Potentially Suspicious Execution From Parent Process In Public Folder — Sigma Rule

Rule metadata and linked tags

Author: Florian Roth (Nextron Systems), Nasreddine Bencherchali (Nextron Systems). Source status: test; severity: high. Source dates: 2022-02-25 / 2024-07-12.

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

Pinned original Sigma rule · Detection Rule License 1.1

Source SHA-256: cbb3f8d69aae01fb7d80c8fae40bfc4ceeff20329e4ed0a01e6a231da8469eed

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: Potentially Suspicious Execution From Parent Process In Public Folder
id: 69bd9b97-2be2-41b6-9816-fb08757a4d1a
status: test
description: |
    Detects a potentially suspicious execution of a parent process located in the "\Users\Public" folder executing a child process containing references to shell or scripting binaries and commandlines.
references:
    - https://redcanary.com/blog/blackbyte-ransomware/
author: Florian Roth (Nextron Systems), Nasreddine Bencherchali (Nextron Systems)
date: 2022-02-25
modified: 2024-07-12
tags:
    - attack.execution
    - attack.stealth
    - attack.t1564
    - attack.t1059
logsource:
    category: process_creation
    product: windows
detection:
    selection_parent:
        ParentImage|contains: ':\Users\Public\'
    selection_child:
        - Image|endswith:
              - '\bitsadmin.exe'
              - '\certutil.exe'
              - '\cmd.exe'
              - '\cscript.exe'
              - '\mshta.exe'
              - '\powershell.exe'
              - '\pwsh.exe'
              - '\regsvr32.exe'
              - '\rundll32.exe'
              - '\wscript.exe'
        - CommandLine|contains:
              - 'bitsadmin'
              - 'certutil'
              - 'cscript'
              - 'mshta'
              - 'powershell'
              - 'regsvr32'
              - 'rundll32'
              - 'wscript'
    condition: all of selection_*
falsepositives:
    - Unknown
level: high

Original YAML and metadata in JSON

False positives

• Unknown

Source references

• https://redcanary.com/blog/blackbyte-ransomware/