Detection rules › Sigma

DotNET Assembly DLL Loaded Via Office Application

Status
test
Severity
medium
Log source
category image_load, product windows
Author
Antonlovesdnb
Source
github.com/SigmaHQ/sigma

Detects any assembly DLL being loaded by an Office Product

MITRE ATT&CK coverage

Telemetry coverage

ProviderRecord / event type
SysmonEvent ID 7: Image loaded

Rule body

title: DotNET Assembly DLL Loaded Via Office Application
id: ff0f2b05-09db-4095-b96d-1b75ca24894a
status: test
description: Detects any assembly DLL being loaded by an Office Product
references:
    - https://medium.com/threatpunter/detecting-adversary-tradecraft-with-image-load-event-logging-and-eql-8de93338c16
author: Antonlovesdnb
date: 2020-02-19
modified: 2023-03-29
tags:
    - attack.execution
    - attack.t1204.002
logsource:
    category: image_load
    product: windows
detection:
    selection:
        Image|endswith:
            - '\excel.exe'
            - '\mspub.exe'
            - '\onenote.exe'
            - '\onenoteim.exe' # Just in case
            - '\outlook.exe'
            - '\powerpnt.exe'
            - '\winword.exe'
        ImageLoaded|startswith: 'C:\Windows\assembly\'
    condition: selection
falsepositives:
    - Unknown
level: medium

Stages and Predicates

Stage 0: condition

selection

Stage 1: selection

selection:
    Image|endswith:
        - '\excel.exe'
        - '\mspub.exe'
        - '\onenote.exe'
        - '\onenoteim.exe'
        - '\outlook.exe'
        - '\powerpnt.exe'
        - '\winword.exe'
    ImageLoaded|startswith: 'C:\Windows\assembly\'

Indicators

These rows show field, operator, and value matches.

FieldKindValuesSearch
Imageends_with
  • \excel.exe corpus 16 (sigma 16)
  • \mspub.exe corpus 10 (sigma 10)
  • \onenote.exe corpus 6 (sigma 6)
  • \onenoteim.exe corpus 6 (sigma 6)
  • \outlook.exe corpus 13 (sigma 13)
  • \powerpnt.exe corpus 14 (sigma 14)
  • \winword.exe corpus 17 (sigma 17)
field:"Image" kind:ends_with
ImageLoadedstarts_with
  • C:\Windows\assembly\
field:"ImageLoaded" kind:starts_with value:"C:\Windows\assembly\"