Microsoft Office DLL Sideload — Sigma Rule

Rule metadata and linked tags

Author: Nasreddine Bencherchali (Nextron Systems), Wietze Beukema (project and research). Source status: test; severity: high. Source dates: 2022-08-17 / 2023-03-15.

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

Pinned original Sigma rule · Detection Rule License 1.1

Source SHA-256: 81818d92e060f7de1d29d6a68b446d864c84f2d33f684c8c1d779b17107985b6

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: Microsoft Office DLL Sideload
id: 829a3bdf-34da-4051-9cf4-8ed221a8ae4f
status: test
description: Detects DLL sideloading of DLLs that are part of Microsoft Office from non standard location
references:
    - https://hijacklibs.net/ # For list of DLLs that could be sideloaded (search for dlls mentioned here in there)
author: Nasreddine Bencherchali (Nextron Systems), Wietze Beukema (project and research)
date: 2022-08-17
modified: 2023-03-15
tags:
    - attack.persistence
    - attack.privilege-escalation
    - attack.execution
    - attack.stealth
    - attack.t1574.001
logsource:
    category: image_load
    product: windows
detection:
    selection:
        ImageLoaded|endswith: '\outllib.dll'
    filter:
        ImageLoaded|startswith:
            - 'C:\Program Files\Microsoft Office\OFFICE'
            - 'C:\Program Files (x86)\Microsoft Office\OFFICE'
            - 'C:\Program Files\Microsoft Office\Root\OFFICE'
            - 'C:\Program Files (x86)\Microsoft Office\Root\OFFICE'
    condition: selection and not filter
falsepositives:
    - Unlikely
level: high

Original YAML and metadata in JSON

False positives

• Unlikely

Source references

• https://hijacklibs.net/