Sigma rule: Suspicious Outlook Child Process

Rule

Title

Suspicious Outlook Child Process

Status

test

Level

high

Author

Michael Haag, Florian Roth (Nextron Systems), Markus Neis, Elastic, FPT.EagleEye Team

Date

2022-02-28

Modified

2023-02-04

File

rules/windows/process_creation/proc_creation_win_office_outlook_susp_child_processes.yml

Commit

ccbb0369507f796db0b0ae6854c8a2be471b9d84

Detects a suspicious process spawning from an Outlook process.

Log source

product

windows

category

process_creation

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*

False positives (as the rule lists them)

• Unknown

Tags

• attack.execution
• attack.t1204.002

MITRE ATT&CK ids this rule names

• T1204.002

Related rules

• 438025f9-5856-4663-83f7-52f878a70a50 (derived)
• e212d415-0e93-435f-9e1a-f29005bb4723 (derived)

References

• https://www.hybrid-analysis.com/sample/465aabe132ccb949e75b8ab9c5bda36d80cf2fd503d52b8bad54e295f28bbc21?environmentId=100
• https://mgreen27.github.io/posts/2018/04/02/DownloadCradle.html

Read on 2026-11-03T00:58:21.399Z under licence sigma-drl-1.1@d5f4c36a from https://github.com/SigmaHQ/sigma/blob/ccbb0369507f796db0b0ae6854c8a2be471b9d84/rules/windows/process_creation/proc_creation_win_office_outlook_susp_child_processes.yml