Convert indexed Sigma rules into analyst-ready detections.

title: Suspicious Microsoft Office Child Process
id: 438025f9-5856-4663-83f7-52f878a70a50
related:
    - id: c27515df-97a9-4162-8a60-dc0eeb51b775 # Speicifc OneNote rule due to its recent usage in phishing attacks
      type: derived
    - id: e1693bc8-7168-4eab-8718-cdcaa68a1738
      type: derived
    - id: 23daeb52-e6eb-493c-8607-c4f0246cb7d8
      type: obsolete
    - id: 518643ba-7d9c-4fa5-9f37-baed36059f6a
      type: obsolete
    - id: 04f5363a-6bca-42ff-be70-0d28bf629ead
      type: obsolete
status: test
description: Detects a suspicious process spawning from one of the Microsoft Office suite products (Word, Excel, PowerPoint, Publisher, Visio, etc.)
references:
    - https://www.hybrid-analysis.com/sample/465aabe132ccb949e75b8ab9c5bda36d80cf2fd503d52b8bad54e295f28bbc21?environmentId=100
    - https://mgreen27.github.io/posts/2018/04/02/DownloadCradle.html
    - https://thedfirreport.com/2021/03/29/sodinokibi-aka-revil-ransomware/
    - https://doublepulsar.com/follina-a-microsoft-office-code-execution-vulnerability-1a47fce5629e
    - https://github.com/vadim-hunter/Detection-Ideas-Rules/blob/02bcbfc2bfb8b4da601bb30de0344ae453aa1afe/Threat%20Intelligence/The%20DFIR%20Report/20210329_Sodinokibi_(aka_REvil)_Ransomware.yaml
    - https://github.com/splunk/security_content/blob/300af51b88ad5d5b27ce4f5f54e4d6e6a3a2c06d/detections/endpoint/office_spawning_control.yml
    - https://twitter.com/andythevariable/status/1576953781581144064?s=20&t=QiJILvK4ZiBdR8RJe24u-A
    - https://www.elastic.co/security-labs/exploring-the-ref2731-intrusion-set
    - https://github.com/elastic/detection-rules/blob/c76a39796972ecde44cb1da6df47f1b6562c9770/rules/windows/defense_evasion_execution_msbuild_started_by_office_app.toml
    - https://www.vmray.com/analyses/2d2fa29185ad/report/overview.html
    - https://app.any.run/tasks/c903e9c8-0350-440c-8688-3881b556b8e0/
author: Florian Roth (Nextron Systems), Markus Neis, FPT.EagleEye Team, Vadim Khrykov, Cyb3rEng, Michael Haag, Christopher Peacock @securepeacock, @scythe_io
date: 2018-04-06
modified: 2023-04-24
tags:
    - attack.defense-evasion
    - attack.execution
    - attack.t1047
    - attack.t1204.002
    - attack.t1218.010
logsource:
    category: process_creation
    product: windows
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_*
falsepositives:
    - Unknown
level: high