Suspicious Child Process Of BgInfo.EXE

SIGMA detection rule by Nasreddine Bencherchali (Nextron Systems) · GPL-2.0

Detects suspicious child processes of "BgInfo.exe" which could be a sign of potential abuse of the binary to proxy execution via external VBScript

title: Suspicious Child Process Of BgInfo.EXE
id: c5a82926-ad38-8cac-850a-dcc4d26f5660
related:
    - id: aaf46cdc-934e-4284-b329-34aa701e3771
      type: similar
    - id: 811f459f-9231-45d4-959a-0266c6311987
      type: derived
status: test
description: Detects suspicious child processes of "BgInfo.exe" which could be a sign of potential abuse of the binary to proxy execution via external VBScript
references:
    - https://lolbas-project.github.io/lolbas/OtherMSBinaries/Bginfo/
    - https://oddvar.moe/2017/05/18/bypassing-application-whitelisting-with-bginfo/
author: Nasreddine Bencherchali (Nextron Systems)
date: 2023-08-16
tags:
    - attack.execution
    - attack.stealth
    - attack.t1059.005
    - attack.t1218
    - attack.t1202
logsource:
    category: process_creation
    product: windows
detection:
    process_creation:
        EventID: 4688
        Channel: Security
    selection_parent:
        ParentProcessName|endswith:
            - \bginfo.exe
            - \bginfo64.exe
    selection_child:
        - NewProcessName|endswith:
              - \calc.exe
              - \cmd.exe
              - \cscript.exe
              - \mshta.exe
              - \notepad.exe
              - \powershell.exe
              - \pwsh.exe
              - \wscript.exe
        - NewProcessName|contains:
              - \AppData\Local\
              - \AppData\Roaming\
              - :\Users\Public\
              - :\Temp\
              - :\Windows\Temp\
              - :\PerfLogs\
    condition: process_creation and (all of selection_*)
falsepositives:
    - Unknown
level: high
ruletype: Sigma

[[ currentRule.title && currentRule.title.length > 60 ? currentRule.title.slice(0, 60) + '…' : currentRule.title ]]

d1a2e079-1e93-4f63-a991-d035ee430b8b

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Executable code, not a declarative rule

This submission is arbitrary [[ currentRule.format ? currentRule.format.toUpperCase() : '' ]] code, not a declarative detection rule — review it as you would any script before running it, and note that it cannot be safely aggregated or auto-executed alongside YARA/Sigma/Suricata/CRS rules.

Rejected pattern present

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Format & documentation suggestions

Not a security issue — this rule is valid and was accepted as-is. These are optional fields/conventions its own format recommends, mainly affecting its quality score and how well it documents itself for other reviewers.

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