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Detection rules › Sigma

UAC Bypass Using EventVwr

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

Detects the pattern of a UAC bypass using Windows Event Viewer

MITRE ATT&CK coverage

TacticTechniques
Privilege EscalationNo specific technique
StealthNo specific technique

Event coverage

ProviderEventTitle
SysmonEvent ID 11FileCreate

Rule body yaml

title: UAC Bypass Using EventVwr
id: 63e4f530-65dc-49cc-8f80-ccfa95c69d43
status: test
description: Detects the pattern of a UAC bypass using Windows Event Viewer
references:
    - https://twitter.com/orange_8361/status/1518970259868626944?s=20&t=RFXqZjtA7tWM3HxqEH78Aw
    - https://twitter.com/splinter_code/status/1519075134296006662?s=12&t=DLUXH86WtcmG_AZ5gY3C6g
    - https://lolbas-project.github.io/lolbas/Binaries/Eventvwr/#execute
author: Antonio Cocomazzi (idea), Florian Roth (Nextron Systems)
date: 2022-04-27
modified: 2022-11-22
tags:
    - attack.privilege-escalation
    - attack.stealth
logsource:
    category: file_event
    product: windows
detection:
    selection:
        TargetFilename|endswith:
            # Removed the start just in case the logging backend doesn't expand ENV variables when they're used
            - '\Microsoft\Event Viewer\RecentViews'
            - '\Microsoft\EventV~1\RecentViews'
    filter:
        Image|startswith:
            - 'C:\Windows\System32\'
            - 'C:\Windows\SysWOW64\'
    condition: selection and not filter
falsepositives:
    - Unknown
level: high

Stages and Predicates

Stage 0: condition

selection and not filter

Stage 1: selection

selection:
    TargetFilename|endswith:
        - '\Microsoft\Event Viewer\RecentViews'
        - '\Microsoft\EventV~1\RecentViews'

Stage 2: not filter

filter:
    Image|startswith:
        - 'C:\Windows\System32\'
        - 'C:\Windows\SysWOW64\'

Exclusions

Top-level NOT(...) conjuncts: predicates this rule actively suppresses.

FieldKindExcluded values
Imagestarts_withC:\Windows\SysWOW64\
Imagestarts_withC:\Windows\System32\

Indicators

Each row is a field, operator, and value that the rule matches. The corpus column counts how many other rules in the catalog look for the same combination: high numbers point to widely-used, community-vetted indicators. Blank or 1 shows that the indicator is specific to this rule.

FieldKindValues
TargetFilenameends_with
  • \Microsoft\Event Viewer\RecentViews
  • \Microsoft\EventV~1\RecentViews