Detectionhightest

Suspicious AddinUtil.EXE CommandLine Execution

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.

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Launch

Nasreddine Bencherchali (Nextron Systems), Michael McKinley, Tony LatteriCreated Mon Sep 18631b22a4-70f4-4e2f-9ea8-42f84d9df6d8windows

Log Source

WindowsProcess Creation

ProductWindows← raw: windows

CategoryProcess Creation← raw: process_creation

Events generated when a new process is spawned on the system. Covers command-line arguments, parent/child relationships, and process metadata.

Detection Logic

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)