Potential Arbitrary File Download Using Office Application — Sigma Rule

Rule metadata and linked tags

Author: Nasreddine Bencherchali (Nextron Systems), Beyu Denis, oscd.community. Source status: test; severity: high. Source dates: 2022-05-17 / 2023-06-22.

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

Pinned original Sigma rule · Detection Rule License 1.1

Source SHA-256: a39760c54ac4383232160b337eacc5882f9fc34345b2d4a10557fa176edbf8a7

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 Arbitrary File Download Using Office Application
id: 4ae3e30b-b03f-43aa-87e3-b622f4048eed
related:
    - id: 0c79148b-118e-472b-bdb7-9b57b444cc19
      type: obsolete
status: test
description: Detects potential arbitrary file download using a Microsoft Office application
references:
    - https://lolbas-project.github.io/lolbas/OtherMSBinaries/Winword/
    - https://lolbas-project.github.io/lolbas/OtherMSBinaries/Powerpnt/
    - https://lolbas-project.github.io/lolbas/OtherMSBinaries/Excel/
    - https://medium.com/@reegun/unsanitized-file-validation-leads-to-malicious-payload-download-via-office-binaries-202d02db7191
author: Nasreddine Bencherchali (Nextron Systems), Beyu Denis, oscd.community
date: 2022-05-17
modified: 2023-06-22
tags:
    - attack.stealth
    - attack.t1202
logsource:
    category: process_creation
    product: windows
detection:
    selection_img:
        - Image|endswith:
              - '\EXCEL.EXE'
              - '\POWERPNT.EXE'
              - '\WINWORD.exe'
        - OriginalFileName:
              - 'Excel.exe'
              - 'POWERPNT.EXE'
              - 'WinWord.exe'
    selection_http:
        CommandLine|contains:
            - 'http://'
            - 'https://'
    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/Winword/
• https://lolbas-project.github.io/lolbas/OtherMSBinaries/Powerpnt/
• https://lolbas-project.github.io/lolbas/OtherMSBinaries/Excel/
• https://medium.com/@reegun/unsanitized-file-validation-leads-to-malicious-payload-download-via-office-binaries-202d02db7191