Detection rules › Sigma

Potentially Suspicious GoogleUpdate Child Process

Status
test
Severity
high
Log source
category process_creation, product windows
Author
Nasreddine Bencherchali (Nextron Systems)
Source
github.com/SigmaHQ/sigma

Detects potentially suspicious child processes of "GoogleUpdate.exe"

MITRE ATT&CK coverage

TacticTechniques
StealthNo specific technique

Telemetry coverage

Rule body

title: Potentially Suspicious GoogleUpdate Child Process
id: 84b1ecf9-6eff-4004-bafb-bae5c0e251b2
related:
    - id: bdbab15a-3826-48fa-a1b7-723cd8f32fcc
      type: derived
status: test
description: Detects potentially suspicious child processes of "GoogleUpdate.exe"
references:
    - https://www.ncsc.gov.uk/static-assets/documents/malware-analysis-reports/goofy-guineapig/NCSC-MAR-Goofy-Guineapig.pdf
author: Nasreddine Bencherchali (Nextron Systems)
date: 2023-05-15
modified: 2023-05-22
tags:
    - attack.stealth
logsource:
    category: process_creation
    product: windows
detection:
    selection:
        ParentImage|endswith: '\GoogleUpdate.exe'
    filter_main_known_legit:
        # Some other legit child process might exist. It's better to make a baseline before running this in production
        - Image|contains: '\Google' # Example: GoogleUpdate.exe, GoogleCrashHandler.exe, GoogleUpdateComRegisterShell64.exe
        - Image|endswith:
              - '\setup.exe'
              - 'chrome_updater.exe'
              - 'chrome_installer.exe'
    filter_main_image_null:
        Image: null
    condition: selection and not 1 of filter_main_*
falsepositives:
    - Unknown
level: high

Stages and Predicates

Stage 0: condition

selection and not 1 of filter_main_*

Stage 1: selection

selection:
    ParentImage|endswith: '\GoogleUpdate.exe'

Stage 2: not filter_main_*

filter_main_known_legit:
    - Image|contains: '\Google'
    - Image|endswith:
          - '\setup.exe'
          - 'chrome_updater.exe'
          - 'chrome_installer.exe'
filter_main_image_null:
    Image: null

Exclusions

The rule actively suppresses these predicates.

FieldKindExcluded valuesSearch
Imageends_with\setup.exeexcludes:Image field:"Image" value:"\setup.exe"
Imageends_withchrome_installer.exeexcludes:Image field:"Image" value:"chrome_installer.exe"
Imageends_withchrome_updater.exeexcludes:Image field:"Image" value:"chrome_updater.exe"
Imageis_null(no value, null check)excludes:Image
Imagematch\Googleexcludes:Image field:"Image" value:"\Google"

Indicators

These rows show field, operator, and value matches.

FieldKindValuesSearch
ParentImageends_with
  • \GoogleUpdate.exe corpus 3 (sigma 3)
field:"ParentImage" kind:ends_with value:"\GoogleUpdate.exe"