Suspicious Binary In User Directory Spawned From Office Application — Sigma Rule

Rule metadata and linked tags

Author: Jason Lynch. Source status: test; severity: high. Source dates: 2019-04-02 / 2023-02-04.

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

Pinned original Sigma rule · Detection Rule License 1.1

Source SHA-256: 0ed895a7f7b19049f40f6e208730e072eaac658f6ee3578fa240395da8dcf86b

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 Binary In User Directory Spawned From Office Application
id: aa3a6f94-890e-4e22-b634-ffdfd54792cc
status: test
description: Detects an executable in the users directory started from one of the Microsoft Office suite applications (Word, Excel, PowerPoint, Publisher, Visio)
references:
    - https://blog.morphisec.com/fin7-not-finished-morphisec-spots-new-campaign
    - https://www.virustotal.com/gui/file/23160972c6ae07f740800fa28e421a81d7c0ca5d5cab95bc082b4a986fbac57
author: Jason Lynch
date: 2019-04-02
modified: 2023-02-04
tags:
    - attack.execution
    - attack.t1204.002
    - attack.g0046
    - car.2013-05-002
logsource:
    category: process_creation
    product: windows
detection:
    selection:
        ParentImage|endswith:
            - '\WINWORD.EXE'
            - '\EXCEL.EXE'
            - '\POWERPNT.exe'
            - '\MSPUB.exe'
            - '\VISIO.exe'
            - '\MSACCESS.exe'
            - '\EQNEDT32.exe'
            # - '\OUTLOOK.EXE' too many FPs
        Image|startswith: 'C:\users\'
        Image|endswith: '.exe'
    filter:
        Image|endswith: '\Teams.exe'
    condition: selection and not filter
falsepositives:
    - Unknown
level: high

Original YAML and metadata in JSON

False positives

• Unknown

Source references

• https://blog.morphisec.com/fin7-not-finished-morphisec-spots-new-campaign
• https://www.virustotal.com/gui/file/23160972c6ae07f740800fa28e421a81d7c0ca5d5cab95bc082b4a986fbac57