Threat Huntmediumtest

Suspicious New Instance Of An Office COM Object

Detects an svchost process spawning an instance of an office application. This happens when the initial word application creates an instance of one of the Office COM objects such as 'Word.Application', 'Excel.Application', etc. This can be used by malicious actors to create malicious Office documents with macros on the fly. (See vba2clr project in the references)

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Launch

Nasreddine Bencherchali (Nextron Systems)Created Thu Oct 13Updated Tue Dec 199bdaf1e9-fdef-443b-8081-4341b74a7e28windows

Hunting Hypothesis

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:
        ParentImage|endswith: '\svchost.exe'
        Image|endswith:
            - '\eqnedt32.exe'
            - '\excel.exe'
            - '\msaccess.exe'
            - '\mspub.exe'
            - '\powerpnt.exe'
            - '\visio.exe'
            - '\winword.exe'
    condition: selection