UAC Bypass via ICMLuaUtil

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

Detects the pattern of UAC Bypass using ICMLuaUtil Elevated COM interface

MITRE ATT&CK coverage

Tactic	Techniques
Privilege Escalation	`T1548.002` Abuse Elevation Control Mechanism: Bypass User Account Control

Telemetry coverage

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

Rule body

title: UAC Bypass via ICMLuaUtil
id: 49f2f17b-b4c8-4172-a68b-d5bf95d05130
status: test
description: Detects the pattern of UAC Bypass using ICMLuaUtil Elevated COM interface
references:
    - https://www.elastic.co/guide/en/security/current/uac-bypass-via-icmluautil-elevated-com-interface.html
author: Florian Roth (Nextron Systems), Elastic (idea)
date: 2022-09-13
modified: 2022-09-27
tags:
    - attack.privilege-escalation
    - attack.t1548.002
logsource:
    category: process_creation
    product: windows
detection:
    selection:
        ParentImage|endswith: '\dllhost.exe'
        ParentCommandLine|contains:
            - '/Processid:{3E5FC7F9-9A51-4367-9063-A120244FBEC7}'
            - '/Processid:{D2E7041B-2927-42FB-8E9F-7CE93B6DC937}'
    filter:
        - Image|endswith: '\WerFault.exe'
        - OriginalFileName: 'WerFault.exe'
    condition: selection and not filter
falsepositives:
    - Unknown
level: high

Stages and Predicates

Stage 0: `condition`

selection and not filter

Stage 1: `selection`

selection:
    ParentImage|endswith: '\dllhost.exe'
    ParentCommandLine|contains:
        - '/Processid:{3E5FC7F9-9A51-4367-9063-A120244FBEC7}'
        - '/Processid:{D2E7041B-2927-42FB-8E9F-7CE93B6DC937}'

Stage 2: `not filter`

filter:
    - Image|endswith: '\WerFault.exe'
    - OriginalFileName: '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"`
`OriginalFileName`	eq	`WerFault.exe`	`excludes:OriginalFileName` `field:"OriginalFileName" value:"WerFault.exe"`

Indicators

These rows show field, operator, and value matches.

Field	Kind	Values	Search
`ParentCommandLine`	match	`/Processid:{3E5FC7F9-9A51-4367-9063-A120244FBEC7}` `/Processid:{D2E7041B-2927-42FB-8E9F-7CE93B6DC937}`	`field:"ParentCommandLine" kind:match`
`ParentImage`	ends_with	`\dllhost.exe` corpus 7 (sigma 7)	`field:"ParentImage" kind:ends_with value:"\dllhost.exe"`

UAC Bypass via ICMLuaUtil

MITRE ATT&CK coverage

Telemetry coverage

Rule body

Stages and Predicates

Stage 0: condition

Stage 1: selection

Stage 2: not filter

Exclusions

Indicators

Stage 0: `condition`

Stage 1: `selection`

Stage 2: `not filter`