Detection rules › Sigma
Microsoft Office DLL Sideload
Detects DLL sideloading of DLLs that are part of Microsoft Office from non standard location
MITRE ATT&CK coverage
| Tactic | Techniques |
|---|---|
| Execution | T1574.001 Hijack Execution Flow: DLL |
| Stealth | T1574.001 Hijack Execution Flow: DLL |
Event coverage
| Provider | Event | Title |
|---|---|---|
| Sysmon | Event ID 7 | Image loaded |
Rule body yaml
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
Stages and Predicates
Stage 0: condition
selection and not filterStage 1: selection
selection:
ImageLoaded|endswith: '\outllib.dll'
Stage 2: not filter
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'
Exclusions
Top-level NOT(...) conjuncts: predicates this rule actively suppresses.
| Field | Kind | Excluded values |
|---|---|---|
ImageLoaded | starts_with | C:\Program Files (x86)\Microsoft Office\OFFICE |
ImageLoaded | starts_with | C:\Program Files (x86)\Microsoft Office\Root\OFFICE |
ImageLoaded | starts_with | C:\Program Files\Microsoft Office\OFFICE |
ImageLoaded | starts_with | C:\Program Files\Microsoft Office\Root\OFFICE |
Indicators
Each row is a field, operator, and value that the rule matches. The corpus column counts how many other rules in the catalog look for the same combination: high numbers point to widely-used, community-vetted indicators. Blank or 1 shows that the indicator is specific to this rule.
| Field | Kind | Values |
|---|---|---|
ImageLoaded | ends_with |
|