Suspicious RazerInstaller Explorer Subprocess

Status: test
Severity: high
Log source: category process_creation, product windows
Author: Florian Roth (Nextron Systems), Maxime Thiebaut
Source: github.com/SigmaHQ/sigma

Detects a explorer.exe sub process of the RazerInstaller software which can be invoked from the installer to select a different installation folder but can also be exploited to escalate privileges to LOCAL SYSTEM

Known false positives

User selecting a different installation folder (check for other sub processes of this explorer.exe process)

MITRE ATT&CK coverage

Tactic	Techniques
Defense Impairment	`T1553` Subvert Trust Controls

Telemetry coverage

Provider	Record / event type
Sysmon	Event ID 1: Process creation
Security-Auditing	Event ID 4688: A new process has been created.

Rule body

title: Suspicious RazerInstaller Explorer Subprocess
id: a4eaf250-7dc1-4842-862a-5e71cd59a167
status: test
description: Detects a explorer.exe sub process of the RazerInstaller software which can be invoked from the installer to select a different installation folder but can also be exploited to escalate privileges to LOCAL SYSTEM
references:
    - https://twitter.com/j0nh4t/status/1429049506021138437
    - https://streamable.com/q2dsji
author: Florian Roth (Nextron Systems), Maxime Thiebaut
date: 2021-08-23
modified: 2024-12-01
tags:
    - attack.privilege-escalation
    - attack.defense-impairment
    - attack.t1553
    - detection.emerging-threats
logsource:
    category: process_creation
    product: windows
detection:
    selection:
        ParentImage|endswith: '\RazerInstaller.exe'
        IntegrityLevel:
            - 'System'
            - 'S-1-16-16384' # System
    filter_main_razer:
        Image|startswith: 'C:\Windows\Installer\Razer\Installer\'
    condition: selection and not 1 of filter_main_*
falsepositives:
    - User selecting a different installation folder (check for other sub processes of this explorer.exe process)
level: high

Stages and Predicates

Stage 0: `condition`

selection and not 1 of filter_main_*

Stage 1: `selection`

selection:
    ParentImage|endswith: '\RazerInstaller.exe'
    IntegrityLevel:
        - 'System'
        - 'S-1-16-16384'

Stage 2: `not filter_main_razer`

filter_main_razer:
    Image|startswith: 'C:\Windows\Installer\Razer\Installer\'

Exclusions

The rule actively suppresses these predicates.

Field	Kind	Excluded values	Search
`Image`	starts_with	`C:\Windows\Installer\Razer\Installer\`	`excludes:Image` `field:"Image" value:"C:\Windows\Installer\Razer\Installer\"`

Indicators

These rows show field, operator, and value matches.

Field	Kind	Values	Search
`IntegrityLevel`	eq	`S-1-16-16384` corpus 30 (sigma 22, splunk 4, elastic 3, kusto 1) `System` corpus 30 (sigma 22, splunk 4, elastic 3, kusto 1)	`field:"IntegrityLevel" kind:eq`
`ParentImage`	ends_with	`\RazerInstaller.exe`	`field:"ParentImage" kind:ends_with value:"\RazerInstaller.exe"`