Potential DLL Sideloading Via JsSchHlp — Sigma Rule

Rule metadata and linked tags

Author: frack113. Source status: test; severity: medium. Source dates: 2022-12-14 / not supplied.

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

Pinned original Sigma rule · Detection Rule License 1.1

Source SHA-256: 2db7168ad538398afc19f3a2c052348bb7228e81a751f799971a2a18ee3d6b2d

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: Potential DLL Sideloading Via JsSchHlp
id: 68654bf0-4412-43d5-bfe8-5eaa393cd939
status: test
description: Detects potential DLL sideloading using JUSTSYSTEMS Japanese word processor
references:
    - https://www.welivesecurity.com/2022/12/14/unmasking-mirrorface-operation-liberalface-targeting-japanese-political-entities/
    - http://www.windowexe.com/bbs/board.php?q=jsschhlp-exe-c-program-files-common-files-justsystem-jsschhlp-jsschhlp
author: frack113
date: 2022-12-14
tags:
    - attack.persistence
    - attack.privilege-escalation
    - attack.execution
    - attack.stealth
    - attack.t1574.001
logsource:
    category: image_load
    product: windows
detection:
    selection:
        ImageLoaded|endswith: '\JSESPR.dll'
    filter:
        ImageLoaded|startswith: 'C:\Program Files\Common Files\Justsystem\JsSchHlp\'
    condition: selection and not filter
falsepositives:
    - Unknown
level: medium

Original YAML and metadata in JSON

False positives

• Unknown

Source references

• https://www.welivesecurity.com/2022/12/14/unmasking-mirrorface-operation-liberalface-targeting-japanese-political-entities/
• http://www.windowexe.com/bbs/board.php?q=jsschhlp-exe-c-program-files-common-files-justsystem-jsschhlp-jsschhlp