - name: View the detection results for - "$dest$"
      search: '%original_detection_search% | search  dest = "$dest$"'
      earliest_offset: $info_min_time$
      latest_offset: $info_max_time$
    - name: View risk events for the last 7 days for - "$dest$"
      search: '| from datamodel Risk.All_Risk | search normalized_risk_object IN ("$dest$") | stats count min(_time) as firstTime max(_time) as lastTime values(search_name) as "Search Name" values(risk_message) as "Risk Message" values(analyticstories) as "Analytic Stories" values(annotations._all) as "Annotations" values(annotations.mitre_attack.mitre_tactic) as "ATT&CK Tactics" by normalized_risk_object | `security_content_ctime(firstTime)` | `security_content_ctime(lastTime)`'
      earliest_offset: 7d
      latest_offset: "0"
finding:
    title: A service, WerFaultSvc, was created on $dest$ and is related to Snake Malware.
    entity:
        field: dest
        type: system
        score: 50
analytic_story:
    - Snake Malware
    - Compromised Windows Host
asset_type: Endpoint
atomic_guid:
    - b8db787e-dbea-493c-96cb-9272296ddc49
mitre_attack_id:
    - T1547.006
    - T1569.002
product:
    - Splunk Enterprise
    - Splunk Enterprise Security
    - Splunk Cloud
category: endpoint
security_domain: endpoint
tests:
    - name: True Positive Test
      attack_data:
        - data: https://media.githubusercontent.com/media/splunk/attack_data/master/datasets/malware/snakemalware/snake-service-windows-system.log
          source: XmlWinEventLog:System
          sourcetype: XmlWinEventLog
      test_type: unit

Stages and Predicates

Stage 1: search

`wineventlog_system` EventCode=7045  ImagePath="*\\windows\\winSxS\\*" ImagePath="*\Werfault.exe"

Stage 2: stats

| stats count min(_time) as firstTime max(_time) as lastTime by Computer EventCode ImagePath ServiceName ServiceType

Stage 3: rename

| rename Computer as dest

Stage 4: search

| `security_content_ctime(firstTime)`

Stage 5: search

| `security_content_ctime(lastTime)`

Stage 6: search

| `windows_snake_malware_service_create_filter`

Indicators

Each row is a field, operator, and value that the rule matches. The corpus column counts how many other rules in the catalog look for the same combination: high numbers point to widely-used, community-vetted indicators. Blank or 1 shows that the indicator is specific to this rule.

FieldKindValues
EventCodeeq
  • 7045 corpus 20 (splunk 18, chronicle 1, kusto 1)
ImagePatheq
  • "*\Werfault.exe"
  • "*\\windows\\winSxS\\*"