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Detection rules › Sigma

UAC Bypass Using NTFS Reparse Point - File

Status
test
Severity
high
Log source
category file_event, product windows
Author
Christian Burkard (Nextron Systems)
Source
github.com/SigmaHQ/sigma

Detects the pattern of UAC Bypass using NTFS reparse point and wusa.exe DLL hijacking (UACMe 36)

MITRE ATT&CK coverage

TacticTechniques
Privilege Escalation

Telemetry coverage

ProviderRecord / event type
SysmonEvent ID 11: FileCreate

Rule body

title: UAC Bypass Using NTFS Reparse Point - File
id: 7fff6773-2baa-46de-a24a-b6eec1aba2d1
status: test
description: Detects the pattern of UAC Bypass using NTFS reparse point and wusa.exe DLL hijacking (UACMe 36)
references:
    - https://github.com/hfiref0x/UACME
author: Christian Burkard (Nextron Systems)
date: 2021-08-30
modified: 2022-10-09
tags:
    - attack.privilege-escalation
    - attack.t1548.002
logsource:
    category: file_event
    product: windows
detection:
    selection:
        TargetFilename|startswith: 'C:\Users\'
        TargetFilename|endswith: '\AppData\Local\Temp\api-ms-win-core-kernel32-legacy-l1.DLL'
    condition: selection
falsepositives:
    - Unknown
level: high

Stages and Predicates

Stage 0: condition

selection

Stage 1: selection

selection:
    TargetFilename|startswith: 'C:\Users\'
    TargetFilename|endswith: '\AppData\Local\Temp\api-ms-win-core-kernel32-legacy-l1.DLL'

Indicators

These rows show field, operator, and value matches.

FieldKindValuesSearch
TargetFilenameends_with
  • \AppData\Local\Temp\api-ms-win-core-kernel32-legacy-l1.DLL
field:"TargetFilename" kind:ends_with value:"\AppData\Local\Temp\api-ms-win-core-kernel32-legacy-l1.DLL"
TargetFilenamestarts_with
  • C:\Users\ corpus 13 (sigma 9, elastic 4)
field:"TargetFilename" kind:starts_with value:"C:\Users\"