Detectionhightest

Suspicious Microsoft Office Child Process

Detects a suspicious process spawning from one of the Microsoft Office suite products (Word, Excel, PowerPoint, Publisher, Visio, etc.)

Convert In Phoenix Studio

Open this Sigma rule in the converter with the YAML preloaded and ready for backend selection.

Launch
Florian Roth (Nextron Systems), Markus Neis, FPT.EagleEye Team, Vadim Khrykov, Cyb3rEng, Michael Haag, Christopher Peacock, SCYTHECreated Fri Apr 06Updated Mon Apr 24438025f9-5856-4663-83f7-52f878a70a50windows
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 Logic3 selectors
detection:
    selection_parent:
        ParentImage|endswith:
            - '\EQNEDT32.EXE'
            - '\EXCEL.EXE'
            - '\MSACCESS.EXE'
            - '\MSPUB.exe'
            - '\ONENOTE.EXE'
            - '\POWERPNT.exe'
            - '\VISIO.exe'
            - '\WINWORD.EXE'
            - '\wordpad.exe'
            - '\wordview.exe'
    selection_child_processes:
        - OriginalFileName:
              - 'bitsadmin.exe'
              - 'CertOC.exe'
              - 'CertUtil.exe'
              - 'Cmd.Exe'
              - 'CMSTP.EXE'
              - 'cscript.exe'
              - 'curl.exe'
              - 'HH.exe'
              - 'IEExec.exe'
              - 'InstallUtil.exe'
              - 'javaw.exe'
              - 'Microsoft.Workflow.Compiler.exe'
              - 'msdt.exe'
              - 'MSHTA.EXE'
              - 'msiexec.exe'
              - 'Msxsl.exe'
              - 'odbcconf.exe'
              - 'pcalua.exe'
              - 'PowerShell.EXE'
              - 'RegAsm.exe'
              - 'RegSvcs.exe'
              - 'REGSVR32.exe'
              - 'RUNDLL32.exe'
              - 'schtasks.exe'
              - 'ScriptRunner.exe'
              - 'wmic.exe'
              - 'WorkFolders.exe'
              - 'wscript.exe'
        - Image|endswith:
              - '\AppVLP.exe'
              - '\bash.exe'
              - '\bitsadmin.exe'
              - '\certoc.exe'
              - '\certutil.exe'
              - '\cmd.exe'
              - '\cmstp.exe'
              - '\control.exe'
              - '\cscript.exe'
              - '\curl.exe'
              - '\forfiles.exe'
              - '\hh.exe'
              - '\ieexec.exe'
              - '\installutil.exe'
              - '\javaw.exe'
              - '\mftrace.exe'
              - '\Microsoft.Workflow.Compiler.exe'
              - '\msbuild.exe'
              - '\msdt.exe'
              - '\mshta.exe'
              - '\msidb.exe'
              - '\msiexec.exe'
              - '\msxsl.exe'
              - '\odbcconf.exe'
              - '\pcalua.exe'
              - '\powershell.exe'
              - '\pwsh.exe'
              - '\regasm.exe'
              - '\regsvcs.exe'
              - '\regsvr32.exe'
              - '\rundll32.exe'
              - '\schtasks.exe'
              - '\scrcons.exe'
              - '\scriptrunner.exe'
              - '\sh.exe'
              - '\svchost.exe'
              - '\verclsid.exe'
              - '\wmic.exe'
              - '\workfolders.exe'
              - '\wscript.exe'
    selection_child_susp_paths: # Idea: Laiali Kazalbach, Mohamed Elsayed (#4142)
        Image|contains:
            - '\AppData\'
            - '\Users\Public\'
            - '\ProgramData\'
            - '\Windows\Tasks\'
            - '\Windows\Temp\'
            - '\Windows\System32\Tasks\'
    condition: selection_parent and 1 of selection_child_*
False Positives
Unknown

False positive likelihood has not been assessed. Additional context may be needed during triage.