Sigma rule: VMToolsd Suspicious Child Process

Rule

Title

VMToolsd Suspicious Child Process

Status

test

Level

high

Author

bohops, Bhabesh Raj

Date

2021-10-08

Modified

2023-07-25

File

rules/windows/process_creation/proc_creation_win_vmware_vmtoolsd_susp_child_process.yml

Commit

ccbb0369507f796db0b0ae6854c8a2be471b9d84

Detects suspicious child process creations of VMware Tools process which may indicate persistence setup

Log source

product

windows

category

process_creation

Detection

selection_parent:
    ParentImage|endswith: '\vmtoolsd.exe'
selection_img:
    - Image|endswith:
          - '\cmd.exe'
          - '\cscript.exe'
          - '\mshta.exe'
          - '\powershell.exe'
          - '\pwsh.exe'
          - '\regsvr32.exe'
          - '\rundll32.exe'
          - '\wscript.exe'
    - OriginalFileName:
          - 'Cmd.Exe'
          - 'cscript.exe'
          - 'MSHTA.EXE'
          - 'PowerShell.EXE'
          - 'pwsh.dll'
          - 'REGSVR32.EXE'
          - 'RUNDLL32.EXE'
          - 'wscript.exe'
filter_main_vmwaretools_script:
    Image|endswith: '\cmd.exe'
    CommandLine|contains:
        - '\VMware\VMware Tools\poweron-vm-default.bat'
        - '\VMware\VMware Tools\poweroff-vm-default.bat'
        - '\VMware\VMware Tools\resume-vm-default.bat'
        - '\VMware\VMware Tools\suspend-vm-default.bat'
filter_main_empty:
    Image|endswith: '\cmd.exe'
    CommandLine: ''
filter_main_null:
    Image|endswith: '\cmd.exe'
    CommandLine: null
condition: all of selection* and not 1 of filter_main_*

False positives (as the rule lists them)

• Legitimate use by VM administrator

Tags

• attack.execution
• attack.persistence
• attack.t1059

MITRE ATT&CK ids this rule names

• T1059

References

• https://bohops.com/2021/10/08/analyzing-and-detecting-a-vmtools-persistence-technique/
• https://user-images.githubusercontent.com/61026070/136518004-b68cce7d-f9b8-4e9a-9b7b-53b1568a9a94.png
• https://github.com/vmware/open-vm-tools/blob/master/open-vm-tools/tools.conf

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_vmware_vmtoolsd_susp_child_process.yml