Suspicious Child Process Of BgInfo.EXE — Sigma Rule

Rule metadata and linked tags

Author: Nasreddine Bencherchali (Nextron Systems). Source status: test; severity: high. Source dates: 2023-08-16 / not supplied.

{
  "category": "process_creation",
  "product": "windows"
}

Pinned original Sigma rule · Detection Rule License 1.1

Source SHA-256: 9726c15d3ec2b113f08e301b222aa33f442cc51da9cff325eb937d5b687fe149

Detection logic

Original source YAML. Source-tag agreement is not proof of complete semantic coverage. This rule has not been compiled for a SIEM backend or validated against live telemetry here.

title: Suspicious Child Process Of BgInfo.EXE
id: 811f459f-9231-45d4-959a-0266c6311987
related:
    - id: aaf46cdc-934e-4284-b329-34aa701e3771
      type: similar
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:
    selection_parent:
        ParentImage|endswith:
            - '\bginfo.exe'
            - '\bginfo64.exe'
    selection_child:
        - Image|endswith:
              - '\calc.exe'
              - '\cmd.exe'
              - '\cscript.exe'
              - '\mshta.exe'
              - '\notepad.exe'
              - '\powershell.exe'
              - '\pwsh.exe'
              - '\wscript.exe'
        - Image|contains:
              - '\AppData\Local\'
              - '\AppData\Roaming\'
              - ':\Users\Public\'
              - ':\Temp\'
              - ':\Windows\Temp\'
              - ':\PerfLogs\'
    condition: all of selection_*
falsepositives:
    - Unknown
level: high

Original YAML and metadata in JSON

False positives

• Unknown

Source references

• https://lolbas-project.github.io/lolbas/OtherMSBinaries/Bginfo/
• https://oddvar.moe/2017/05/18/bypassing-application-whitelisting-with-bginfo/