Suspicious AddinUtil.EXE CommandLine Execution

title: Suspicious AddinUtil.EXE CommandLine Execution
id: 631b22a4-70f4-4e2f-9ea8-42f84d9df6d8
status: test
description: |
    Detects execution of the Add-In deployment cache updating utility (AddInutil.exe) with suspicious Addinroot or Pipelineroot paths. An adversary may execute AddinUtil.exe with uncommon Addinroot/Pipelineroot paths that point to the adversaries Addins.Store payload.
references:
    - https://www.blue-prints.blog/content/blog/posts/lolbin/addinutil-lolbas.html
author: Nasreddine Bencherchali (Nextron Systems), Michael McKinley (@McKinleyMike), Tony Latteri (@TheLatteri)
date: 2023-09-18
tags:
    - attack.defense-evasion
    - attack.t1218
logsource:
    category: process_creation
    product: windows
detection:
    selection_img:
        - Image|endswith: '\addinutil.exe'
        - OriginalFileName: 'AddInUtil.exe'
    selection_susp_1_flags:
        CommandLine|contains:
            - '-AddInRoot:'
            - '-PipelineRoot:'
    selection_susp_1_paths:
        CommandLine|contains:
            - '\AppData\Local\Temp\'
            - '\Desktop\'
            - '\Downloads\'
            - '\Users\Public\'
            - '\Windows\Temp\'
    selection_susp_2:
        CommandLine|contains:
            - '-AddInRoot:.'
            - '-AddInRoot:"."'
            - '-PipelineRoot:.'
            - '-PipelineRoot:"."'
        CurrentDirectory|contains:
            - '\AppData\Local\Temp\'
            - '\Desktop\'
            - '\Downloads\'
            - '\Users\Public\'
            - '\Windows\Temp\'
    condition: selection_img and (all of selection_susp_1_* or selection_susp_2)
falsepositives:
    - Unknown
level: high