SNAKE Malware Service Persistence

Status: test
Severity: critical
Log source: product windows, service system
Author: Nasreddine Bencherchali (Nextron Systems)
Source: github.com/SigmaHQ/sigma

Detects the creation of a service named "WerFaultSvc" which seems to be used by the SNAKE malware as a persistence mechanism as described by CISA in their report

MITRE ATT&CK coverage

Tactic	Techniques
Persistence	No specific technique

Telemetry coverage

Provider	Record / event type
Service-Control-Manager	Event ID 7045: A service was installed in the system.

Rule body

title: SNAKE Malware Service Persistence
id: b2e60816-96b2-45bd-ba91-b63578c03ef6
status: test
description: Detects the creation of a service named "WerFaultSvc" which seems to be used by the SNAKE malware as a persistence mechanism as described by CISA in their report
references:
    - https://media.defense.gov/2023/May/09/2003218554/-1/-1/0/JOINT_CSA_HUNTING_RU_INTEL_SNAKE_MALWARE_20230509.PDF
author: Nasreddine Bencherchali (Nextron Systems)
date: 2023-05-10
tags:
    - attack.persistence
    - detection.emerging-threats
logsource:
    product: windows
    service: system
detection:
    selection:
        Provider_Name: 'Service Control Manager'
        EventID: 7045
        ServiceName|contains: 'WerFaultSvc' # Note: The report contains a "," in the name ("WerFaultSvc,"). Since we can't confirm if its a typo or not we don't use it
        ImagePath|startswith: 'C:\Windows\WinSxS\'
        ImagePath|endswith: '\WerFault.exe'
    condition: selection
falsepositives:
    - Unknown
level: critical

Stages and Predicates

Stage 0: `condition`

selection

Stage 1: `selection`

selection:
    Provider_Name: 'Service Control Manager'
    EventID: 7045
    ServiceName|contains: 'WerFaultSvc'
    ImagePath|startswith: 'C:\Windows\WinSxS\'
    ImagePath|endswith: '\WerFault.exe'

Indicators

These rows show field, operator, and value matches.

Field	Kind	Values	Search
`ImagePath`	ends_with	`\WerFault.exe`	`field:"ImagePath" kind:ends_with value:"\WerFault.exe"`
`ImagePath`	starts_with	`C:\Windows\WinSxS\`	`field:"ImagePath" kind:starts_with value:"C:\Windows\WinSxS\"`
`Provider_Name`	eq	`Service Control Manager` corpus 50 (sigma 50)	`field:"Provider_Name" kind:eq value:"Service Control Manager"`
`ServiceName`	match	`WerFaultSvc`	`field:"ServiceName" kind:match value:"WerFaultSvc"`