Convert indexed Sigma rules into analyst-ready detections.

title: Suspicious Outlook Child Process
id: 208748f7-881d-47ac-a29c-07ea84bf691d
related:
    - id: 438025f9-5856-4663-83f7-52f878a70a50 # Office Child Processes
      type: derived
    - id: e212d415-0e93-435f-9e1a-f29005bb4723 # Outlook Remote Child Process
      type: derived
status: test
description: Detects a suspicious process spawning from an Outlook process.
references:
    - https://www.hybrid-analysis.com/sample/465aabe132ccb949e75b8ab9c5bda36d80cf2fd503d52b8bad54e295f28bbc21?environmentId=100
    - https://mgreen27.github.io/posts/2018/04/02/DownloadCradle.html
author: Michael Haag, Florian Roth (Nextron Systems), Markus Neis, Elastic, FPT.EagleEye Team
date: 2022-02-28
modified: 2023-02-04
tags:
    - attack.execution
    - attack.t1204.002
logsource:
    category: process_creation
    product: windows
detection:
    selection:
        ParentImage|endswith: '\OUTLOOK.EXE'
        Image|endswith:
            - '\AppVLP.exe'
            - '\bash.exe'
            - '\cmd.exe'
            - '\cscript.exe'
            - '\forfiles.exe'
            - '\hh.exe'
            - '\mftrace.exe'
            - '\msbuild.exe'        # https://github.com/elastic/detection-rules/blob/c76a39796972ecde44cb1da6df47f1b6562c9770/rules/windows/defense_evasion_execution_msbuild_started_by_office_app.toml
            - '\msdt.exe'           # CVE-2022-30190
            - '\mshta.exe'
            - '\msiexec.exe'
            - '\powershell.exe'
            - '\pwsh.exe'
            - '\regsvr32.exe'
            - '\schtasks.exe'
            - '\scrcons.exe'
            - '\scriptrunner.exe'
            - '\sh.exe'
            - '\svchost.exe'        # https://www.vmray.com/analyses/2d2fa29185ad/report/overview.html
            - '\wmic.exe'           # https://app.any.run/tasks/c903e9c8-0350-440c-8688-3881b556b8e0/
            - '\wscript.exe'
            # Several FPs with rundll32.exe
            # We started excluding specific use cases and ended up commenting out the rundll32.exe sub processes completely
            # - '\rundll32.exe'
            # filter_outlook_photoviewer:  # https://twitter.com/Luke_Hamp/status/1495919717760237568
            #   ParentImage|endswith: '\OUTLOOK.EXE'
            #   Image|endswith: '\rundll32.exe'
            #   CommandLine|contains: '\PhotoViewer.dll'
            # filter_outlook_printattachments:  # https://twitter.com/KickaKamil/status/1496238278659485696
            #   ParentImage|endswith: '\OUTLOOK.EXE'
            #   Image|endswith: '\rundll32.exe'
            #   CommandLine|contains|all:
            #     - 'shell32.dll,Control_RunDLL'
            #     - '\SYSTEM32\SPOOL\DRIVERS\'
    condition: selection # and not 1 of filter*
falsepositives:
    - Unknown
level: high