UAC Bypass via Windows Firewall Snap-In Hijack

Status: test
Severity: medium
Log source: category process_creation, product windows
Author: Tim Rauch, Elastic (idea)
Source: github.com/SigmaHQ/sigma

Detects attempts to bypass User Account Control (UAC) by hijacking the Microsoft Management Console (MMC) Windows Firewall snap-in

MITRE ATT&CK coverage

Tactic	Techniques
Privilege Escalation	`T1548` Abuse Elevation Control Mechanism

Telemetry coverage

Provider	Record / event type
Sysmon	Event ID 1: Process creation

Rule body

title: UAC Bypass via Windows Firewall Snap-In Hijack
id: e52cb31c-10ed-4aea-bcb7-593c9f4a315b
status: test
description: Detects attempts to bypass User Account Control (UAC) by hijacking the Microsoft Management Console (MMC) Windows Firewall snap-in
references:
    - https://www.elastic.co/guide/en/security/current/uac-bypass-via-windows-firewall-snap-in-hijack.html#uac-bypass-via-windows-firewall-snap-in-hijack
author: Tim Rauch, Elastic (idea)
date: 2022-09-27
tags:
    - attack.privilege-escalation
    - attack.t1548
logsource:
    category: process_creation
    product: windows
detection:
    selection:
        ParentImage|endswith: '\mmc.exe'
        ParentCommandLine|contains: 'WF.msc'
    filter:
        Image|endswith: '\WerFault.exe'
    condition: selection and not filter
falsepositives:
    - Unknown
level: medium

Stages and Predicates

Stage 0: `condition`

selection and not filter

Stage 1: `selection`

selection:
    ParentImage|endswith: '\mmc.exe'
    ParentCommandLine|contains: 'WF.msc'

Stage 2: `not filter`

filter:
    Image|endswith: '\WerFault.exe'

Exclusions

The rule actively suppresses these predicates.

Field	Kind	Excluded values	Search
`Image`	ends_with	`\WerFault.exe`	`excludes:Image` `field:"Image" value:"\WerFault.exe"`

Indicators

These rows show field, operator, and value matches.

Field	Kind	Values	Search
`ParentCommandLine`	match	`WF.msc`	`field:"ParentCommandLine" kind:match value:"WF.msc"`
`ParentImage`	ends_with	`\mmc.exe` corpus 3 (sigma 3)	`field:"ParentImage" kind:ends_with value:"\mmc.exe"`